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I Workshop on Heritage Stones

Salamanca (Spain) 2-4 October 2018

2018 is a year of celebrations. Salamanca celebrates the 800 anniversary of its

university, the oldest of Spain and one of the oldest in the world. Salamanca also

celebrates the 30th anniversary of its designation as World Heritage site by UNESCO, in

1988. But 2018 is also the European Year of Cultural Heritage. For all these reasons, it

was the perfect date to organize the I Workshop on Heritage Stones. This workshop is

organized in the frame of the University anniversary and of the UNESCO-IGCP-637.

Participants will discuss on the initiatives of the IUGS Heritage Stones Subcommission,

such as the Global Heritage Stone Resource designation, and other matters related to

stones and heritage. During the workshop, there is a session for contributions. Abstracts

for these contributions are assembled in the following pages.

We hope this workshop will be the first of a series of successful meetings.

Compiled by: Lola Pereira

Reviewers:

• Lidia Catarino

• Giovanna Dino

• Víctor Cárdenes

• Björn Schouenborg

• Antonio Gilberto Costa

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Content.-

Introduction.

7 R. Oberhänsli, K. Klappenbach, U. Altenberger, M. Ziemann, J. Mullis, S. Laue:. Mineralogy – Detective work for

restoration.

11 E. Errami: Heritage Stones between use and patrimonialization: examples from Morocco.

13 Z.C.G. Silva, T. Heldal: Granites and “Granites” in the stone industry nomenclature - A review.

17 P. Primavori and J. Cassar: Carbonate stones used in heritage buildings and today: compositional,

commercial and conservation aspects of marble and limestone.

19 V. Cárdenes Van den Eynde: Slates for roofing and more.

21 M.H. Barros de Oliveira Frascá: Granitic rocks deterioration and related mechanism.

23 S. Garg, P. Kaur, Aman, M. Pandit, Fareeduddin, G. Kaur, A. Kamboj: Makrana marble from North-

Western India: an ideal Global Heritage Stone Resource.

27 G. Kaur, M. F. Makki, R.K. Avasia, B. Bhusari, R. Duraiswami, M.K. Pandit, Fareeduddin, R. Baskar, S.

Kad: The late Cretaceous/Paleogene Deccan traps: a Global Heritage Stone Province from India.

31 F. Fratini, E. Pecchioni, E. Cantisani: Pietraforte Sandstone: the building material of middle age in

Florence.

35 E.A. Del Lama, M.H. Barros Oliveira Frascá. Itaquera granite in São Paulo city, Brazil.

39 L. Sousa, J.M. Lourenço, D. Pereira: Quarrying: vital activity in the past, banned activity in the future?

43 V.K. Sharma and B.J. Cooper:. Indian Charnockite: a potential Global Heritage Stone.

45 M. Brocx, K. Page, V. Semeniuk: Geohistorical information to be derived from building stones – the

Portland Limestone case study.

49 M. Brocx, V. Semeniuk: Building stones - a protocol to raise public consciousness.

51 A.G. Costa: Steatites of Brazil as contenders for the Global Heritage Stone Resource.

53 N. Careddu and S.M. Grillo: “Trachytes” from Sardinia: Geoheritage and innovation.

57 F. Gambino, A. Borghi, G.A. Dino, P.G. Rossetti, D. Castelli: Balma Syenite (Cervo Valley – Bi,

Northern Italy): A nearly unique material which could be designated as heritage stone.

61 L. Dias, T. Rosado, A. Candeias, J. Mirã, A.T. Caldeira. A closer look into limestone sculptures

degradation from Portuguese national museum of ancient art.

65 F. Torre, G.A. Dino, A. Torre, M. Dino: A walk in a stone village in Madonie mountains (Sicily, Italy):

Petralia Sottana (PA) urban geotour.

69 G. Kaur, P. Kaur, S. Garg, S. Singh, M. Pandit, P. Agrawal, A. Ahuja: Vindhyan Sandstone: the

crowning glory of architectonic heritage from India.

73 L. Lopes, J. Mirão, L. Dias: Limestones and marbles from Portugal: colors, textures and patterns.

77 J. E. Becerra Becerra, D. Benavente, J.C. Cañaveras: The sandstone “Piedra Bogotana” as Heritage Stone in Colombia.

79 D. M. Freire-Lista and A.Zalooli: Historic setts used as pavements of Madrid (Spain).

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MINERALOGY – DETECTIVE WORK FOR RESTORATION

R. Oberhänslia*, K. Klappenbachb, U. Altenbergera, M. Ziemanna, J. Mullisc, S. Laued

aInstitute for Earth- & Environmental Sciences, University Potsdam: Karl Liebknechtstr.24, Potsdam, Germany, 14467; bPrussian Palaces and Gardens Foundation Berlin-Brandenburg:

Post Box 60 14 62, Potsdam, Germany, 14414; cMineralogisch-Petrographisches Institut, Universität Basel: Bernoullistrasse 30, Basel, Switzerland, CH-4056; aUniversity of Applied

Sciences, Section Conservation & Restoration, Kiepenheuerallee 5, Potsdam, Germany, 14469; *[email protected]

Introduction Most of the questions in our cooperation with the Prussian Palaces and Gardens Foundation Berlin-Brandenburg, and many State Conservation Authorities with respect to the restoration of historic buildings, stones and minerogenic objects concentrate on: - Identification of the material; - Origin of material; - Search of material for replacement.

Identification and Origin For material identification laboratory investigations are often impossible, not wanted by the conservation responsible or sampling with minimal impact is difficult or impossible. To fulfil the tasks needed, modern mineralogy offers a set of mobile tools and methods that are not invasive. Besides using the classical tools such as eye, hand lens and brain we dispose of a mobile LIBS and developed a mobile Raman spectrometer that unlike the commercial mobile apparatus is up to the standards of a laboratory instrument. Further we make use of a handheld X-ray spectrometer and the classical analytical methods used in mineralogy and petrology such as electron microprobe (EMPA), scanning electron microscope (SEM), cathodoluminescence (CL), atomic emission spectroscopy (ICP-AES), laser ablation mass-spectroscopy (LA-ICP-MS) and Ar/Ar isotopes. Laser induced breakdown spectroscopy (LIBS) can analyse any matter regardless of its physical state (gas, liquid, solid) and detect almost all elements of the periodic system very quickly almost without destruction. If well calibrated, chemical analyses for micro-spots in minor amounts (> 1 microgram) are accurate to ca. 10-5 % in the range of > 10 to < 100 ppm. Despite the laser generated plasma the material is not significantly heated. Our mobile spectrometer is heavy and its “mobility range” is restricted to the length of the analytical arm. Raman spectroscopy allows for analyses of almost all molecular matter, be it organic or inorganic chemical compounds, pigments, glass or minerals. The analyses are completely contactless and non-destructive. Our mobile Raman spectrometer has been designed and constructed by Martin Ziemann with the help of the producer. The motivation was that commercial hand held Raman spectrometer did not provide the accuracy needed for precise analyses. Secondly their mobility is generally limited with respect to access to analytical spots with respect to distance and height above ground (Fig.1). Laser excitation is from an Nd: YAG laser DSPD 532. A micro-objective allows for high resolution with a diameter of 1-3 µm for the laser focus. The measuring point on the wall is selected with a second, internal camera, which

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provides a microscopic image of the object surface and the laser spot. With our instrument we achieve resolution and accuracy comparable to a high-class laboratory instrument.

Figure 1. Mobile Raman measuring pigments on a fresco of Late Middle Age in the Franciscan church of Angermünde; 4.5 m above ground. (photo Ziemann) Research in collaboration with the “Prussian Palaces and Gardens Foundation, Berlin-Brandenburg” focussed on the Grotto Hall of the New Palais in Potsdam and lustres. For the Grotto Hall the major aim was a documentation of the minerals used for decoration and a damage assessment as base for restoration. During times parts of the original grotto decoration with slags, gypsum and minute glass shards was replaced with alternating mineral stripes mostly of quartz crystals but also with fossils, rocks, minerals, ore minerals and gems. Based on simple mineralogical observation combined with Raman investigations of minerals and their inclusions it was possible to identify mineral assemblages with certain regional characteristics that in combination with archives files allowed identifying the “collector”. In general all regents got stones and mineral as presents, depicting their political and commercial networks. And, collecting minerals was a fundamental part of the education of princes and princesses. A fine mineralogical detail was the detection of yellow potassium-hexacyanoferrate(II) [prussiate] crystals and a coating of Prussian Blue [iron(III)-hexacyanoferrate(II)] on the neighboring minerals. Lustres are prone to destruction as all delicate objects over times, especially with harsh events such as wars. We investigated fragments of lustre quartz to identify the provenance of quartz of Frederician (II) lustres. Archive studies did not provide more than the producers and the prices. Based on literature search evidence for a provenance from the Alps rather than far continents

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was found. Investigation of fluid inclusions from the remnants and comparison with fluid inclusion studies from the Alps allowed to identify the provenance of the quartz and finally to find not only the localities in the Alps but through further archive work the path of delivery to the producers. Keywords: LIBS, Raman, FLINC, quartz, provenance.

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HERITAGE STONES BETWEEN USE AND PATRIMONIALISATION: EXAMPLES FROM MOROCCO

E. Errami

Equipe de Géodynamique, Géo-éducation and Patrimoine Géologique (EGGPG), Chouaïb

Doukkali University, Faculty of Sciences, B.P. 20, 24000, El Jadida, Morocco. Email: [email protected]

This keynote aims to highlight the diversity of the building and ornamental stones offered by the Moroccan geology, to promote them as geological and geo-archeological heritage stones and to highlight the necessity to link the historical sites to the sites where they were quarried to allow human and socio-economic development of remote areas and help promoting a new touristic niche, geotourism. Morocco, named paradise of geologists, consists of a very long and rich geological heritage that begins ca 2000 million years ago from Archean to Quaternary. It is also characterized by its immense geological outcrops due to its climate. This geoheritage consists of various magmatic, metamorphic and fossils rich sedimentary rocks and of geosites corresponding to stratotypes, faults, folds, sedimentary structures…, reflecting various tectonic, magmatic and paleo-environments events that have occurred during the geological history of the region. This rich and diverse geology offers various building and ornamental rocks that gives to the Moroccan historical and traditional buildings a local spirit and make them fit very well with their local environment. Numerous natural stones present different physical properties and esthetical characteristics that allow their use in different purposes, as building or ornamental rocks on the exterior and interior of monuments and buildings, floors, fountains, pools and other design projects. Some of them contribute significantly to the architectural heritage of specific Moroccan cultural heritage since the Roman time and the first traces of the stones exploitation were located in the vicinity of Roman cities (Volubilis, Lixus, Chellah). During the Islamic period (7th - 8th century), rocks were less used and earthen architecture was preferred to build mosques, Kasbahs and granaries, historic city centers and archaeological sites. The cultural importance of this architecture throughout the world allows its consideration as a common world heritage that deserves protection and conservation. Ancient massive extraction of metamorphosed calcarenites and limestones dates back to the period of Almohads dinasty (12th - 13th centuries) and was used in the construction of their main historical monuments, such as Hassan Tower and Oudayas Kasbah in Rabat or the Koutoubia Mosque in Marrakech. Although the first industrial exploitation of building and ornamental stone in Morocco were created in the beginning of the 20th century with the installation to the European marble work companies that contribute to a rapid expansion of marble production from central Morocco region. Then the exploitation declines with the Morocconization of the companies after the independence of the country. However, end to the 20th century, the construction of the Hassan II Mosque in Casablanca, has ensured a new expansion of production, using exclusively local ornamental rocks from different regions of Morocco. In most historical building, the used building and ornamental stones are no longer extracted. Formal recognition of these stones might help to ensure the protection of old quarries

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as geo-archeological sites and also for possible future use in restoration. Linking the cultural monuments to the quarries where rocks were extracted will help to protect, maintain and valorize old quarries for education and geotourism, which could help developing remote areas at the same level as areas where the historical sites are situated. To increase the awareness of local communities and policy makers about the importance of their geo-archeological heritage and the necessity to protect and to valorize it for a local human and socio-economic development, an adequate capacity building and educational activities are needed. This is an efficient way to increase ownership and create strong community organization focused of the geo-archeological heritage. A well-documented GIS data base on building and ornamental heritage stones is needed to allow governments and policy makers to build strategies for their sustainable socio-economic use. To conclude, the creation of geoparks in different region of Morocco that include extracted or non-extracted building and ornamental rocks will help increasing awareness on the geological and geo-archeological heritage. Creating outdoor and indoor museums in geoparks is necessary to display this valuable heritage including building and ornamental stones and to protect and valorize old quarries through well documented trails (Interpretative panels, flyers, leaflets, brochures…). Therefore, to enhance and preserve this national and international heritage that have scientific, educational and socio-economic values, it is necessary to elaborate a clear regulation to ovoid the disappearing of rare or unique stones that deserve to be classified as national or world cultural heritage. Keywords: building and ornamental Stone heritage, Morocco

