GEOLOGICAL MAPPING REPORT

JIWO BARAT-TIMUR MOUNTAIN

BAYAT, KLATEN

ARRANGED BY :

1. ARIF DWI KURNIAWAN (XII GPA/11)2. ASTYADY BAHTERA (XII GPA/13)3. EDWIN PRASETYA (XII GPA/27)4. GALIH WIDHI PRIAWAN (XII GPB/02)5. ISMATUN CHASANAH (XII GPB/09)6. SEPTIAN ADI NUGRAHA (XII GPB/26)

COMPETENCE PROGRAM OF MINING GEOLOGY

SMK N 2 DEPOK

( STM PEMBANGUNAN YOGYAKARTA )

2012

ABSTRACT

The administrative area located in the East Jiwo Hills Regional, District Bayat, Klaten. Is

geographically located at coordinates S 7 ° 44'40 "- 7 ° 47'15" and E 110 ° 36'30 "- 110 ° 39'30"

sheet included in the map Rowo - Djombor 1:12500 scale.

Jiwo regions West and East Jiwo Dengkeng separated by the river, which cuts the

antecedent of a row of hills. Dengkeng river itself has a complex flow around Jiwo West, began

to flow to the south east, veered towards the east and then north, then cut the flow towards the

hills to the northeast. Dengkeng river is the main dryer from the lowlands around the hills Jiwo.

Lowlands was originally a vast swamp, due to water flowing from Mount Merapi held by the

Southern Mountains.

The oldest rocks exposed Jiwo Hills area is a complex of metamorphic rocks of Pre-

Tertiary age alleged. This is the basement complex rocks of the Paleogene sedimentary basins,

and is one of the oldest rocks in Java, similar to that found in the area Karangsambung,

Kebumen, Central Java and West Java Ciletuh. Paleogene sediment encountered a sandstone

with limestone-rich insertions large foraminifera. Rocks are intruded by igneous bodies

consisting primarily of mikrodiorit. This alleged breach occurred in late Paleogene.

Is not aligned on top of igneous and sedimentary rocks are included Paleogene carbonate rocks

was encountered Neogendlam form two distinct facies, the marine facies and shallow marine

facies.

Metamorphic rocks form the hills are scattered with a strong and terbiku relief of

moderate to strong, with a tapered peaks, some of which form a cone. In the area of West Jiwo

deployment Jabalkat rock covers hills in the south to the northern Sari. On the southwestern

slope Jabalkat, Pagerjurang area, found between the serpentinite and schist filit, which shows

garnet mineralization. Near the top of the claw, Kebo, and metamorphic rocks pegat is intruded

by diorite body, mikrodiorit and gabbro. Gabbro intrusions are also present south slope of G.

Jabalkat. While on the river between the peak Kebo G.Kebo with G.Cakaran and G.Merak,

found a breakthrough in the form of rock diorite and basalt. Absolute dating of igneous rocks in

this place shows the age of 36 Mya., The Oligocene (SoeriaAtmaja, 1991). In the area of East

Jiwo metamorphic rocks of the area G.Konang found at the western end, forming an elongated

hill towards the east.

Age of metamorphic rocks cannot be known precisely. Bothe (1929) states that in the

pesantren in the East Jiwo found conglomerate containing fragments of marble, and marble are

found in large fragments of foraminifera Orbitolina. On the basis of this data then he stated that

the metamorphic rock derived from limestone that formed in the Cretaceous. However, because

these data are the only data that is not accompanied by a convincing illustration, the conclusion

from the time of the chalk cannot be held. To be safe, because the metamorphic rocks are located

not in harmony under the Tertiary rocks, it is generally said that the metamorphic rocks are from

Pre-Tertiary age.

CHAPTERI

INTRODUCTION

I.I.Background

In the present we always hear a well known word “Past is The Key to the Present” . it means hat

everything that happens nowadays is the done of the past process. Unexcepted about geology,

geology is a science that learn about the process of forming the earth. So we as a student that in

this competence, we have to learn.

Because that, we do the the mapping of certain to know what process that happen. And as a final

exam. We have an assignment for mapping Perbukitan Jiwo Barat-Timur. To observe the

geology process,what geology structur that happened and soon.

After we collect the data of the field. We produce it into a map.

I.II. PURPOSE AND OBJECTIVES

Practice making this map the freshman intends to make the freshman special regional maps.

With the addition of rock types as well as giving details of the distribution, rock layers, the type

of structure, and analyze the relationship of the overall data we get.

