dimension stones of the historical city wall of cluj-napoca, romania - construction, weathering,...

Dr. Paul Calin RACATAIANU

Bausteine der historichen Stadtmauervon Cluj-Napoca, Rumänien.

Konstruktion, Verwitterung, Schäden.

Dimension stones of the Historical City Wall of Cluj-

Napoca, Romania

Construction, Weathering, Damages.

• History

• Geology

• Weather, Pollution

• Wall´s characteristics, mapping, analyses, results

• Conclusions

• Acknowledgments

׀ Acknowledgments ׀ Conclusions ׀ Wall’s characteristics ׀ Weather&Pollution ׀ Geology ׀ History ׀

• The Historical City Wall – most important and distinctive symbol in Cluj-Napoca history

• The construction – a long process starting at the beginning of XVth century -> end of XVIth century

• Two stages of development of Cluj-Napoca prior to the medieval fortress• The Roman colonization 101-271 AD -> Napuca• Second setlement IXth -Xth century -> Castrum Clus

• After Tartars invasion during XIIIth Century -> colonization during King Stephan V of Hungary’s reign

• Cluj became a free imperial city in 1405 -> permision to build its own defence walls, bastions and fortified towers

• New fortress area’s – 45 ha (fortifications and town walls built from stones blocks) with loopholes

• Acces to the city – through barbicans

• Walls provided with 20 towers and numerous gates well-mantained and defended by the Craftsmen’s Guilds

History

• several factors affected the wall integrity (e.g.two catastrophic fires)

• town plannings contributed to the demolish of large parts of the wall (XVIIIth century)

12

34

• 4 parts of the wall nowadays

• ruinous condition generated by the innapropiate rock types used leaded alto to demolitions

• the city used to pay the locals to quarry the rocks and to transport them into the city -> hint for the rock source



• more than 90% of the analized remains of the wall were constructed with limestone;

• the closest accessible quarry source is the Baci Quarry, 7 km NW from Cluj-Napoca;

• EoceneEocene, Miocene and Quaternary deposits are present in Cheile Baciului (Baci);

• The limestones of this sequence were deposited on a shallow tropical carbonate platform in the Transilvanian Basin during the late Eocene – Early Oligocene;

• Several terestrial input episodes from the surrounding areas -> changing of the composition: quartz, feldspar grains and clay were admixed with carbonate content

Geology

• more than 90% of the analized remains of the wall were constructed with limestone;

• the closest accessible quarry source is the Baci Quarry, 7 km NW from Cluj-Napoca;

• EoceneEocene, Miocene and Quaternary deposits are present in Cheile Baciului (Baci);

• The limestones of this sequence were deposited on a shallow tropical carbonate platform in the Transilvanian Basin during the late Eocene – Early Oligocene;

• Several terestrial input episodes from the surrounding areas -> changing of the composition: quartz, feldspar grains and clay were admixed with carbonate content



• mixed composition → complex mineralogy in the Cluj limestone:

• calcite cristals, quartz, limonite, detrital muscovite, pyrite and limonite affect the quality

• aglomeration of fossils mixed with the detrital input during sedimentation - > decrease of limestone quality

• Distributed in different layers within the Baci quarry, the blocks vary in quality

• Quaried over a long period of time -> homogenity in the wall is low


• Baci Quarry (7km, NW of Cluj-Napoca): A - overview - oolitic bioclastic limestone alternating with greyish claystones B, C, D - bioclastic oolitic limestone from the lower part

• the identified microfacies types:• bioclastic oolitic grainstone-packestone (E, F)

with miliolids, gastropods, lamellibranchiates and echinoid fragments• bioclastic wackestone (C, D) with Characeans, ostracodes and plant fragments (carboniferous)• extraclastic bioclastic packestone (E) with

benthonic foraminifera (milliolids), plates and spines of echinoids, fragments of molluscs and red algae

• bioclastic wackestone-packestone (F) with milliolids• extraclastic bioclastic grainstone-packestone with benthonic foraminifera, red algae and mollusc fragments and plates and spines of echinoids• bioclastic wackestone-packestone with miliolids an echinoids fragments


A - boundary between the lacustrine and marine deposits B - green lacustrine siltic claystone

• the identified microfacies types:• bioclastic oolitic grainstone-packestone with miliolids, gastropods, lamellibranchiates and echinoid fragments• bioclastic wackestone (C, D) with Characeans, ostracodes and plant fragments (carboniferous)• extraclastic bioclastic packestone (E) with


• bioclastic wackestone-packestone (F) with milliolids• extraclastic bioclastic grainstone-packestone with benthonic foraminifera, red algae and mollusc fragments and plates and spines of echinoids• bioclastic wackestone-packestone with miliolids an echinoids fragments