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GRANITES AND “GRANITES” IN THE STONE INDUSTRY NOMENCLATURE -

A REVIEW

Z.C.G. Silvaa*, T. Heldalb

aGeoBioTech, Geology Department, Faculdade de Ciências e Tecnologia, University Nova de

Lisboa. 2829-516 Caparica, Portugal; bGeological Survey of Norway, Postboks 6315 Torgarden, 7491 Trondheim, Norway *Corresponding author Email Address: [email protected]

Introduction The term “GRANITE” is commonly applied by the dimension stone industry for most kinds of hard silicate rocks, including a range of igneous and metamorphic rock types. Even quartzite, which is a much common term even within the stone industry, is often wrongly presented as “granite” (i.e., Macaubas Blue “granite” from Brazil). Although such rocks may have certain physical properties in common, such as high compression and bending strength and low open porosity, there are also rather extreme variations in other properties that finally decide durability and appropriate areas of use. One may have sympathy with the need for a simplification of a rather complicated geological nomenclature, but it is questionable if the present practice actually serves to the benefit for the dimension stone industry and its customers. Below, such aspects will be illustrated through examples. “Granites” and other igneous rocks According to the IUGS classification, a “true granite” is a plutonic rock composed of quartz (20-60%), Potassium feldspar (35-90%), plagioclase feldspar (10-65%) and a smaller amount of other minerals. Within this range of composition, the rocks share most physical and chemical properties and even color, mostly ranging from grey to pink and reddish. Thus, “true granites” are comparable regarding performance in use. However, other igneous rocks, as shown in Figure 1, may deviate significantly. For example, the “Blue Bahia” syenite from Brazil (promoted as “granite”) contains the blue mineral sodalite, which will fade when exposed to a humid and polluted atmosphere containing chlorine. Under such circumstances, the mineral structure is disturbed by the chlorine ion and collapses. In other words, the rock will perform significantly different to “true granite” under certain conditions. Similar problems (related to mineral solubility and alteration) may arise for other igneous rocks containing sodalite or other feldspathoid minerals, such as nepheline, i.e. plotting under the central line in the diagram of Figure 1. The industrial term “black granite” is applied on rocks as different as gabbro/norite (“Zimbabwe Black”) and anorthosite (“Angola Black”), the first containing mafic minerals (pyroxene and/or amphibole) as a major constituent, the latter more than 90% plagioclase feldspar. The differences in mineral composition are surely reflected in quality aspects. Whilst such differences are hidden under the term “black granite”, similarities in quality between “black” and more light-colored anorthosites are also hidden, since they fall into different groups due to their color alone (i.e., “Angola Black” versus the Norwegian “Blue Antique”).

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Charnockite is a group of granitic to monzonitic rocks containing orthopyroxene. They were formed under high-pressure conditions at deep levels in the crust, and there are continuous discussions about their origin being “truly” magmatic or “truly” metamorphic. Many well-known dimension stone types are charnockites, such as the Brazilian “Ubatuba” and the Norwegian “Arctic Black”, both displaying a dark greenish color, owed to intergrowths and thin veinlets throughout the rock, mostly in feldspar and quartz (Fig 2). Warm hydrochloric solution is able to wipe its green color as the iron is leached out. In a similar process, the rock green color turns to yellow when the rock is exposed to the sun. Thus, the huge group of “industrial granite” include rocks with rather large differences in performance. It creates a false image of similarities between rocks containing almost 100% quartz and those with none, between rocks rich in soluble minerals and those containing only un-soluble ones.

Research on rock properties The knowledge of performance of different rocks under various conditions is a key aspect of quality assessment and to the predictability and finally the choice of material for a specific project. After two decades of research among the authors, studying rock alteration exposed to aggressive environment, it seems clear that within the so-called “industrial granite” there are significant differences in performance, due to:

• Compositional differences (mineralogy) • Textural and structural differences • Geochemical differences • Genetic aspects (formation and later geological history)

Figure 1. Simple classification scheme for plutonic, igneous rocks (Streckeisen diagram) based on four main mineral components. Including some dimension-stone types commonly promoted as “granite”.

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Such differences may create viable and usable results when applied to a proper geological classification of rocks, although make little sense within the industrial terminology. Conclusions The correct definition of rock used in the industry and the knowledge of their limitations when applied in different environments should be taken into account whenever choosing rock for constructions in order to preserve the original purpose of the rock use and to avoid its deterioration. Moreover, this may increase the awareness around the use of traditional stone materials, their specific quality and performance through history. Too much simplification has its price, and in the authors opinion both the stone-producing industry and the customers will lose. It is necessary to have a better communication and diffusion of information among researchers, producers and end-users regarding the alteration of those rocks and their proper use in construction to avoid damage on the material.

Figure 2. Photomicrograph of a charnockite showing the thin veinlets through the feldspar grain (|| Nicols, x 20). Keywords: granite, “granite”, mineral composition, igneous rocks

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CARBONATE STONES USED IN HERITAGE BUILDINGS AND TODAY: COMPOSITIONAL, COMMERCIAL AND CONSERVATION ASPECTS OF MARBLE

AND LIMESTONE

P. Primavoria, J. Cassarb*

a PSC Primavori Stone Consulting, Milan, Italy b Department of Conservation and Built Heritage, University of Malta, Malta *[email protected]

Introduction A carbonate rock, by definition, consists of more than 50% of carbonate minerals, calcite and/or dolomite. Within this category fall the limestones, marble and dolostones which have for thousands of years been used for construction and decorative purposes. This is because of their availability, ease of working, beauty, ability to take a polish, and/or durability. When mentioning these materials, the prehistoric (limestone) Temples of Malta, the (marble) Acropolis of Athens, the wide-ranging exploitation, exportation and use of coloured marbles by the Romans, the David (marble) by Michaleangelo, and countless other prestigious monuments, sites and statuary come to mind. Today, these materials remain important contributors to the economy, not least of all through tourism, and the construction industry. Description of the Work or Project This presentation will start with a general introduction on the general composition, properties and use of these materials, specifically porous limestones and marble, not only over time but also today, with examples particularly from Europe. It will also delve into the common use of the term “marble” to include also polishable limestones. The second part of the presentation will deal with marble in the dimension stone sector today, and will include aspects of nomenclature and classification (scientific and commercial classification), as well as genesis, chemistry and mineralogy – this will include a discussion of colour and veining, texture, grain size and anisotropy, technical properties, surface treatments and weathering. Examples of the most representative marbles in Europe will also be given. In the third part of the presentation, the subject of limestones will be tackled, distinguishing first polishable limestones from marbles. The focus will then fall on soft porous limestones, widely used in the Mediterranean, and beyond, over time – this will include composition, properties and types, their historical use and problems of their deterioration and conservation. Examples will be given. Conclusions The presentation will end with a summary of the importance of these materials: in the past, in the present, and forecasting their use and importance in the future. Keywords: porous limestones; marble; composition and properties; classification; weathering.

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SLATES FOR ROOFING AND MORE

V. Cárdenes Van den Eynde a*

a Department of Geology, Oviedo University, 33005 Oviedo, Spain

*[email protected] Introduction A slate is a metamorphic rock displaying slaty cleavage, a planar structure that naturally allows the splitting of this rock. Slates have been used for many different purposes in history, not just the typical constructive uses (roofing, paving, walling, etc.), but also to erect tombstones, to manufacture switchboards, and especially, as artistic support, among many other things. This work gives an overview of the most representative uses given to slates. Description of the Work Many objects can be done with slate, a fine-grained and homogeneous rock that can easily split in large planes due to its unique structure, the slaty cleavage. This characteristic makes slate a very versatile rock from a construction point of view. The application for which slate is better known is perhaps construction, but slate has had great importance in art. An example of the first uses of slate as religious art are the plate idols from Extemadura, Spain, the animal engravings from Hunsrück, Germany, or the slate mirrors created by the Maya in Pacbitun, Belize. In more recent times, it is noticeable the paints using slate as pictorial support made by Titian, one of the most remarkable painters from the Venetian school, or the reliefs in the slate columns found in buildings from Genova, Italy. Slate has also been profusely to make tombstones in Pennsylvania (USA), Wales, or Walyunga (Australia). However, there is none literature regarding conservation procedures for slate heritage objects. This creates confusion among curators and restorers, which in many cases don´t know how to perform restoration procedures on slates. Conclusions The present work is a review of the main uses of slate, both in construction and arts. The abundance and singularity of slate heritage objects makes necessary the development of specific literature and a protocol to address conservation and restoration actions on these objects. Keywords: slate; construction technology;

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GRANITIC ROCKS DETERIORATION AND RELATED MECHANISM

M.H. Barros de Oliveira Frascá*

MHB Geological Services, São Paulo, SP – Brazil *Corresponding author [email protected]

Introduction Stone is the main construction material found in historical monuments and buildings, because of their availability, resistance and durability. Granitic rocks were and are largely used due to their greater durability as well as textural, structural and colour varieties. Granitic Rocks Deterioration and Related Mechanism Stone material in the built heritage undergoes alteration and/or deterioration in response to the long-time exposure to weather conditions and its variations as well as to aggressive or polluted environment (urban and industrial) and poor conservation procedures. Regarding granitic rocks, among the weathering agents, the crystallization of salts is the most powerful and is the leading cause of rock alteration either in marine environments, humid climates or polluted environments. The main degradation mechanism is the pressure resulting from the crystallization of soluble salts in porous media, resulting in loss of grain cohesion that may be observed by a great variety of deterioration forms, such scaling, exfoliation, granular disaggregation (Fig. 1) and others.

Figure 1 – Granular disaggregation of granite gneiss in the kitchen of São Bento Monastery, Rio de Janeiro, Brazil. Photo: Maria Heloisa B. O. Frascá

The microcracks and other microdiscontinuities usually present in granitic rocks play the main task in the salt crystallization deterioration process, as they are the pathway for migration of the saline or acidic solution – that may also result in salts after microorganism action (a biodeterioration process) – and the place where salt crystallize (as subefflorescence) under appropriate conditions of saturation and evaporation. The process is marked by swelling, scaling and breaks. Conclusions Subefflorescences resulting from the concentration and crystallization of salts, diluted in water and carried through microcracks are the main responsible for granitic rocks deterioration. Keywords: granitic rocks, salt crystallisation, stone deterioration, microdiscontinuities.

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,

MAKRANA MARBLE FROM NORTH-WESTERN INDIA: AN IDEAL GLOBAL

HERITAGE STONE RESOURCE

S. Garg1, P. Kaur1#, Aman1, M. Pandit2, Fareeduddin3, G. Kaur1* A. Kamboj

1Department of Geology, Panjab University, Chandigarh 160014, India 2Department of Geology, Rajasthan University, Jaipur, India

3Geological Survey of India, Bangalore, India *Corresponding author: [email protected]

Introduction The iconic Taj Mahal, one of the Seven Wonders of the World (https://world.new7wonders.com/), is a monumental tomb built entirely in Makrana white marble. Taj Mahal was declared a UNESCO world heritage site in 1983 and symbolizes India. The Monument has stood the test of the time and has retained its aesthetics, grace, splendour and charm for almost four centuries now. This can be attributed entirely to the pure white crystalline variety commonly known as ‘Sangemarmar’ viz. white/ivory stone, quarried from a single deposit at Makrana town in Rajasthan state of north-western India.

Marble has been one of the most preferred ornamental masonry stone since antiquity and used in several heritage buildings and monuments all over the world. The Makrana marble is, however, unique, for its textural and mineralogical attributes that have made it resistant to tarnishing. The marble is exposed to the west of Makrana town as five prominent NNE – SSW trending, 13 km long bands where it occurs intercalated with calc-silicate rock and calcareous quartzite. These five bands of Makrana marble viz. i. Devi Gunavati band; ii. Dungri band; iii. Pink band; iv. Makrana Kumhari band; v. Borawar Kumhari band-I & II, represent different varieties of marbles in terms of composition, colour and texture. The differences in these bands are attributed to local facies variation during their formation. The purest marble with white colour can be attributed to pure calcitic composition (>99% CaCO3) while shades of gray and pink can be attributed to minor silicate mineral impurities (up to 1%). Its highly crystalline and compact texture renders it low porosity and makes it corrosion resistant. Its unique texture makes it hard, strong, durable and tarnish resistant over a long period and thus an ideal material for monuments and buildings.