In addition to the above bleak intends this practice also aims to:

1. Studied the face of the earth that is in the Bayat

2. Add knowledge about the geology surrounding area

3. Familiarize calculation using a compass

4. Create a contour map of the area Bayat

5. Familiarize the use of GPS in accordance with the requirements

6. Get used to working in the field

7. Know the location of the position of rocks and spread

8. Search for geological structures in the area Bayat

9. Apply all the knowledge learned in school

I.III. Location and Regional Acomplish

Location in the hills of West Jiwo and precisely in the Eastern District JiwoBayat, Klaten

regency, Central Java. On the first day we did Recognize. The second and third day of practice

we did in the East Hills Jiwo. Precisely in the area including and surrounding Watupraupendul

foothills north and south Semangu foothills.while the third and final day we were in the hills of

West Jiwo.

The trip from Yogyakarta to the location of base camp about 1 hour with an average speed of a

motorbike with 60km/jam traffic conditions not too crowded.

I.IV.Equipment

During practice we use the following equipment:

1. Stationery

Stationery to record data obtained from the field during the field practicum in Bayat.

2. Topographic Map

Topographic map used is the Bayat area with a scale of 1: 12,500. This map is always

taken to a field that will be used to mengeplotkan observation locations that have been

marked on the GPS and data entry position of rocks that have been measured.

3. Hardboard

Helps to measure the position of rocks and structures as well as a form of muscular pad in

recording data.

4. Field book

Used as a recording of the data obtained in field

5. GPS

Used to determine the coordinates of the location of the observations and find its height.

In the lab this time each group took GPS 1 piece

6. Compass Geology

Geological compass is used to measure the position of the rock, slope, and also structures

such as muscular and others as well as assist in mapping the so-called compass step.

Geological compass we carry are bruntton type as much as 2 pieces

7. Geological hammer

Geological hammer is used to take a sample from an outcrop of rock encountered in the

field. We took samples of hand specimen size (size of a fist). Geological hammer itself

consists of two types, namely:

• Geology Rocks Frozen Hammer, one of the pointy-shaped part which serves for

sampling by splitting and for the hard rock which is found in many igneous rocks that

have interlocking with each other minerals.

• Sedimentary rocks Geological Hammer, one of the flat-shaped parts that function for

sampling by prying.

8. Tableware (including default provisions)

Used to bring food for lunch. Because the lab that can be up to the afternoon so they can

save time to eat without having to find a place to eat.

9. Bag

To accommodate other equipment that would fit into the bag to be more practical in

carrying.

10. Camera

To document the rock outcrop and geological circumstances at each location on-site

observation and can be used as a substitute for field sketching.

11. sample bags

Used to place and separate samples taken from each site observation which will be

labeled.

12. plane table

Plane Table is one of the measurements using a simple tool for mapping. Which was the

purpose of these measurements with the plane table is a topographic map can be directly

drawn on a flat table that is placed above the telescope so that the stative along with a

map can be directly done in the field. This tool uses signs as a tool for target shooting of a

point to be mapped.

13. total Station

Is a mapping tool that is more sophisticated than the plane table because it has a more

distant range and there is a digital menu display. Total station is using the tools in the

form of prisms which later became the target of the shooting of a point to be mapped.

14. HCl

HCl is used to determine whether it's a kind of carbonate rock samples or not. Because

the HCl will react to that type of carbonate rocks.

I.V. I.V BASIC THEORY

A. DEFINITION OF GEOLOGICAL MAP

As we all know that our understanding is the image of the earth on a flat surface

with a certain scale through a projection system. Then the general understanding of

geology is the study of planet Earth, including the composition, of constitution, and

history.

Geological Map of the definition according to (SNI-4691, 1998) is a picture or shape by

means of the expression data and geological information of a region / area / region with a

level of quality based on scale

Geological maps can be interpreted also as an image which is a form of data and

geological information of an area or region with a level of quality depends on the scale of

the map being used. Geological map illustrates the spread of information, the type and

nature of the rocks, age, stratigraphy, structure, tectonics, physiography and potential

mineral resources and energy are also presented in the form of an image with colors,

symbols or any combination of the three.

Geological map is an illustration of a large volume of geological information. By

using geological maps, geologists can show the distribution of rocks on the earth's

surface and geological structure of rocks that have been deforming. Geological map

showing the occurrence, nature, extent and stratigraphic age of rock layers in an area.