A – overview – alternation of bioclastic limestone, marls, and greyish bioclastic claystones B - green lacustrine siltic claystone

• the identified microfacies types:• bioclastic oolitic grainstone-packestone with miliolids, gastropods, lamellibranchiates and echinoid fragments• bioclastic wackestone with

Characeans, ostracodes and plant fragments (carboniferous)• extraclastic bioclastic packestone (E) with


• bioclastic wackestone-packestone with milliolids

• extraclastic bioclastic grainstone-packestone (B, C)

with benthonic foraminifera, red algae and mollusc fragments and plates and spines of echinoids• bioclastic wackestone-packestone (D, E) with miliolids an echinoids fragments


• Romania - a transitional temperate continental climate with four distinct seasons•to November). • Romania – six micro-climate regions

Weather&Pollution

• Particularities of the local climate in the Cluj area:

− hilly-plateau micro-climate− average annual temperature: 8° C

(min. 6° C);− average summer temperature: 20° C

(min. 18° C);− average winter temperature: -4° C

(max. -5° C);− rainfall: 600-700 mm/year;− semi-arid, dry sub-humid and humid

zones (aridity index)

Average annual temperature from 1961-2000


• Hours of sunshine - over 2200 hours/year • The dominant wind - “Nemer” (average annual wind speed 1-2 m/s)• Strong winds from the east creeps – strong blizzards in the winter (20-25 m/s)


• strong winds from W to E and SW to NE and the wind corridors → direct impact on the wall → rapid drying of the wall, constant supplying with dust, sand, metal and coal particles → crust formation

N

S

W E


Air pollution → contribute to the weathering → crusts formation (reason: concentrations of SO2, NOX, particles in suspension)

The decay processes – associated with burning of fossil fuels + conversion of atmospheric SO2 to sulphuric acid in rainfalls

- sulphuric acids attack and dissolve the CaCO3 → CaSO4·2H2O (gypsum) → crust formation and accelerated erosion

- black crusts developed by gypsum crust formation on surfaced sheltered from water and attacked by SO2 polluted atmosphere

- black crusts consist of carbonaceous particles from petroleum derivate, clay minerals (from soil dust and heavy metals)


Sulphur dioxide (SO2)

-main sources: industry, burning of fossil fuel and car traffic

-In combination with the dust particles from the industrial area → coloured crusts

29626,75

178496,83

35645,25

74025,02

240821,53

8725,32 23353,17

22155,18 23644,72

2000 2001 2002 2003 2004 2005 2006 2007 2008

Annual SO2 emissions (tons/year)

87,79%

0,39%

2,94% 5,08% 0,83% 2,97%

Bihor County

Bistrita NasaudCountyCluj County

Maramures County

Annual SO2 emissions in NW Romania from 2000 to 2008


Concentration of SO2 measured in four locations in Cluj-Napoca (2007)

Industrial13 μg/m3

Traffic8 μg/m3

Urban11.5 μg/m3

Urban13.5 μg/m3

Limit20 μg/m3

Wind Direction


Particles in suspension (dust, ashes)

-a complex admixture of very fine particles and liquid drops, extremely diverse, containing carbon particles (ashes), heavy metals, iron oxides, sulphates and other toxic noxious pollutants

-various sources: the industrial processes (metallurgy, ferrous metallurgy), power plants using solid fuels, cement factories, road transportation and dung heaps

-In Cluj County the average annual quantity of the particles in suspension is 600.732 tons/year (50% in 2008 less than in 2007)

SO2 + NOX + Particles in suspension (dust, ashes) + water -> crusts


Walls’ characteristicsLocation 1

Location 3

Location 2

Location 4


bioclastic oolitic limestone bioclastic limestone

bioclastic limestone with clay intercalations calcareous sandstones

ROCK

TYPES


MORTAR

TYPES

lime mortar

cement mortar

GD→

GD→

CSC→

CSC→


BC→

AV→

←SS

←LCCS

LCS→

SA→

SA→

←WOS

←SS

GD→

MS→

MS→

MF→MF→

S→

DAMAGES


CDC→

CDC→

CDC→

←RN

←RN

F→

WO→

CCS→

CSC→

CSC→

F→

←WO

CCS→

RN→

BC→

GD→

MF→

DC→

←DC

RN→

DS→

AV→

AV→

RN→

AV→

DAMAGES


MS→

CCS→

MS→

MS→

MS→

SA→

CS→

←WO

BW→

SA→

RN→

←S

←DC

S→

DS→←BW

WOS→

WOS→

WOS→

←RN

DAMAGES

SS→

C→

BC→

S→

CSC→

C→

←WOS

←WOS

←WOS

F→

F→

F→


The monuments non-destructive mapping method used for: blocks mapping, damage mapping, rock type mapping, sound velocity test mapping, moisture mapping.