The Victoria Memorial in Kolkata is one of the most adorable monuments in eastern India that is made entirely of Makrana marble. Besides, Makrana marble has also been a major building stone for several forts, palaces and archeologically significant buildings in north-western India viz. Red Fort, Humayun’s tomb, Akbar’s tomb, to name a few. The international use of Makrana marble includes the Sheikh Zayed Mosque, Abu Dhabi, UAE and Moti Masjid, Lahore, Pakistan.

Mining at Makrana started almost 400 years back and is one of the longest open cast mining

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activity. Presently, around 400 quarries are operational using both semi-mechanized and manual mining methods. Makrana marble is extensively used as a dimension stone for construction of temples, mosques, shopping complexes, buildings and flooring etc. It is aesthetically used in the handicrafts, sculpture work, fine carvings. The Makrana marble is quite popular in the international markets and is exported to several Persian Gulf countries, the European countries, USA, Canada, etc.

The Makrana marble is already an established iconic stone that has been used in one of the most adorned monuments of the world. In combination with its unique geological properties, it fulfils all the criteria and norms to be named as a Global Heritage Stone Resource.

Figure 1. Two different quarry sites in Makrana, Rajasthan, India. (a) Side view of quarry site (Photo: Parminder Kaur); (b) Top view of quarry site (Photo: Gurmeet Kaur).

Figure 2. Hand specimens collected from quarry sites in Makrana, Rajasthan, India. (a) Pure variety Makrana White (Sangemarmar); (b) Pink variety of Makrana marble. Photos: Sanchit Garg.

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Figure 3. World famous monuments built from Makrana marbles: (a) Taj Mahal, Agra, Uttar Pradesh, India. (https://economictimes.indiatimes.com/magazines/panache/taj-mahal-named-second-best-unesco-world-heritage-site-after-angkor-wat/articleshow/61948119.cms);(b) Birla Temple, Jaipur, Rajasthan, India (Photo: Parminder Kaur); (c) Victoria Memorial, Kolkata, West Bengal, India (https://www.hindustantimes.com/india-news/cisf-takes-over-victoria-memorial-security-in-kolkata/story-7KwVNmEmY79byyCmu0U2PJ.html);(d) Sheikh Zayed Mosque, Abu Dhabi, UAE. (https://fineartamerica.com/featured/2-sheikh-zayed-mosque--abu-dhabi--uae-luciano- mortula.html).

Keywords: Taj Mahal, Makrana marble, Export, Quarries, Heritage

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THE LATE CRETACEOUS/PALEOGENE DECCAN TRAPS: A GLOBAL HERITAGE

STONE PROVINCE FROM INDIA

G. Kaura#, M. F. Makkib, R.K. Avasiac, B. Bhusarid, R. Duraiswamie*, M.K. Panditf, Fareedudding, R. Baskarh, S. Kada

aCAS in Geology, Panjab University, Chandigarh, India; bB-36, Abhimanshri Society, Pashan Road, Pune, India; cDepartment of Geology, Saint Xavier’s College, Mumbai, India; dGeological Survey of India, Pune, India; eDepartment of Geology, Savitribai Phule Pune University, Pune, India; fDepartment of Geology, Rajasthan University, India; gGeological Society of India, Bangalore, India; hDepartment of Environmental Science and Engineering, Guru Jambeshwar University of Science and Technology, Hisar, Haryana, India

*Corresponding author:[email protected]; # Presenting author: [email protected]

The Late Cretaceous/Palaeogene Deccan Traps are spread over half a million square kilometres in west-central parts of the Indian Peninsula and form one of the most spectacular and prominent geologic and geomorphologic features in the Indian subcontinent. The vast expanse of Deccan Traps comprises predominantly basalts and subordinate felsic and alkaline rocks (trachytes, rhyolites, and tinguaites). These rocks have been extensively used by the inhabitants of this region since antiquity and have cultural, religious and historical significance. In this presentation we showcase geological, geomorphological and petrological attributes of the two variants of Deccan Traps, namely basalt and trachyte, underlining their cultural and architectonic attributes to propose their assignment as Heritage Stone Resource. The Deccan Trap rocks were chosen by the civilisations in the western and central India for construction, sculpturing and rock carvings. The famous Buddhist and Hindu cave temples viz. Ajanta, Ellora and Elephanta were carved in-situ in the basalts during ancient Indian civilizations and are now recognized as UNESCO world heritage sites. The easy breakability of these rocks into blocks of desired sizes, shapes and dimensions made them suitable for the construction of temples, forts and other historical buildings built during the last few centuries. The most sought after variety for construction purpose was the dark, fine grained, hard and compact basalt. The palace of the Ruler Peshwa, Savitribai Phule Pune University’s administrative block (residence of the Governor of the erstwhile Bombay State), Deccan college are some of the well known architectonic heritage made of basalt in the state of Maharashtra. The basalt quarries nowaday’s produce materials for building purposes, road metal, corrosion resistant basaltic pipes that are in great demand internationally. The non-vesicular basalt is also suitable for unlined tunnels economising the engineering projects in the Deccan Trap region. Basalt quarries from northern and western Maharashtra are known to produce the finest, exotic zeolites from this part of Deccan province. The occurrence of rare green apophyllite, blue cavansite, and black babingtonite are unique to the Deccan Trap province. These spectacular minerals found in the Deccan Traps are exported and exhibited worldwide.

The associated felsic variant, namely trachyte was the preferred building stone in a number of iconic and heritage buildings built by Britishers during the early twentieth century in Bombay (now Mumbai) viz: The Gateway of India, Chhatrapati Shivaji 27



Railway Terminus (erstwhile Victoria Terminus), Mumbai Municipal Corporation, to name a few. Most of these buildings have been built in Indo Saracenic Style depicting colonial and Victorian eras and are symbolic of architectonic heritage of the western India. The trachyte used in building the above heritage was quarried locally from north Bombay. Trachyte is now no more used for building owing to rampant urbanization of the city leading to disappearance of most quarries of trachytes in the last few decades. The relict trachyte exposures can be noticed in some parts of Mumbai. The Deccan Trap rocks, namely basalt and trachyte, bear testimony to India’s cultural and architectonic heritage and fulfil the requisite for heritage criteria specified by the Heritage Stone Subcommission (HSS) and thus are strong candidates to be recognized as a Global Heritage Stone Resource (GHSR). It is worthwhile to mention that both basalt and trachyte of the Deccan traps are in geographic and geological proximity with each other and this qualifies Deccan trap province to be recognised as Global Heritage Stone Province (GHSP) from this subcontinent in consonance with the criteria for GHSP mentioned in the terms of reference given by HSS.

Figure 1. Quarry sites in Deccan Traps. Left side: Columnar basalt quarry from Andheri, Mumbai (Photo: S. Viladkar); Right side: Abandoned basalt quarry site in Wagholi, Pune (Photo: Satwinder Arora).

Figure 2. Cave temples of Ajanta and Ellora (UNESCO world heritage sites). These cave temples were carved in-situ in massive variety of Deccan basalts, Maharashtra, India. (Photos: Anuvinder Ahuja)

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Figure 3. Two famous educational institutions constructed from locally quarried basalt. Left side: Ferguson college, Pune (Source: https://collegedunia.com/college/1284-fergusson-college-pune/gallery); Right side: Saint Xaviers college, Mumbai (Photo: Satwinder Arora).

Figure 4. Left side: The famous Bombay Municipal Corporation building (BMC); Right side: Close up view of the trachyte (commonly known as golden basalt) used in the construction of BMC and most of the buildings in Mumbai during the early twentieth century. (Photos: Satwinder Arora)

Figure 5. Left side: The Gateway of India, Mumbai; Right side: Close up of the top front view of the Gateway of India built in trachyte. (Photos: Satwinder Arora) Acknowledgements: Authors Fareeduddin and Gurmeet Kaur gratefully acknowledge UNESCO-IUGS IGCP-637 for granting partial funds to attend the Workshop

Keywords: Basalt, Trachyte, Deccan Trap, West-central India, Resource, Province 29



PIETRAFORTE SANDSTONE: THE BUILDING MATERIAL OF MIDDLE AGE IN

FLORENCE

F. Fratinia, E. Pecchionia,b*, E. Cantisania

a CNR- Institute for Conservation and Valorization of Cultural Heritage Via Madonna del Piano, 10 Sesto Fiorentino (Florence-Italy) 50019; bEarth Science Department University of Florence

Via G. La Pira, 4 Florence Italy 50121 *Corresponding author [email protected]

Introduction Pietraforte was the main construction material during Middle Age in Florence, Italy (civic residences, public and private palaces, religious buildings, street pavement) and it has given the city its typical warm chromatic aspect (Figures 1, 2).

Figure 1: On the left Pietraforte as building material of Pitti Palace. Figure 2: on the right an ornamental detail of the facâde. The aim of this work has been to characterize (both from a geological and petrographical point of view) the Florentine Pietraforte and to study the decay phenomenologies. Pietraforte is a sedimentary rock belonging to the turbidite formation present in the allochthonous External Ligurids complexes thrust on the Tuscany Series. In this specific case, the turbid current gave rise to the formation of typical convoluted laminations (Ricci Lucchi, 1970) (Figure 3). The formation is dated to the Late Cretaceous (Abbate & Bruni, 1987; Bortolotti, 1962). In the Florence area, Pietraforte is present in large lenses within the Sillano Formation. The thickness varies from several tens of meters to 800 m. From the lithological point of view, it is a regular alternation of silico-carbonate, turbidite sandstones and shales, with rare intercalations of more or less marly, carbonate layers. In sandstones, the silicate component generally has the same abundance as the carbonate one. The original calcite component of the matrix underwent recrystallization during diagenesis, constituting a very resistant binder. Pietraforte is defined petrographically as a lithic sandstone; the clastic granules consist of quartz, feldspars, fragments of low-grade metamorphic rocks, acidic effusive rocks and dolomitic rocks (Cipriani & Malesani, 1966; Bruni et al., 1994) (Figure 4).

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Figure 3: On the left, detail of convoluted laminations in Pietraforte. Figure 4: On the right, image in thin section in xpl of Pietraforte, showing the characteristic texture with calcitic binder. The sandstone is grey when freshly cut but easily undergoes a chromatic alteration, acquiring a warm ochre colour. This colour change, due to iron oxidation, proceeds very quickly from surface to interior without affecting the cohesion of the material (Malesani et al., 2003). Moreover Pietraforte shows fractures completely or partially filled with calcite (calcite veins), which can be zones of weakness and preferential separation. Water acts on these fractures both by dissolution of the calcium carbonate constituting the calcite veins and by freezing processes. In both cases, the discontinuities present in the rock are accentuated and flakes and blocks of material can fall off. Water can also act by dissolution of the stone’s carbonate cement, giving rise to intense intergranular decohesion as well as precipitation processes with the consequent formation of superficial crusts. It can also affect the clay minerals of the matrix, characterized by the presence of swelling minerals (illite-smectite and chlorite-vermiculite) (Banchelli et al., 1997), which expand and contract with thermo-hygrometric cycles causing superficial disintegration and exfoliation. The more ancient Pietraforte quarries were on the hills close to the left bank of the Arno River from Piazza Poggi to Piazza di Santa Felicita, Palazzo Pitti and the Boboli Gardens. It has been said of Palazzo Pitti that it was already underground because the quarries for its construction were beneath its foundations and it was merely sufficient to “turn it” upward to see it realized. A part of the Boboli Gardens was realized in the amphitheatres of the Pietraforte quarry, constituting an example of splendid ante litteram landscape recovery. A quarry was reopened in Boboli when there was the need of material to restore and rebuild the ancient Oltrarno towers after their destruction in 1944 during the Second World War. Other recently exploited quarries are at Campora, on the hills west of Porta Romana, which also provided the material for the Santa Maria Novella station, the work of the architect Giovanni Michelucci and considered a masterpiece of rationalist architecture, and in Monteripaldi, south of the city. In recent time the Pietraforte has been excavated in the quarries near Greve (Santa Cristina) and near Reggello (Riscaggio) which are still active. About the supply of material, investigation on Loggia dei Lanzi (a famous building on a corner of the Piazza della Signoria in Florence) has provided interesting information regarding the original quarries. The mineralogical study of the Pietraforte blocks revealed the presence of material from three different quarries (Boboli, Viale Galileo and Monteripaldi). In particular, the