Geological maps provide information on the superficial layers of the earth's crust. Choice

in making a geological map scale depending on the content and purpose of geological

maps.

Essential condition for building a detailed geological map is a proper field survey,

based on measurements and observations of many. Field geologist determines the type of

stone according to various criteria and measures orientation. All data is translated into the

map and in the field notebook. In addition to natural or man-made picture, data from test

holes or drill holes is important that taken into consideration.

At the end of the field survey, geologists made the original manuscript with a scale of 1:

25,000 and make some parts of the geology in the area to be studied. And to write

explanatory notes which generally contain much information.

Geological maps can be distinguished on the systematic geological maps and geological

thematic maps. Systematic geological map is a map that presents data on the geological

base map topography. Topographic map itself is a map of the height of the point or

region expressed as a number of heights or height contours are measured against the

average sea level. While the thematic geological maps are maps that provide geological

information and / or mineral resource potential and / or energy for a particular purpose.

Geological mapping is a job or geological data collection activities, both land and sea,

with various methods. The symbol itself is a sign that is used to describe something on

the geological map, in the form of short letters, colors, symbols and patterns, or a

combination of all three.

letter abbreviation

Kronostratigrafi geological units on the map indicated by letter abbreviations. As

document / reference unit kronostratigrafi is a table created by Elsevier (1989)

1. The first letter (capital letter) stating the time, for example P for female, TR for

Triassic, T for the Tertiary.

2. The second letter (lower case) said the series, for example, Tm mean when the

Miocene in the Tertiary era.

3. The third letter (small letters) stating the name of formations or lithological units,

such as Tmc means Cipluk Miocene formations.

4. These four letters (lower case) stating the type lithology or maps of the lower unit

(members), for example Tmcl means a member of the limestone formations Cipluk

Miocene.

5. The fifth letter is used only to rocks that have a range of long life, for example, means

the member CawangTpokcKikim Formation Paleocene-Oligocene age.

6. Letter pT (p small before large T) is used for short age before the Tertiary rocks of

unknown age for sure.

7. For rocks that have a range of long life, short sequence based on the dominance of old

age rocks, such as QT for Tertiary to Quaternary age rocks are dominated by old rock

Quarter; JK for Jurassic to Cretaceous age rocks are predominantly Jurassic age

rocks.

8. Igneous and metamorphic arrangement that is not detailed enough and he was

declared with one or two letters, for example, a for andesite, b for the basal, gd to

granodiorite, or um to ultramafic ophiolite and s for the schist

9. Igneous and metamorphic age is known to use the font symbol period, eg Kg mean

age of the Cretaceous granite.

On a small scale geological maps, the set of rocks is quite otherwise with the

letter behind the symbol of the era, era or sub-period, for example Pzm mean age of

Paleozoic metamorphic rocks, Ks mean age of the Cretaceous sediments, Tmsv

means klastika Miocene volcano, TPV mean age of volcanic rocks in Paleogene ,

military means was groundbreaking rock Neogen. Bancuh unit represented by the

notation .

Tata Colors

Color is used to distinguish the geological map units, based on selected rock types, ages

of units and unit geokronologi.

1. The basic colors used are yellow, magenta (red) and cyan (blue) and a combination

thereof. Each color is represented by code 0, 1, 3, 5, 7 and x, ie the degree of force the

color code.

2. The selected color to distinguish sedimentary rock units and fully adheres to the

surface sediment color system based on the type and age. To distinguish the entire unit

can be used several shades of.

3. Metamorphic rocks are distinguished by (1) the degree and facies, and (2) relative age

of the pre-metamorphic rocks and lithology. Full color with metamorphic rocks of

sedimentary rocks or using a special color of the rocks.

4. Tectonic unit represented by a special pattern.

5. And layered volcanic rocks and known age, to follow the color for sedimentary rocks.

6. Symbols and notation (hue) are indicated on a geological map must be contained in the

legend

Symbols and Geological Features

Symbols and notation (hue) are indicated on a geological map must be contained in the

legend and vice versa.

Types of Geological Maps

a) "surface geologic maps," or "map detail" (surface geological map) provides a variety of

geological formations which are located directly below the surface. But generally the

base of weathering is not included (map enclosed). The scale is 1: 50,000 or greater.

These maps are useful in determining the location of construction materials (sand and

gravel), drainage, water search, making airfields and roads, and so forth. In connection

with the scales used for maps, which are not often recommended tothe drilling in, dig test

wells (test pits), and so to control or determination of the critical spot.

b) Map of whistleblower or map expression (outcrop map). Generally large scale. Which

included only where the discovery of solid rock, which can provide a number of

statements and so on along with drilling and rock properties and structural conditions.