Results of the mapping revealed weathering formes classified by Fitzner -> indexed by a new investigation model and database of the data colected in situ (New Damage Mapping System)


L1

L2

L3

L4


L1

L2

L3

L4

0,010,020,030,040,050,060,070,080,090,0

100,0

Location 1 Location 2 Location 3 Location 4 Average

81,5 96,9

81,1 85,9 86,4


L1

L2

L3

L4


Eocene limestones from Baci quarry were used for the construction of the wall.

The identified microfacies in the limestone samples correspond with the microfacies identified in the quarry samples.

• the identified microfacies types:

• oolitic packstone-grainstone

• gastropode-rich, ooid-bearing bioclastic packstone

• quartz-rich oolitic grainstone

• fossiliferous mudstone to foraminiferal wackestone

• ooid-bearing grainstone-packstone-wackestone alternation

• gastropode-rich oolitic packstone-grainstone

• foraminiferal-peloid packstone


Eocene limestones from Baci quarry were used for the construction of the wall.

The identified microfacies in the limestone samples correspond with the microfacies identified in the quarry samples.

• the identified microfacies types:

• oolitic grainstone

• ooid-bearing bioclastic foraminiferal grainstone


WEATHERING


L

L

L

L

G

G G

G

WEATHERING


?


NEW DAMAGE MAPPING SYSTEM


41,23%

26,62%

30,19%

L1 - Hammer clash test (Sound velocity test)

WITHOUTDAMAGES

MODERATEDAMAGES

SEVEREDAMAGES

0,0 20,0 40,0 60,0 80,0 100,0 120,0

17.1017.2

15.1615.8

14.2614.17

14.813.28

13.812.2612.1811.2411.1610.2410.16

9.209.128.17

8.87.207.12

7.46.4

5.315.235.15

5.74.284.194.11

4.33.21

3.93.1

2.232.15

2.51.12

1.4

L1 - Relative humidity

0 1 2 3 4 5 6 7 8 9 10

Bu

ild

ing

sto

ne

s (b

ott

om

to

to

p)

Number of the weathering processes/building stone


Conclusions

Physical damage 1601; 1697 (catastrophic fires). Ruinous condition due to inappropriate rock types used and intensive weathering.

1116 building stones were studied:86.92% limestones, 9.05% sandstones, 0.81% mortar fillings, 3.23% bricks and other materials.

Eocene limestones from Baci quarry were used.Fifteen facies types occur in the wall corresponding to microfacies types from Baci quarry.

Temperate continental climate; extreme temperature fluctuations (long winter, freeze-thaw cycles), winds from W and SW; wind corridors.

Annual rainfall (high moisture throughout the year). Lower part of the walls saturated with capillary water, middle part “dried due to wind and insolation; upper part infiltrated by rainwater.

Air pollution contributes to the weathering processes.

57.71% of the blocks need restoration15.77% need total replacement26.52% need partial restoration


28 weathering processes were identified (e.g. discoloration/deposits(formation of crusts, detachments, loss of stone material, fissures/Deformations. Most of the stones reveal several weathering process per building stone.

Dissolution results in high microporosity. Vugs and fractures were formed. Gypsum crystals grow in fractures oriented parallel to the surface.

The inappropriate usage of cement mortar contributed to advanced deterioration.

Proposals for restoration:

(A) Cleaning and stabilisation of the stone surface, of lose and broken stones, and of cracks, removing the vegetation

(B) Replacing completely damaged stones, reconstruction of missing parts, replacing missing or previously removed mortars by appropriate (historical) mortars.


• Prof. Dr. Roman Koch, FAU Erlangen-Nuernberg, Germany;

• Prof. Dr. Reinhold Roßner and Prof. Dr. Joachim Rohn , FAU Erlangen-Nuernberg, Germany;

• Colleagues from PaläoUmwelt and from Angewandte Geowissenschaften, Erlangen, Germany;

• Colleauges and friends from the Biology-Geology Faculty, Babes-Bolyai University in Cluj-Napoca, Romania;

• Mr. Emil Boc, the nowadays mayor of Cluj-Napoca, Romania, former prime-minister of Romania.

Acknowledgments

dimension stones of the historical city wall of cluj-napoca, romania - construction, weathering,...

Education

town walls

clujnapoca eocene

defence walls

barbicans walls

nw of clujnapoca

historical city wall

quaternary eocene deposits

wall integrity