32



stone of the upper part of the Loggia come from the Monteripaldi quarry, even though this quarry was opened at the end of the 15th century and the period of construction of the Loggia was the 14th century. This can be explained by the fact that the upper part of the building, being more exposed to atmospheric agents, is the one that has deteriorated more rapidly and thus has undergone periodic substitutions with material deriving from the Monteripaldi quarry. Extensive substitutions with material from this quarry have also been found in the pilasters facing the Uffizi Museum (Banchelli et al., 1997). Taking into account what previously exposed, it is clear that Pietraforte is a very important stone material for Florence. It is a relatively durable material but yet subjected to deterioration and in some cases, when the restoration intervention would be not effective, it is necessary to replace it. References ABBATE E., BRUNI P., 1987, Modino-Cervarola. Torbiditi oligo-mioceniche ed evoluzione del margine nord appenninico. Mem. Soc. Geol. It. 39, 19-33. BANCHELLI A., FRATINI F., GERMANI M., MALESANI P., MANGANELLI DEL FA’ C., 1997, The sandstones of Florentine hystoric buildings: individuation of the marker and determination of the supply quarries of the rocks used in some Florentine monuments”. Science and Technology for Cultural Heritage, 6 (I), 1997, 13-22. BORTOLOTTI, V., 1962, Contributo alla conoscenza della Serie Pietraforte-Alberese. Boll. Soc. Geol. It., v. 81, no. 2, 225-304. BRUNI, P., CIPRIANI, N., AND PANDELI, E., 1994, New sedimentological and petrographical data on the Oligo-Miocene turbidite formation of the Tuscan domain. Mem. Soc. Geol. It., v. 48, 251-260. CIPRIANI C., MALESANI P., 1966, Ricerche sulle arenarie: 13) La Pietraforte. Boll. Soc. Geol. It., v.85, no. 2, 299-332. MALESANI P., PECCHIONI E., CANTISANI E., FRATINI F., 2003, Geolithology and provenance of the materials of the some historical buildings and monuments of Florence centre (Italy). Episodes, Vol. 26, n. 3, 2003, 250-255. RICCI LUCCHI F., 1970, Sedimentologia. Atlante fotografico delle strutture primarie dei Sedimenti. Zanichelli Editore, Bologna, 1970 Keywords: Pietraforte, characterization, decay, substitution.

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ITAQUERA GRANITE IN SÃO PAULO CITY, BRAZIL

E. A. Del Lamaa*, M. H. Barros Oliveira Frascáb

aInstitute of Geosciences, University of São Paulo: Rua do Lago n. 562, São Paulo, SP, Brazil,

05508-080; b MHB Geological Services, São Paulo, SP, Brazil * Corresponding author [email protected]

Introduction When the small village of São Paulo de Piratininga, which already held the status of municipality as early as the 18th century, started to develop into what is nowadays São Paulo City, Itaquera Granite was the main building stone available and was used in the oldest monument in the city, the Obelisco da Memória (Memory Obelisk), inaugurated in 1814 (Figure 1).

Itaquera Granite Itaquera Granite is a finely-grained gray biotite monzogranite, and it has a slightly oriented structure with sparse small micaceous enclaves or K-feldspar aggregates (Figure 2). The origin of this rock is associated with the Neoproterozoic granitic intrusions found in the São Paulo State (Figure 3), which represent the tectonic events related to the formation of the West Gondwana. These granites are inserted in the crystalline basement that outcrops in the southeastern part of the state.

Figure 1. Memory Obelisk: the oldest monument in São Paulo City.

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Mapping carried out in the old center of São Paulo City shows the use of this granite in at least 50 buildings, with emphasis on Municipal Theater, Metropolitan Cathedral, São Bento Monastery, São Francisco Church, Carmo Church, Law School of the University of São Paulo, Pinacoteca, entrance portal of Consolação Cemetery, Ramos de Azevedo Monument, among others (Figure 4). From this survey it was inferred that Itaquera Granite was used from the beginning of the 19th century to 1940s. There are no official records about the exploitation of Itaquera Granite during the 19th century, but the granite used as a foundation as well pavement, flooring and cladding of the historical buildings of São Paulo came from the Roque Quarry (represented by number 1 in Figure 3) where it was extracted manually. It was not until the inauguration of the Municipal Theater in 1911 that one could find information about this granite, when a brochure listing the provenance of all the rocks used in its construction was provided.

Figure 3. Granitoid rocks in the Southeast of São Paulo State (Del Lama et al. 2015).

Figure 2. Itaquera Granite. A. Bush-hammered finish. B. Faulted micaceous

enclave. C. K-feldspar aggregate.

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The production of crushed stone using this granite started in 1957, when the name of the quarry was changed to Itaquera Quarry, and continued until to 1999. In 2006 the cave of the old quarry was filled up and is now ready to urbanization, which make very difficult to obtain stone material from there for restoration. The quarry had a long history of strong relationship with the local community, housing wedding ceremonies and popular parties (Figure 5). Conclusions In Brazil, the use of stones in historical buildings and monuments was generally not so common. Regarding São Paulo City it can be said that Itaquera Granite is an important example of Heritage Stone Resource due to its local availability and use during the transformation of what once was a small village into the present megalopolis. In fact, it can be seen in the most traditional buildings of the city. Reference Del Lama E.A., Bacci D.D.L.C., Martins L., Garcia M.G.M., Dehira L.K. 2015. Urban geotourism and the old centre of São Paulo city, Brazil. Geoheritage, 7:147-164. Keywords: Itaquera Granite, São Paulo, building stone.

Figure 5. Popular party in Itaquera Quarry in 1967.

Figure 4. Historical buildings with Itaquera Granite. A. Municipal Theater.

B. Metropolitan Cathedral.

37



QUARRYING: VITAL ACTIVITY IN THE PAST, BANNED ACTIVITY IN THE

FUTURE?

L. Sousaa, J. M. Lourençoa,b, D. Pereirac*,

aUniversity of Trás-os-Montes e Alto Douro, Quinta de Prados, 5000-801 Vila Real, Portugal; bCentre for Mechanical Engineering, Materials and Processes, University of

Coimbra, Portugal; cDepartamento de Geología, University of Salamanca, 37008 SPAIN [email protected]

Introduction Raw materials are the main subject of many research programs at present (e.g. Horizon 2020). Within this subject quarrying has to be considered, as it is an activity that should evolve to meet the current standards for security, environment, health and other related issues. Many organizations and groups have the impression that quarrying activities, as well as mining activities, should be banned because they cannot guarantee complete adherence to all these standards, especially as they also undergo modification over time. However, it has been demonstrated that if extractive industries follow strict rules, they contribute to the advancement of modern society with minimal negative effect. Also, using local resources is important for the maintenance of the cultural heritage, both geological and architectural, by preserving the quarrying and mining landscape and by using the same natural stones that were used to build the monuments and historical buildings. The city of Salamanca is a particularly instructive case for all these matters. It was designated as a UNESCO World Heritage Site in 1988 and one of the reasons was the homogeneous architecture, using local natural stones (e.g. the golden sandstones from Villamayor, the siliceous conglomerate from Salamanca´s own bedrock, and from the surrounding region the tourmaline-rich granite from Martinamor (Pereira et al. 2015). A conscious effort has been made to maintain and preserve the historical buildings, but sometimes restoration has not been the best option, largely due to the lack of information on the original materials. The International Union of Geological Sciences (IUGS) Subcommission on Heritage Stones (HSS) has been striving to encourage the dissemination of information on the original natural stones used in the construction of the historical city and also in the need for preservation of historical quarries so that restoration can be done with original stone. This subcommission has triggered a specific standard related to stones called Global Heritage Stone Resource (Cooper et al. 2013). The stones quarried in the Salamanca area could be excellent candidates for this recognition. Together could also be candidates to the figure Global Heritage Stone Province. Learning from the past, looking to the future. One of the most important features of Salamanca that led to it being designated a World Heritage Site is the homogeneous and remarkably well preserved constructions using locally extracted stones ranging from sandstones to granites, albeit under different architectural styles through centuries. The most characteristic stone used in most of the foundations of the historical buildings in the centre of the city is a leucogranite containing clusters of elongate tourmaline crystals, a fabric that inspired the local quarrymen to give it the name of Piedra Pajarilla (Pereira

39



and Cooper, 2013; Pereira et al., 2015). The quarries are some 15 km south of Salamanca (Figure 1), in the outskirts of Martinamor village (Figure 2), which gives the formal name to the granite.

Figure 1.- Studied area. Modified from Díez Balda, 1986.

Figure 2.- Locations of mines and quarries in the study area.

This granite has been proposed as a Heritage Stone (Pereira et al. 2015) and along with the other kinds of stones that crop out in the province and are used in historic buildings of Salamanca, have been proposed as a Global Heritage Stone Province (Pereira and Cooper 2014). For this reason, this resource should be preserved and the quarries maintained, kept both in reserve for restoration but also for outreach and education. At present there are three main quarries outside Martinamor. One is on private land where cattle are kept. Another two are on public land. So far, these quarries are well preserved. There are even some vestiges of earlier quarrying methods, which are similar to those observed in ancient Egypt and prehistoric sites in Europe and South America (http://www.ancient-wisdom.com/quarrymarks.htm). These marks are due to tools used to separate the blocks, both in the vertical and in the horizontal plane. The granite is affected by a homogeneous system of fractures, and quarrymen took advantage of them to facilitate extraction. Analysis of the fracture pattern can be easily carried out using drone images. We are doing this in order to investigate whether it would be feasible to use some of the blocks for restoration of monuments and historical buildings in Salamanca, because it has been observed that in some cases blocks have been replaced by other types of granite. This means that the aesthetic effect is inappropriate for an historical site, especially for a World Heritage Site. The study of fractures has proven to be a useful method to discern whether a sufficient quantity of dimension stones can be extracted from a quarry (Sousa 2007) and whether the fracturing can be exploited in the extraction process, facilitating the quarrying and therefore lowering cost (Figure 3).

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Figure 3.- Aerial view of an outcrop of the Martinamor granite and the main direction of fractures.

Conclusions Scientific research can show how past mining and quarrying activities have been carried out but also how they can be part of the very much needed new endeavours. Traditional geological methods like mapping and petrology contribute to the understanding and preservation of historical natural stone quarries that were used to build the architectural heritage of so many societies. New technologies however, like aerial imaging using drones, can show the different possibilities of taking advantage of historical mines to use the leftover tailings in resourcing future generations. It is important to recognize that education and outreach are very important to maintain the knowledge of past mining and quarrying traditions that are part of the cultural heritage and to remind people that these are positive activities that are vital for the advance of modern societies. Acknowledgements Research is part of a program funded by the following institutions: Fundación Universidad-Empresa, the Castilla y Leon regional government and the University of Salamanca. It is also part of the activities of the UNESCO IGCP-637. References Cooper, B., Marker, B., Pereira, D. and Schouenborg, B. (2013) Episodes vol. 36-1, 8-10. Díez Balda, M.A. (1986) Ediciones Universidad de Salamanca, 162 pp. Pereira, D., Gimeno, A. and del Barrio, S. (2015) Geological Society Special Publications, 407, 93-100. Pereira, D. and Cooper, B. (2014) Geological Society Special Publications, 391, 7-16. Sousa, L. (2007) Engineering Geology 92, 146-159. Keywords: Quarrying, natural stone, geoheritage, UNESCO World Heritage site

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INDIAN CHARNOCKITE: A POTENTIAL GLOBAL HERITAGE STONE

V. K. Sharma* and B. J. Cooper**

* Engineering Geologist, Bihar Vikas Mission, Government of Bihar, Patna, India

** Professor, University of South Australia, Adelaide, SA 5001, Australia ([email protected])

Introduction The use of the rock, charnockite, for monuments as well as for construction and architectural use is as old as civilization. Charnokite may be broadly defined as a granitoid, primarily composed of Quartz-Alkali Feldspar-Plagioclase but typically also containing Orthopyroxene (Hypersthene). It is typically characterized by a dark green, greasy lustre. Among the widely distributed heritage rocks of India, charnockite had a distinctive position with historical importance even attached to the name itself. The rock was first named by Holland (1900) to honor Job Charnock who is credited with founding of the city of Kolkata. The rock for the tombstone of Job Charnock, in St. John’s Church in Kolkata, is made of charnockite sourced from distant St. Thomas Mount, at Pallavaram, a suburb of Chennai in Tamil Nadu State. In 1975, the Geological Survey of India declared the type locality of charnockite at St. Thomas Mount as a National Geological Monument. Indian Charnockite Charnockites typically form in deep continental crust and are commonly found in metamorphic terrains of granulite facies. The rock belongs to a broader group of granites, yet have been ascribed diverse origins, spanning a range of metamorphic and igneous derivations exhibiting compositional and colour variations. Typical occurrences of charnockites have been reported from various granulites terrains of the world notably - Sri Lanka, South Africa, Brazil, Antarctica, Australia, Canada and the Nordic countries etc, as well as southern India. However, Indian Charnokite has a cultural significance and utilisation that is greater than charnokite from other countries. Groups of monuments at Mahabalipuram in Tamil Nadu (Fig.1), India built by Pallava kings in the 7th and 8th centuries have been carved out of charnockite and granites sourced from along the Coromandal coast of India. The temple town has about forty monuments including the largest open-air rock relief in the world. The rock-cut monuments are now a UNESCO World Heritage site. Besides, charnockites have also been used widely in sculptures and the superstructure of several temples in India as well as in several monuments overseas. An international sculpture that records the usage of charnockite is the Oscar Wilde memorial monument, Dublin, Ireland, constructed in 1997. Since charnockite was first identified inIndia, and named after an interesting historical event, its widespread usage in manycountriesanditsapplicationinmanyheritagebuildings,therockmaywellbeacceptedas

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theGlobalHeritageStone.TherockisactivelyfrommanygranitequarriesfromsouthernIndia.