These maps are used to determine where such material for broken stone can be found

directly below the surface

c) "geological overview maps". Generally, medium or small scale, 1: 100,000 or smaller.

These maps not only provide direct observation of the formations that have been raised,

but there are times when extrapolated over a few areas covered by a layer formation such

as the Holocene.

d) "structure maps", medium to large scale. This map is a map with lines constructed on the

surface of the depth of a particular layer, which is in the ground-down.

e) "isopach maps", medium-to large-scale, in which the lines connecting points of equal

thickness and the formation or layer (structural configuration so we do not find in it).

f) The maps are created based on aerial photographs, called "photo geology map". In

general, vertical aerial photographs taken down. Cutoff-negative optic axis in the camera

(ie the earth's surface in a real situation) is called the "main point", ie the central

projection. Through the photos observation, there is the possibility of stereoscopic study;

include parallax, measuring the difference of the elevation, making the contours. Aerial

photographs (stereoscopic) can provide an excellent topographical picture, suitable for

the planning of roads, dams, etc., recognize the landslide areas, river terrace, the old river

channel edge or in a swamp area, and so forth. In areas where the geology is not much

heard, aerial photography is also used for geological orientation.

g) "hydrogeological maps". Most western countries are busy preparing a number of

questions concerning the state of soil water. A map of small-scale international overview

on Europe by the UNESCO scale 1: 1.500.000 only differentiate areas containing ground-

water in the porous rock of primary, secondary porous rocks (karst areas), and where

there are no ground-water in plateau. However this map doesn`t attract an engineer. An

engineer must be oriented on excess water charges or the presence of water that can be

used and so on, depending on the nature of the project.

B. IGNEOUS ROCK

Semuabatuanpadamulanyadari magma Magmakeluar di

permukaanbumiantaralainmelaluipuncakgunungberapi. Gunungberapiada

di daratanada pula yang di lautan. Magma yang

sudahmencapaipermukaanbumiakanmembeku. Magma yang

membekukemudianmenjadibatuanbeku.Batuanbekumukabumiselamaberi

bu-ributahunlamanyadapathancurteruraiselamaterkenapanas, hujan,

sertaaktifitastumbuhandanhewan.

Selanjutnyahancuranbatuantersebuttersangkutoleh air,

anginatauhewanketempat lain untukdiendapkan. Hancuranbatuan yang

diendapkandisebutbatuanendapanataubatuansedimen.Baikbatuansedimen

ataubekudapatberubahbentukdalamwaktu yang sangat lama

karenaadanyaperubahantemperaturdantekanan.Batuan yang

berubahbentukdisebutbatuanmalihanataubatuanmetamorf.

I. IGNEOUS ROCK

Igneous rock is rock that occurs from the freezing of liquid silicate solution and that we are

familiar with the incandescent magma. The appearance of this rock from its color it can be had

kind of - kind can be gray, white, black, reddish, and others. If you are still fresh or fresh, frozen

rocks are generally hard-mineral and mineral seem mutually interlocking (interlocked). Where

has weathered the field will look to reddish brown and easily crushed.

Igneous rocks can be divided into acid igneous, intermediate igneous rocks, alkaline igneous

rocks and ultra basic igneous rocks. If the students remember the Bowen reaction series in

Mineralogy learning that has previously been studied, then if we draw a horizontal line between

the mineral hornblende with andesin - oligoklas it is borderline intermediate rocks. In other

words, for example Andesite rock medium is generally abundant hornblende and plagioclase

minerals are white to gray's. And ultra-alkaline igneous rock base will generally contain many

piroksin minerals, olivine and plagioclase is gray to dark gray which is a mineral anortit,

bitownit or labradorit, and ultra basic igneous base rarely abundant quartz. Instead of acid

igneous rocks will appear bright because, in general contains many minerals - minerals such as

quartz and bright acid plagioclase (eg, mineral albit) and orthoklas pink / pink.