(a) (b)

Figure 1 (a) Groups of monuments at Mahabalipuram in Tamil Nadu - UNESCO World Heritage site (b) Shore temple on Coromandel coast using charnockite in architectural edifice

Conclusions The geotechnical properties of charnockite transform the rock into a versatile dimension stone amenable to architectural use. Indian Charnokite is here recommended as a potential candidate for Global Heritage Stone from India given its history, cultural prominence and value both in construction and sculpture as revealed in numerous monuments. Keywords: charnockite, orthopyroxene (hypersthene) granites, dimension stone, heritage

monuments, Job Charnock

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GEOHISTORICAL INFORMATION TO BE DERIVED FROM BUILDING STONES – THE PORTLAND LIMESTONE CASE STUDY

M. Brocxa*, K. Pageb, V. Semeniukc

aEnvironmental and Conservation Sciences, Murdoch University, Western Australia, 6150; bUniversity of Plymouth, Plymouth, UK; cV & C Semeniuk Research Group, Glenmere Rd.,

Warwick, Western Australia, 6024; *Corresponding author [email protected]

Introduction Limestones are used in a variety of ways as building stones and, as cut and polished surfaces, they provide a wealth of geological information for use in geo-education, particularly for geological history, processes, and products. This paper highlights the usefulness of building stones to researchers, geotour operators, and the general public, using the Jurassic Portland Limestone as a case study. Use of the Portland limestone (also known as Portland Stone) is particularly appropriate as it was designated as a Global Heritage Stone Resource (Hughes et al. 2013; Episodes Special Issue 2015). Description of the Work The Portland Limestone of the Dorset Coast, UK has been utilised in buildings and walls in varying sizes in a variety of ways, viz., roughly-hewn to neatly-cut building bricks, stone walls, polished building facades, rough-cut large building stones, paving stones, and edging to stone walls. The limestone lithologies include (1) massive (structureless) lime mudstone, (2) bioturbated and Thalassinoides-bearing lime mudstone, (3) interlayered lime mudstone and shelly lime mudstone, (4) thin-bedded to thickly bedded shelly lime mudstone, (5) shelly limestone now with mouldic porosity, (6) oolitic limestones, and (7) cherty limestone. Palaeo-environmentally, the lithologies and fossils record deposition in lime mud environments (with burrowing fauna) and in oolitic environments, and a changing skeletal fauna reflecting varying depth and climate. The limestones also are leached developing spectacular mouldic porosity. Quarried blocks of limestone, chert in limestone, the various uses of the limestone, and some examples of the lithologies (such as the fossil content, various bioturbation structures, effects of burrowing on sediment and shells, and diagenesis) are illustrated in Figures 1-10. The best examples of Portland Limestone in building stone, particularly in public places, can be utilised as educational sites for the public and for professional geologists by providing descriptive and interpretative signage highlighting facets of lithology, palaeo-environments, and fossil content. Essentially, the signage accompanying the slabs and bricks of rock would act as the pages of an illustrated encyclopaedia on the Jurassic limestones of Dorset. This would highlight the geoheritage of the Dorset region to the local communities, tourists who visit the area and, globally, where the limestone has been exported. As such, we highlight the diversity of geological features in the Portland Limestone and suggest protocols whereby geohistorical information derived from building stones can be used locally and globally to promote geoheritage and geological education.

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Conclusions The Portland Limestone presents a rich resource of geological information in terms of lithologic variation, palaeo-environments, palaeo-ecology, and diagenesis, all of which can be utilised via signage and brochures for raising geological consciousness of the public and geologists, and highlights the extent that geohistorical information can be embedded in the geoarchive of building stone. The principles outlined here can be applied to other types of building stones occurring elsewhere globally. References Hughes T, Lott G K, Pouoltney M J & Cooper B J 2013. Portland Stone: A nomination for ‘Global Heritage Stone Resource’ from the United Kingdom. Episodes: 36: 221–226. Cooper B J 2014. The 'Global Heritage Stone Resource' designation: past, present and future. Geological Society London Special Publications 407: 11-20.

1. Blocks of Portland Limestone in quarry

2. Chert nodule Portland limestone in quarry

3. St Pauls Cathedral London, constructed with Portland Limestone

4. Bricks of Portland Limestone, Chesil Beach Centre

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5. Ornamental dry stone wall of Portland Limestone bricks, Chesil Beach Centre

6. Bricks of Portland Limestone in wall showing lithologic variability

7. Portland Limestone bricks: shelly limestone (now mouldic) and massive limestone

8. Portland Limestone: shell hash in limestone overlying bioturbated limestone

9. Prominent burrows in bioturbated limestone

10. Mouldic porosity in the limestone

Acknowledgements: Funding by IGCP-637 and VCSRG R&D12 are gratefully acknowledged. Keywords: Portland Limestone, building stones, geoheritage, geological history, geotrails.

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BUILDING STONES - A PROTOCOL TO RAISE PUBLIC CONSCIOUSNESS

M. Brocxa*, V. Semeniukb

aEnvironmental and Conservation Sciences, Murdoch University, Western Australia, 6150;

bV & C Semeniuk Research Group, Glenmere Rd., Warwick, Western Australia, 6024; *Corresponding author: [email protected]

Introduction Building stones are recognised as heritage features culturally, historically, archaeologically, architecturally, and aesthetically, and there are a growing number of building-stone tours and self-guided walks in major cities and towns worldwide. However, too often, building stones that are of iconic rock types are viewed simply as decorative stone or pathways without explanation of the richness of geological information they contain. Description of the Work While there are building stone tours worldwide, we consider the building stones have been under-utilised as a resource in terms of Geoheritage, Geo-education, and geological consciousness-raising of the resident public and visiting tourists. Building stones, if derived from local quarries and accompanied by signage, can provide the public with a sense of place, and effectively create an outdoor urban museum of the local geoheritage and geodiversity. Building stones, if derived from elsewhere globally, if accompanied by signage, again, provide the public, scientists, and geologists (and geology students) with a window into the geodiversity of rock types occurring worldwide. Building stones accompanied with signage thus can function as pages of a text book explaining rock types, rock origins, and the history of the Earth. The following protocols are recommended to raise the consciousness of the public, geologists, and students regarding Earth history and geoheritage using buildings stones: (1) inventory undertaken by a local government authority of the most iconic polished or cleanly-hewn stones in public places in a given city/town; 2) prioritise the building stones in the inventory for further work on signage, but selecting the best examples of igneous, sedimentary, fossiliferous, and metamorphic rocks; (3) design a trail or walk taking the public, students, and tourists to each of the building stone sites that have accompanying signage; 4) research, then draft information for use in signage, or brochures, or “apps” for each of the selected rock types; (5) design explanatory small-scale signage of the most iconic building stones for on-site display in public places; the text of the signage/brochures can be at multi-levels to accommodate students and the public; the example of text in the accompanying Figure is oriented towards university students; (6) display of brochures and the availability of heritage stone tour “apps” in tourist information centres. Conclusions Educational utilisation of building stones using signage, brochures and heritage “apps” can raise the profile of the Earth Sciences and Geoheritage, and introduce school and university students, the public and tourists in an outdoor museum-like setting to the significance of building stones and to the history of the Earth, based on the locally-derived material or iconic overseas materials.

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Polished stone (from Brocx & Semeniuk 2018)

Examples of style of text for plaques or signage that could accompany decorative

stone on walls or walkways

This natural building stone is an unusual 2.6-billion-year-old rock called orbicular granite from Mt Magnet, Western Australia. The rock shows orbicules with prominent concentric structure and radial crystal structure. Orbicular granite occurs on all continents but is not common, and no two orbicular granite occurrences are alike.

This natural building stone is a brecciated serpentinite from the quarries of Cesana, Torinese Piedmont, Italy, and is a common building stone used throughout the world. Serpentine is composed of the serpentine group of minerals. This particular serpentinite is fractured with a 'crazed' pattern of calcite veins or talc-schist

Persian Red Travertine from Iran is the most famous of the travertines, valued for its use as an ornamental stone and its natural history. The travertine is a calcium carbonate rock composed of algal precipitates (as laminations and fronds); this slab shows a lower massive form riddled with rootlets, and an upper part of branching calcareous fronds

Acknowledgements: Funding by IGCP-637 and VCSRG R&D12 are gratefully acknowledged. Keywords: building stones, geoheritage, geodiversity, building stone trails, geological signage.

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STEATITES OF BRAZIL AS CONTENDERS FOR THE GLOBAL HERITAGE STONE RESOURCE

A. G. Costaa*

aLABTECRochas - Federal University of Minas Gerais, Brazil Av. Antônio Carlos, 6627, Belo Horizonte, Minas Gerais, Brazil, 31270-901

*[email protected] Introduction In Brazil, European natural stones, such as marble and limestone, were used as building material at historically important buildings and monuments, mainly in coastal cities, as well as in contemporary urban centers. However, in the country’s central region, these Italian and Portuguese marbles and limestones were rarely used because of their financial cost (due mainly to transport). Instead, they were substituted by local steatites. From the mid-eighteenth century, at the top of gold production in the former Portuguese colony in the Americas, steatites were used at historical buildings in the Brazilian inland, especially in constructions in Minas Gerais towns. They were employed because of the ease workability. Historical applications for steatites in Brazil Between the end of the seventeenth and the nineteenth, steatites, and to a lesser extent serpentinites, were used in the production of ornamental pieces, coating and sculptural art present in Minas Gerais. This use was due to the absence in those historic cities of good quality limestone, usually used for the production of decorative elements and statues. Steatite was available and had suitable properties for these uses. Because of their local occurrences and the frequency with which steatites (soapstone) were used, they were known as "stone of Minas Gerais (Pedra de Minas)" and among these applications worth highlighting the sculptural group formed by twelve life-size statues, representing the prophets of the Old Testament. Sculpted by Aleijadinho, these are exposed in the churchyard of the sanctuary of Bom Jesus de Matosinhos, in Congonhas (Minas Gerais). Steatites of Minas Gerais present in constructions of the cultural patrimony of the humanity in Brazil In Brazil, there are 13 Historical and Cultural Heritages of Humanity that have been registered by the United Nations Educational, Scientific and Cultural Organization (UNESCO). This collection includes archaeological records, ruins, buildings and monuments. In three of these heritage sites the steatites have been widely used mainly as decorative elements, as can be seen in buildings and monuments in two historical sites of Minas Gerais and in a very important monument of the city of Rio de Janeiro. In the city of Ouro Preto (Minas Gerais), the architectural and urban complex of the old Vila Rica was declared a world heritage site in 1980. In this city, which is the first Brazilian cultural object inscribed on Unesco's list, there are many applications for steatite. A second case is in the city of Congonhas, another city of Minas Gerais, where in the eighteenth century was built the sanctuary of Bom Jesus de Matosinhos, one of the main masterpieces of the world baroque, recognized by UNESCO in 1985. The ensemble is formed by the church, in rococo style, churchyard with external monumental staircase decorated with statues of 12 prophets in steatite (Fig. 01) and six chapels illustrating the Via Crucis of

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Jesus Christ. A third use of Minas steatite is in the city of Rio de Janeiro. It was used in the outer casing of the statue of Cristo Redentor.

Figura 1: Sculptural set exposed in the churchyard of Bom Jesus sanctuary in Congonhas, Minas Gerais. The images were sculpted in steatite in the workshop of master Aleijadinho, in the early years of the 19th century (Photograph: A. Gilberto Costa). Geology and location of the most important areas of steatites extraction in Brazil In Brazil, the most important areas of steatite extraction are located in the state of Minas Gerais. There are no records for other areas of importance or expression out of state. These areas are associated with both rocks of metamorphic complexes, whose gneisses, amphibolites and granites are older than 2.8 Ga, and those of the Rio das Velhas Supergroup, which consists of phyllites, schists, quartzites, metavulcanic rocks and iron formations, with ages around 2.8 Ga. They present metamorphic parageneses typical of greenschist facies and in addition to talc, contains different content serpentine, chlorite and amphibole. The main occurrences and historical areas of steatite extraction are found in areas in the municipalities of Ouro Preto (Santa Rita de Ouro Preto: 20º34'12,27"S / 43º29'0,25"W, 20°32'18.8"S / 43°32'41.1"W, 20°34'16.47"S / 43°28'37.46"W), Congonhas (20°30'39.8"S / 43°50'20.7"W) and Mariana (Cachoeira do Brumado: 20º23'05,42"S / 43º14'10,12"W). Conclusions Taking into account the use of steatites in monuments that are part of the Cultural Heritage of Brazil and which are recognized as elements of the Cultural Heritage of Humanity, it is justified that this rock of Minas Gerais be recognized contenders for the Global Heritage Stone Resource. Keywords: Steatite, Heritage, Brazil

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“TRACHYTES” FROM SARDINIA: GEOHERITAGE AND CURRENT USE

N. Careddua*, S. M. Grillob

aDepartment of Civil, Environmental Engineering and Architecture (DICAAr), University of

Cagliari, via Marengo 2, Cagliari, Italy, 09123; bDepartment of Chemistry and Geology (DSCG), University of Cagliari, via Trentino 51, Cagliari, Italy, 09127

*Corresponding author Email Address: [email protected]

Sardinia was affected by an intense igneous activity which generated calc-alkaline products during the Oligo-Miocene era. The volcanic products show large variations, ranging from pyroclastic flow deposits, lava flows and domes. By composition they are primarily dacites and rhyolites, with subordinate andesites and very scarce basalts. The rhyolite lavas show porphyritic and ash-flow tuffs. Ignimbrite structures are found in the dacitic domes and rhyolitic lavas. These rocks, commercially known as “Trachytes of Sardinia”, used to be quarried in all historical provinces, mainly in the central part of the Island to be used as ornamental and building stone. They continue to be commonly used nowadays, although their use dates back to the prehistoric age. They are easily found in many nuraghi, “domus de janas”, holy wells, Roman works (mosaics, paving, roads, bridges), many churches built in Sardinia and practically in all kinds of structural elements in public and private buildings, such as walls, houses, and bridges. Figs. 1 and 2 show two examples of buildings (ancient and modern) in which Sardinian trachytes are used. Contrary to the granitoid rocks whose appearance is largely influenced by the mineralogical composition, the aesthetic feature of volcanic rocks is rather affected by the widest range of their colours, structure and texture, i.e. shape, size and distribution of mineral components, porphyric index”, etc. Some examples are shown in Figs 3 from a to h. Trachyte is quarried opencast with the “single low step” method, with descending development, with prevalent use of double-disc sawing machines. Whenever the stone deposit allows higher steps, the chain cutting machine, in combination with diamond wire, becomes the preferred extraction solution. After a geological-petrographic framework, the paper discusses the historical uses of trachyte in Sardinia. The current state of the art of trachyte quarrying, processing and usage in the Island is also described. An analysis of the trachyte production has been carried out (some data are shown in Table 1). Table 1. Sardinian “trachytes” and tuffs (used as ornamental stone): official quarrying production

in 1999-2017 (in m3).

1999 2002 2005 2007 2012 2014-17 5,240 13,195 19,950 12,013 15,900 111,685

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Figure 1. The Church of San Pietro extra muros in Bosa (north-west Sardinia, XI-XIII centuries).

It was built in Romanesque style by using various shades of pink and red rhyolites.

Figure 2. A detail of Teatro Massimo in Cagliari (south Sardinia). The cladding, in a “run”

pattern with runs in variable heights, is built in Fordongianus red trachyte.

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Figure 3. Some examples of “trachytes” from Sardinia: a) Pietra di Serrenti; b) Fordongianus red

trachyte; c) Fordongianus green trachyte; d) Carbonia-Perdaxius trachyte; e) Ittiri yellow trachyte; f) Ozieri trachyte; g) Bosa trachyte; h) Montresta red.

Keywords: trachytes, Sardinia, geoheritage, dimension stone, market.

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BALMA SYENITE (CERVO VALLEY – BI, NORTHERN ITALY): A NEARLY UNIQUE MATERIAL WHICH COULD BE DESIGNATED AS HERITAGE STONE

F. Gambino a*, A. Borghia, G.A. Dinoa, P.G. Rossettia, D. Castellia

a Dipartimento di Scienze della Terra - Università di Torino, Via Valperga Caluso 35, 10100, Torino, Italy; *[email protected]

Introduction In the Piemonte region (NW Italy), stone has always been the most widely used in historical, contemporary palaces and monuments, characterizing the close connection between architectonic and cultural history of Torino (Piemonte capital) and its surroundings. Among the intrusive rocks present in the Western Alps, the Balma Syenite have to be noticed. It is an uncommon, nearly unique, material which represents a small post-metamorphic intrusive bodies of Oligocene age, intruded in the eclogitic micaschist complex of the Sesia Lanzo Zone belonging to the Austroalpine domain and outcropping respectively along the Cervo Valley (Biella) and the Chiusella Valley (Canavese) (Fig. 1). Characterization of the Balma Syenite The Balma Syenite pluton outcrops few kilometers North of Biella, in the Southern foothills of the Alps, occupying an area of about 35 km2. The pluton is compositionally zoned and consists of monzogranitic rocks in the core surrounded by a discontinuous portion of syenitic rocks and, finally, by a wide rim of monzonitic rocks. The Balma Syenite (Fig. 2) shows a typical grey-violet color, medium grain size and a well developed magmatic flow fabric. Its mineralogical composition consists of violet potassium feldspar crystals showing Carlsbad twinning and perthitic exsolutions, which mainly influences the typical colour of the rock, with lesser amounts of plagioclase and very low content of quartz. Amphibole and biotite occur among the femic minerals. Sphene is the distinctive accessory mineral; the others are apatite, zircon and ores (Fig. 3, 4). Two varieties of Syenite della Balma are recognisable: the sphenic one, characterized by well crystallized minerals with wedge shape, which guarantee high compressive strength and good physical characteristics (Table I), and the porphyric one, characterized by the presence of big feldspar crystals, easily alterable with consequent decrement of the physical characteristics. Currently there are two active quarries, both present in San Paolo Cervo area (Fig. 1), and ten abandoned quarries located in the area within the villages of Rialmosso, Piedicavallo, Balma, Campiglia Cervo, Rosazza and Oropa. The first quarrying activities are referred to 1830, when the local quarry man exploited the column (7 meter high) employed for the Consolata church in Torino. After that, employing very simple working processes (handcrafted processes), the local quarry man started to exploit Syenite in a more organized way. Thanks to these peculiar characteristics the Balma Syenite has been largely applied, from XIX century, for internal and external purposes: - At local and regional level: villages, roads, bridges, banks, etc. present in Cervo Valley and

in Biella and for the columns of the Consolata church, the basement of the Carlo Alberto equestrian statue, the columns in Via Roma (San Damiano block) (Fig. 5), Emanuele Filiberto Duca d’Aosta Monument in Torino (Fig. 6);

- At National level: the monuments to Garibaldi and to the “5 days of Milano”, the columns for the BCI (Italian Commercial Bank), the façade of the Casse Lombarde palace in Milan;

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the columns of Termini railway station and the monument to Quintino Sella in Rome; the columns of the Exchange Palace in Naples;

- At international level: the four columns (8.45 meter high and 1 meter of diameter) for the Notre Dame cathedral in Lyon (1879); the façade of one of the main bank in Santo Domingo Republic.

Conclusions Considering the present knowledge about this material (from the characterization to the applications), we can say that the Balma Syenite can be designed as Heritage stone.

Figure 1 Quarry district of Balma Syenite Figure 2 Macroscopic aspect of Balma Syenite

Figure 3 Microscopic aspect of Syenite, only polarizer, amphibole (Amp) and titanite (Spn) are indicated

Figure 4 Microscopic aspect of Syenite, crossed polarizers, K-feldspar (Kfs), plagioclase (Pl) and amphibole (Amp) are indicated

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Table I: Balma Syenite main phisical characteristics PHYSICAL

CHARACTERISTIC MISURE UNIT VALUE

Apparent density kg/m3 2694 Simple compressive strength kg/cm2 2428

Compressive strength after freezing and thawing

kg/cm2 2094

Indirect Tensile Strength (Brasilian test)

kg/cm2 158

Water absorption % 0.29

Knoop microhardness MPa 4.650

Figure 5 Emanuele Filiberto Duca d’Aosta Monument in Balma Syenite

Figure 6 San Damiano block in Via Roma, in Balma Syenite

Keywords: Balma Syenite, Heritage stone, ornamental stones.

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A CLOSER LOOK INTO LIMESTONE SCULPTURES’ DEGRADATION FROM THE

PORTUGUESE NATIONAL MUSEUM OF ANCIENT ART

L. Diasa,b*, T. Rosadoa, A. Candeiasa,b, J. Mirãoa,c, A. T. Caldeiraa,b,

aHERCULES Laboratory, University of Évora, Largo Marquês de Marialva, 8, 7000-089 Évora, Portugal; bChemistry Department, Sciences and Technology School, University of Évora, Rua Romão Ramalho 59, 7000-671 Évora, Portugal; cGeosciences Department, Sciences and Technology School, University of Évora, Rua Romão Ramalho 59, 7000-671 Évora, Portugal; *[email protected]

Introduction Throughout history, stone has been the material of choice for cultural heritage because of its durability and beauty. Like all materials, stone is subject to inexorable deterioration mechanisms, that can be caused by several factors, either external or internal. The main degradation promotors which may easily affect indoor limestone are soluble salts, water and biodeteriogenic agents that can induce physical and chemical deterioration, leading to the loss of sculptor’s original intention. Materials and Methods Four limestone sculptures dated from the 15th and 16th centuries, belonging to the National Museum of Ancient Art in Lisbon, Portugal, present two different types of pathologies affecting their chromatic characteristics, with the appearance of white and red stains (Fig. 1), in addition to the loss of some original material. In this work, material analysis and microbial assessment of limestone sculptures were performed with the main purpose of identifying the particular features of the stones, as well as, the factors leading to their degradation. Micro-X-ray diffraction and SEM-EDS spectroscopy techniques were used to obtain the mineralogical composition of the material and to detect and characterize the alteration products. On the other hand, Next Generation Sequencing technology was applied to characterise the microbiota thriving on these sculptures.

Figure 1: Degradation patterns detected on limestone sculptures subjected to the study. St. John

the Baptist (a), The Virgin and Child (b), St. Paul (c) and Musician Angel (d).

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Conclusions Preliminary results demonstrate that the white staining and loss of material are related with the formation of efflorescences (Fig. 2) and could be a consequence of the weathering of iron sulfide minerals detected on the stone material (Fig. 3) or even the surrounding environment. On the other hand, the reddish stains found on the St. Paul and the Musician Angel sculptures could be correlated with the formation of some iron oxide compounds, namely hematite and hydrohematite, as secondary alteration products.

Figure 2 – Micro-X-ray diffraction of microsamples of the sculptures St. John the Baptist (____)

and The Virgin and Child (____).

Figure 3 – SEM micrographs of iron sulphide minerals in euhedral form found in microsamples

from the St. John the Baptist sculpture.

Microanalysis (Fig. 4) and high-throughput metagenomic approaches, allowed the detection of biocontamination on the altered stone surfaces. High-throughput Sequencing technology analyses showed that the main population present on the sculptures is prokaryotic belonging to the Streptococcaceae family. Results suggest that the biological agents proliferation could be involved in the alteration processes, increasing the degradative effect.

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Figure 4 – SEM micrographs of microsamples of the St. John the Baptist and the Musician Angel

sculptures, evidencing the proliferation of hyphae of filamentous fungi around calcite crystals.

Figure 5 – Representative characterisation of the prokaryotic population at family level present

in the limestone sculptures. Keywords: Sculpture, limestone, staining, degradation, biocontamination.

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A WALK IN A STONE VILLAGE IN MADONIE MOUNTAINS (SICILY, ITALY):

PETRALIA SOTTANA (PA) URBAN GEOTOUR F. Torre a, G.A. Dino b,*, A. Torre a, M. Dino c

aL. Fabio Torre & Alessandro Torre – Studio Associato – Geologi O.R.G.S. C/da

Paratore s.n.c. 90027 Petralia Sottana (PA), Italy bEarth Sciences Department – University of Torino (Italy, Via Valperga Caluso 35,

10125, Torino, Italy. *[email protected], Retired

Madonie mountains (Sicily) consist of mesozoic-tertiary carbonatic, calcareous-marl and silico- clastic rocks referable to the Sicilide, Imerese, and Panormide domains, as well as to the deposits of the Numidic Basin. These stone materials have been largely employed to build villages and infrastructures present in the Madonie nearby. A village – Petralia Sottana (Palermo District) – is particularly interesting and appreciable for the wide use, as in the past and at present time, of dimension and ornamental stones quarried in the Madonie area. In the Petralia area organic limestones, such as "Porites" and "Tarbestrallea" (bio-constructive corals, pertaining to the “Terravecchia” group, Tortonian age) outcrops. They appear yellowish-white in colour, vacuolar and characterized by good physic-mechanical characteristics; they are poorly banded and show evident signs of fossils and karst phenomena. Petralia Sottana (Petralilium, which means “lily made of stone”, and also Petra polis, which means stone village. Fig. 1) can be defined as an open air museum, nearly completely made of stones; a window which links past to present, in which it is possible to appreciate the large number of fossiliferous limestones representing the ancient basement of the ocean, once present in the Mediterranean area. The past is represented by the presence of stone workers, who worked in Petralia Sottana from Medieval age (probably connected to San Miceli church construction by Cistercian monks), to the XVII-XVIII centuries (coming from Trapani to work on the Dome, churches and palaces), and up to the mid-end of XX century (stone worker family, named Librizzi, coming from Palermo). But also the past linked to the origin of the Mediterranean Area: indeed, the Madonie mountains are a key point for the reconstructing the geological setting of the Mediterranean area in the last 200 million years. All the rocks present in the Madonie were formed in the bottom of the ocean and were subsequently deformed during the approach of the African and European plates, which caused the shortening of the Earth’s crust and gave rise to the Apennine-Maghrebide chain (Madonie mountains are part of the Meghrebide chain). The present is represented by the contemporary technicians, scientists and academics which invested time and effort in studying and promoting the beauty of the area: indeed, the studies of the large variety of fossiliferous rocks well preserved and visible in the area, their origin and evolution were fundamental in 2001 for the designation of the Madonie Mountains as GEOPARK (Madonie Park). Furthermore, this dynamic context led in 2011 to the creation of the Urban Geological Path (Geotour) of Petralia Sottana, an interesting and fascinating path, which twists and turns in the main road (Corso Paolo Agliata) and in the narrow alleys present in Petralia, in which geology, art and heritage. Following the indicated path (or creating a personal one) it is possible to walk on the Miocene fossils, meet corals on the portals of the houses and discover fountains and contact springs. Along a path, marked with brass studs, you can find local dimension stones employed, eg., for: the pavements of Corso Paolo Agliata (in which

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fossils in limestones are clearly visible) (Fig. 2); Petralia Dome, in which it is possible to appreciate fossils of the external elevation and monolithic columns made of Lumachella limestone (Fig. 3), quarried at “Vazu i Sant’Utieru” quarry site (Fig. 4); Saint Peter Church (coral fossils on the portal, Fig. 5); Appreciable chiselled fountains (U Canali, Fig. 6); etc... To complete this fascinating stone tour the tourist can visit the local Museum of the Geopark (Museum dedicated to the Geologist Giuseppe Torre. The peculiarity of Petralia Sottana is the direct link “from the quarry to the building” which characterized the area: moreover, the quarrying area (not yet productive) is part of a Geopark. Thus, Madonie mountains and Petralia Sottana can be recognized as a nearly unique sample of how Geoheritage (the Geopark) and heritage stones (the stones used to build Petralia Sottana village) can coexist, boosting the tourism of the area: for people interested in exploring the “open air Deep Sea” and for the ones interested in visiting villages, with local tradition and peculiar buildings, witness of the life in the Mediterranean see.

Figure 1. View of Petralia Sottana. Dome stands out against the peak of the village.

Figure 2. Fossils visible in the pavement of Corso Paolo Agliata

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Figure 3. Columns made of Lumachella limestones, inside Petralia Sottana Dome.

Figure 4. “Vazu i Sant’Utieru” quarry. Traces of fossils (shells) are clearly visible in red area.

Figure 5. Coral fossils present on the portal of Saint Peter Church

Figure 6. U Canali fountains

Keywords: Fossiliferous limestones, Stone tour, ornamental stones, Heritage stones

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VINDHYAN SANDSTONE: THE CROWNING GLORY OF ARCHITECTONIC HERITAGE FROM INDIA

G. Kaura*, P. Kaura, S. Garga, S. Singha, M. Panditb#, P. Agrawalc, A. Ahujad aDepartment of Geology, Panjab University, Chandigarh 160014, India; bDepartment of Geology, Rajasthan University, Jaipur, India; cDepartment of Geology and Mines, Govt. of Rajasthan, Bharartpur, India; dF-90D, Sec-57, SL3 Gurgaon, India

*Presenting author: [email protected] Indian architectonic heritage is manifested in form of palaces, forts, monuments, mausoleums, temples, mosques, etc. built from variety of stones covering a wide temporal and spatial extent. The locally available stones are usually favoured, however, the most spectacular stone that adorns umpteen architectonic heritage structures built from antiquity to the present is sandstone. Although sandstone occurs within a number of Proterozoic to Phanerozoic geologic formations, the Vindhyan Sandstone is the most favoured one. The Mesolithic age Bhimbetika rock shelters, a UNESCO world heritage site (https://whc.unesco.org/en/list/925), represents the oldest recorded use of the Vindhyan sandstone. The Buddhist architectonic and cultural heritage sites in form of monolithic pillars, temples and monasteries at Sanchi, Madhya Pradesh (also commonly known as the Sanchi Stupas), are the oldest (2nd B.C. to 12th A.D.) and built from Vindhyan Sandstones. The above mentioned architectonic heritages stand in all magnificence and glory that bear testimony to prolonged endurance against the vagaries of nature. Humayun’s Tomb, Tomb of Safdar Jung, Agra Fort, Red Fort, Chittorgarh Fort, India Gate, Rashtrapati Bhawan, Central Secretariat, Parliament Building, Buland Darwaza (gate) and mosque at Fatehpur Sikri, to name a few, are world acclaimed heritage monuments in the north-western India built in Vindhyan sandstone. Most of these architectonic heritage sites are also listed as UNESCO world heritage sites. The Vindhyan sandstones belong to Paleo-Mesoproterozoic-Neoproterozoic Vindhyan Supergroup that forms an E – W trending crescent-shaped basin-fill in the north-western and central India. It is one of the most extensive intracratonic basins and is stratigraphically divided into: the Semri Group (Lower Vindhyan); and the Kaimur, the Rewa and the Bhander Groups belonging to Upper Vindhyan. The common rocks comprising the Vindhyan Supergroup are: sandstone, shale and limestone. The Vindhyan sandstones, used extensively as dimension stones, belong to Bhander Group and are dominantly monomineralic with chemically resistant quartz as the main mineral. They are undeformed, unmetamorphosed and well bedded deposits. The sandstones generally exhibit a range of colours varying from dark red to brown, earthy buff, yellow, off white to spotted. The range of colours can be attributed to the nature of the cementing materials and oxidation state of iron oxide. The most popular amongst these is the red sandstone with ferruginous cementing material. It has been extensively used for building of architectonic heritage owing to its grandeur and strength. The red sandstone displays local variation in colour from light red to deep red and its various hues. The sandstone exhibits different patterns depending on the thickness of individual laminae/beds and the lateral continuity of the beds. The Vindhyan Supergroup alone is the major contributor of masonry sandstone reserves in India. The important quarries of Vindhyan Sandstone are located in Dholpur, Bharatpur, Kota, Sawai Madhopur, Tonk, Bundi, Jhalawar, Karauli and Chittorgarh in eastern Rajasthan.

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The central and eastern Indian occurrences of white, cream and red sandstone are known from Shivpuri, Panna, Rohtas, Keinjua and several other localities in Son Valley region. The Vindhyan Supergroup sandstones are widely known by numerous local trade names such as Agra red/pink, Dholpur red/pink/beige, Bansi pink, etc., after locality names of the quarries. The Vindhyan sandstone has been a favourite dimension stone since antiquity and is also quite popular in modern times. In contemporary times the Vindhyan sandstone has been put to numerous other uses such as garden furniture, sculpturing, carving, floor tiles, paving, cladding etc. owing to its resistance to weathering and easy workability. The polished and finished Vindhyan sandstone with attractive natural aesthetic bedding patterns i.e. current bedding, curved bedding, spots due to iron staining etc. make it a dimension stone in vogue both nationally and internationally, Canada, Middle East counties, Japan, to name a few.

Figure 1. Architectonic heritage made in Vindhyan sandstone which are also UNESCO world heritage sites (a) Paintings in Bhimbetika rock shelters in Madhya Pradesh from Mesolithic

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period (Photo: Gurmeet Kaur); (b) Bedded ferruginous Vindhyan sandstone outcrop at Bhimbetika (Photo: Gurmeet Kaur); (c) Carved sandstone pillar at Sanchi, Madhya Pradesh (Photo: Satwinder Kaur); (d) World famous Khajuraho temples in Madhya Pradesh; (e) Carved exterior wall in one of the Khajuraho temple (Photo: Satwinder Kaur).

Figure 2. Architectonic heritage made in Vindhyan sandstone (a) Gateway to Agra Fort (Photo: Manoj Pandit); (b) Tomb of Safdar Jung built in sandstone and marble, New Delhi (Photo: Uday Sharma); (c) View of Central Secretariat building, New Delhi (Photo: Anuvinder Ahuja); (d) Glimpse of Panjab University, Chandigarh, built in red sandstone (Photo: Pranshu).

Acknowledgements: Authors Gurmeet Kaur, Parminder Kaur and Sanchit Garg gratefully acknowledge UNESCO-IUGS IGCP-637 for granting partial funds to attend the Salamanca Workshop on Heritage Stones being organized by the IUGS Heritage Stones Subcommission from 2nd to 4th October, 2018. We acknowledge Satwinder Kaur, Uday Sharma and Pranshu for contributing pictures to this project.

Keywords: Vindhyan sandstone, India, World Heritage site

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LIMESTONES AND MARBLES FROM PORTUGAL: COLORS, TEXTURES AND PATTERNS

L. Lopesa*, J. Mirãob, L. Diasc

aUniversidade de Évora, Escola de Ciências e Tecnologia, Departamento de Geociências &

Instituto de Ciências da Terra. Rua Romão Ramalho, 59 Apartado 94,7000 671 Évora, Portugal; bUniversidade de Évora, Escola de Ciências e Tecnologia, Departamento de Geociências &

Centro Hércules, FCT. Rua Romão Ramalho, 59 Apartado 94,7000 671 Évora, Portugal; cUniversidade de Évora, Escola de Ciências e Tecnologia, Departamento de Geociências &

Centro Hércules, FCT. Largo Marquês de Marialva, 8. Palácio do Vimioso, 7000-089 Évora. *[email protected]

Introduction In order to be a relevant player in the global natural stone market, Europe, including Portugal, should continue to invest in technological development, as well as offering new services and specifications such as after-sales service and certification of the raw material. Several factors control the choice of one stone over another. Color, insofar as is considered in statuary or architecture, is one of the most important visible aspects of natural stone (Fig. 1). There is an almost infinite choice of Natural Stone colors, which control the macroscopic aspect of the material (Siegesmund & Török, 2011). In limestone and marble, white or beige tones are dominant, but it is possible to find carbonated rocks with rather exotic colors, such as red, pink, black or green. Despite is almost identical geochemical composition, limestones and marbles are sometimes and not always innocently, confused. Especially in the economic world, but also in scientific articles, it is common to see references to marble when reported to limestones. In fact, the meaning of "distinctive, brilliant and crystalline stone", related to marble, is more appealing than the word "limestone" (literally, "lime" or "mud" is not at all appealing). To the geologist no mistake is possible, despite, in some cases of microcrystalline limestone at macroscopic scale, presents similar characteristics of fine grain marbles. This in the case of the “Lioz” (Lopes, 2017). Nevertheless, any thin section is enough to clear this point. Therefore, in this brief work, we summarize the main colors and textures of commercial varieties of Portuguese marbles and limestones focusing on macroscopic aspects, laboratory multi-analysis approach and thin sections. Since is not possible to illustrate each one, in the poster presentation some varieties will be shown in groups of similar properties. Description of the Project Color is one of the main arguments that guides the customer's decision and the value of the material. In this way, it is essential to know how the color of each carbonated rock (limestone or marble) is naturally achieved. Considering that the predominant mineral in these carbonates is calcite, it is possible to anticipate two mechanisms: (1) modifying the color of calcite and (2) modifying the color of the rock by incorporating certain amounts of foreign minerals:

1) incorporation of foreign metals, such as iron or manganese, into the crystalline structure of carbonated minerals such as calcite or dolomite;

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2) the presence, in varying amounts, of different minerals or compounds which modify the original color, eg. green (eg. presence of chlorite, fuchsite, malachite), black (eg. presence of organic matter) or beige (eg. presence of clay minerals).

Figure 1. Some textures, colors and patterns present in Portuguese carbonated ornamental rocks. From the top and left to right: open book pattern in Estremoz marble; 1 m long mural with limestones, marbles and serpentinite; Évora’s Cathedral floor composition with limestones and marbles; rare green Estremoz marble slab; “Rosa Portugal” Estremoz marble block and two colors Ataíja limestone block.

Thus, it is possible to understand the color of limestone or marbles as a geochemical or mineralogical matter. Full understanding of the coloring mechanism is essential:

I. during the operation of a quarry, to know the color of the new blocks in advance; II. to predict the future behavior of the color of each rock after its application;

III. to plan the preventive and corrective treatment of rocks, with respect to color or other physical properties.

Considering that discoloration is a crucial aspect in the commercial value of stone, the color and discoloration of carbonated rocks, are therefore a relevant scientific problem with economic consequences. Color changes can occur through several processes, such as:

a) inorganic weathering of rocks and production of new mineralogical phases with new colors (Tiwari et al., 2005);

b) deposition of inorganic patinas, mainly in very polluted environments (Pavia & Caro, 2006; Grossi et al., 2007);

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c) biological colonization, organic weathering or discoloration by biogenic pigments in ornamental rocks;

d) human action (eg vandalism), conservation and restoration actions or cleanings with harmful consequences (Andreotti et al., 2009).

In general, inorganic or organic processes associated with biological colonization may alter the original color. Of course, the two processes often work together. Inorganic rock weathering processes are well known, but within ornamental rocks, aesthetic details, the presence of human activity and commercial surface finishing techniques (Urosevic et al., 2013) may lead to differences in the discoloration patterns of weathering. Conclusions The team of the project "ColourStone - Color of marbles and commercial limestone: causes and alterations" aims to explain, through geochemical, mineralogical and biochemical methods, the color and discoloration of the main commercially important carbonated rocks in Portugal. The chromatic processes in limestones and marbles should be fully understood. It is expected that the results of the project will influence future technological applications making it possible to certify and guarantee the color of the stones sold. This project will allow the creation of essential scientific knowledge in support of new industrial and technological projects (i.e. Portugal2020 and Alentejo2020). These will contribute to increase the competitiveness of the ornamental stone sector and the creation of certification tools that, in this way, will generate benefit for Portuguese and European Natural Stone in the international markets. Acknowledgment: This paper is a contribution to the project: COLOURSTONE: Colour of commercial marbles and limestone: causes and changings. ALT20-03-0145-FEDER-000017. Bibliography Andreotti A, Bonaduce I, Colombini MP, Modugno F, Ribechini E: A diagnosis of the yellowing of the marble high reliefs and the black decoration on the chapel of the tomb of Saint Anthony (Padua, Italy). Int J Mass Spectrom 2009, 284:123-130 Grossi, C. M., Brimblecombe, P., Esbert, R. M. and Alonso, F. J. (2007), Color changes in architectural limestones from pollution and cleaning. Color Res. Appl., 32: 320–331. Lopes, L. 2007. Lioz: The Stone that made Lisbon reborn – A Global Heritage Stone Resource Proposal. Geophysical Research Abstracts. Vol. 19, EGU2017-11228-3, 2017. EGU General Assembly 2017. © Author(s) 2017. CC Attribution 3.0 License. Pavía, S.; Caro, S. 2006. Origin of Films on Monumental Stone, Studies in Conservation, 51, (3), pp. 177-188 Siegesmund, S., Török. A. 2011. Building Stones in In Stone in Architecture: Properties, Durability . 4th ed. ed. S. Siegesmund and R. Snethlage. , Springer-verlag, pp 11-96 Tiwari, L. B.; Jahagirdar, C. J.; Deshpande, V. D.; Srinivasan, R.; Parthasarathy, G. 2005. Weathering impact on the colour of building stones of the `Gateway of India' monument. Environmental Geology, 48 (6), pp.788-794 Urosevic, M., Sebastián, E., Cardell, C. 2013. An experimental study on the influence of surface finishing on the weathering of a building low-porous limestone in coastal environments, Engineering Geology, 154, pp. 131-141 Keywords: limestone, marbles, Portugal, dimension stone, colors.

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THE SANDSTONE “PIEDRA BOGOTANA” AS HERITAGE STONE IN COLOMBIA

J. E. Becerra Becerraa*, D. Benaventeb, J. C. Cañaverasb

aDepartment of Civil Engineering. Santo Tomás University: Avenida Universitaria. Calle 48 # 1-235 Este - Tunja (Boyacá) – Colombia. Postal Code150001.

bDepartment of Earth and Environmental Sciences. University of Alicante; Carretera San Vicente del Raspeig s/n 03690. San Vicente del Raspeig (Alicante) –.Spain Postal Code 03080.

*[email protected].

Introduction Sandstones of the Upper Cretaceous age have been widely used as stone material in heritage building since pre-colombian time until today in cities like Bogotá, Tunja, Barichara, Monguí, Puente Nacional and other historical and moderns sites in the Eastern region from Colombia. The sandstone called “Piedra Bogotana” or “Piedra Muñeca” has relevant importance in the history and recent construction in Bogotá, capital of Colombia. There are some buildings, as the National Capitol, Primatial Cathedral, and others, that shows the use of this material as pavements, external facades, structural elements, and ornaments. The research and the knowledge about the properties of this stone is important for conservation processes and the valorization as heritage stone in Colombia. “Piedra Bogotana” as heritage Stone The objective of this research is to determine the most important characteristics of the sandstone “Piedra Bogotana” as heritage stone and their role in the mechanical behavior and the deterioration processes, which can be observed in some historical and contemporaneous buildings in Bogotá (Figure 1).

Figure 1. Use of sandstone “Piedra Bogotana” in Primatial Cathedral and Municipality building used as pavements and external facades. Bogotá (Colombia). Petrographic analysis, physical properties (i.e. bulk density, bulk porosity and water open absorption), mechanical tests as compressive strength and hydric properties as capillary absorption, were carried out according to international norms.

A B

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Several quarries where sandstone “Piedra Bogotana” has been extracted can be identified, but currently just a few are active. All quarries located close to Bogotá are closed due the Colombian environmental regulation. The extraction of stone materials near the city of Bogotá is not allowed to protect the forest and water resources. “Piedra Bogotana” is a sandstone from Arenisca de Labor Formation of Maastrichtian age. It is a fine-grained sandstone (0,05-0,15mm) which consist primarily of quartz with small amount of k-feldspar and lithic fragments. It also presents micas (muscovite), as well as iron oxides that cause the frequent change of color of the rock from yellowish to pink. Other minerals, eg zircon are also included. The cement consist mainly of iron oxides (Figure 2).

Figure 2. Microphotographs showing some details of the studied sandstones. Moderately-sorted quartz grains in a clay matrix and muscovite as accessory. (A) Plane-polarized light. (B) cross-polarized light. The sandstone porosity is high, 23% on average, and ranges from 10 to 25%. There are little differences in pore structure in the two varieties. The yellow variety shows more connected porosity and highly capillary absorption than pink variety, and more susceptibility to deterioration processes due to the urban pollution. The values of bulk density, open porosity and water apparent absorption are higher in yellowish than pink variety. There are some differences in mechanical behavior in the stone related with the color; compression strength is higher in pink variety (67,08 Mpa) than yellowish (16,28MPa). Conclusions The study of sandstones as heritage stone is needed due their use as structural and ornamental elements in historical and modern builds in Bogotá and other Colombian cities. The knowledge of characteristics as mechanical behavior, mineralogy and deterioration patterns of “Piedra Bogotana”, one of the most important stone in heritage buildings, gives fundamental information to understand the problems, to identify conservation needs and to define conservation actions. The sandstone "Piedra Bogotana" could become a candidate for nomination as "Global heritage stone resource" from Colombia. Keywords: sandstone, heritage, deterioration, Colombia.

A B

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LOCATION OF HISTORICAL QUARRIES AND ULTRASONIC CHARACTERIZATION OF HISTORIC SETTS USED AS PAVEMENTS OF MADRID

(SPAIN)

D. M. Freire-Listaa*, A. Zaloolib

aInstituto de Geociencias IGEO (CSIC, UCM) Spanish Research Council CSIC – Complutense University of Madrid UCM. Madrid, Spain. Calle Severo Ochoa 7, entre pabellones 7, 8 28040.

Madrid (Spain) bDepartment of Geology, Faculty of Science, Tarbiat Modares, University, Tehran 14155�111, Iran * [email protected]

Introduction Identity of historic streets is defined by the original setts that form part of their pavements. These stone setts are historical relics at risk of disappearing or being buried due to the use of other new materials (Fig. 1). The aims of this study are to determine the historical quarries of origin of the stones used as traditional setts in Madrid (Spain), to characterize the stone setts by their ultrasonic pulse velocity, and to measure their size. This study will contribute with valuable knowledge to ensure the preservation of historical streets of Madrid (Fig. 2).

Figure 1. a Historical setts of Carrera de San Jerónimo, Madrid (1900). b. Elimination of historic setts in Lavapiés neighborhood, Madrid (1985)

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Figure 2. a Pretil de los Consejos Street view, Madrid (2018). b and c. Setts detail. Pretil de los

Consejos Street, Madrid (2018) Materials and methods An intensive search of historical documentation was done. Historical documents have provided data about stone provenance and historical photographs have provided information about stone setts used in the last century. The eleven stones selected have been traditionally used as setts in Madrid and its surroundings. The samples were selected from outcrops at historical quarries where the stone was fresh and fracture-free. Seven cubic (5 × 5 × 5±0.5 cm) specimens of each of the eleven stone types were extracted at a low cutting speed (120 rpm) and low strain. Ultrasonic pulse velocity (Vp) measurements were taken with CNS Electronics PUNDIT equipment (precision: ±0.1 µs) according to Spanish and European standard UNE-EN, 14579, 2005. The even and round (11.82 mm in diameter) 1 MHz transducers were affixed to the stone surface with Henkel Sichozell Kleister (a carboxymethyl cellulose) paste and water to enhance the transducer-stone contact and bond. Vp was measured on each sample in the three orthogonal directions, using the mean of four consecutive measurements on each side of the cube as the accepted value. Results and Discussion Table 1 shows the origin of the main stones used as setts in Madrid and the average dimensions of the traditional setts. The ultrasound propagation velocity (Vp) is also indicated for each type of stone. The lithologies identified as building material of Madrid historical setts are: aplite from Gerena (Seville, Spain); basalt from Villamayor de Calatrava (Ciudad Real, Spain); leucogranite from La Cabrera; monzogranite from Alpedrete, Cerdeda, El Boalo, Zarzalejo, Mataelpino and

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Moralzarzal; and porphyry from Colmenar Viejo (Madrid, Spain). The Basalt of Villamayor de Calatrava has the highest Vp, while the monzogranite of Zarzalejo has the lowest Vp.

Table 1: Main historical quarries, sizes and Vp of Madrid traditional setts. Conclusions Madrid preserves few streets with original stone setts. Knowledge of stones and their historic quarries of origin are necessary for conservation interventions, especially for reintegration of damaged setts. Each type of stone that forms the setts has a different Vp response. Petrographic properties of traditional pavements must be maintained in conservation and restoration projects. New materials deface historical city centers and towns and strip them of their identity. The different actors involved in urban development, and especially in built heritage conservation, must know the stones traditionally used in paving, in order to value the legacy that the city has inherited and, in turn, to be a bet for the future. Keywords: paving stone, cobblestone, heritage, urbanism.

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