Keep in mind that the descriptions of the mineral composition of rocks to fill in so the

students cannot write the name of plagioclase by type such as Anortit, Bitownit, Labradorit,

Andesin, OligoklasorAlbit. Because of writing it by his pricing An that can only be observed

with a polarizing microscope. Given the students' descriptions of just using the naked eye and

only then assisted Loupe for descriptions of the types of plagioclase simply written:

Sodic plagioclase(acid) when the plagioclase bright colored/ white and calcic plagioclase

written(base) when the plagioclase gray-dark gray colored. Igneous rocksthat existin this

worldlooksverydifferentcolorandappearance, soat a glanceifwedo notknowhis keywould be

verydifficulttodeterminethe typeandname ofeach ofthevariousigneous rocks. Butit

becomeseasierwhen youhave readand understandcarefully. Igneous rockscan be determinedbased

on thenameandtypeof structure, textureandmineral composition. After knowingthe structure,

textureandmineralcompositionand thenwe putthemin the tableDeterminationIgneous rock(one of

which is a table createdby arockthat isWalter. T.Huang).

II. Sedimentary rocks

Sedimentary rock is rock formed by lithification of material origin, and the denudation or

the result of chemical reactions and the activities of the organism.Material deformation that

can rock from igneous, metamorphic and sedimentary rocks that have been damaged /

weathered due to exposure to sun, wind, rain, and so forth. Further erosion and sedimentation

basins and transported to harden / petrified / lithification.

So many kinds of sedimentary rocks and spread very widely in thickness from several

centimeters to several kilometers. Grain size can be from very fine (clay-sized) to very coarse

(size> 64 mm, eg on the stone breccia or conglomerate). And several more processes such as

transport media, and other sedimentary structures are quite complex also has a close

connection with sedimentary rocks.

Compared with the igneous rock sedimentary rock only 5% of all existing rock in the

layer of the earth. , Of 5% is 80% of it is mudstone, sandstone 5% and 15% of carbonate

rocks / limestone. However surface spreadings of the earth, sedimentary rocks occupy 75%

of all existing rock and 25% are igneous and metamorphic rocks.

A variety of sedimentary rock classification and naming of rocks has been proposed by the

experts both classifications based on genetics (history of the formation) as well as

descriptive. Classification of sedimentary rocks is genetically expressed by WTHuang

Pettijohn 1962 and 1975 is divided into two sedimentary rocks sedimentary rocks and

sedimentary rocks clastic non clastic. Meanwhile, experts from Indonesia (senior lecturer

geology of ITB) is Prof. RP Koesoemadinata, 1980 classified into 6 sedimentary rocks based

on his description. The six groups are:

a) Sedimentary rock group dedtritus rough

b) Sedimentary rock group dedtritus smooth

c) type of sedimentary carbonate rocks

d) Sedimentary rock type silica

e) Sedimentary rock group evaporate

f) Sedimentary rocks of coal type

Sedimentary rocks are clastic sedimentary rocks formed from the deposition of detritus or

fragments of rock back home. Starting from an experienced rock from mechanical

weathering (disintegration) and chemical (decomposition). Having weathered and eroded by

subsequent sedimentation basin then transported to the little market. Once deposited in

sedimentary environment, sediment prior to stone will experience the process Diagenesa

process changes that take place at low temperatures in the sediments. During and after this

lithification is a process that converts a precipitate or sediment into sedimentary rock.

III. Metamorphic rocks

Metamorphic rocks are rocks that originate from the host rock, can be derived

fromigneous, sedimentary and metamorphic rocks derived from the metamorphosed itself.

Metamorphosis (changing shape) is a recrystallization process in the earth (at a depth of 3 km

- 20 km) which are all or mostly occur in the solid state, ie without going through the liquid

phase, of the process will form the New Structure and Mineralogy under the influence of

temperature (T) and pressure (P) is high. With T of about 200 ° - 650 ° C.

According to Winkler HGF, 1967,: metamorphism is a process that converts a rock minerals

in the solid phase due to the influence of or in response to physical and chemical conditions

in the earth, where the condition of chemical and physical conditions are different from

previous conditions. These processes do not include the process of weathering and diagenesa.

Based on the incidence and history of its formation, metamorphosed by the experts grouped

into types of metamorphosis, as follows:

1. Local metamorphosis of type

Locally there are two types of metamorphosis, namely:

Metamorphosis Contact or thermal

Caused by a rise in temperature in certain rocks. Intrusion of body heat is passed on to

the rocks around them resulting in contact metamorphose. Zone of contact

metamorphic rocks around the body is called the Regional Contact (Contact aureole)

whose effects are mainly seen in the surrounding rock. The width of the heat spreading

area ranged from several centimeters to several kilometers. At the contact

metamorphic rocks around it will turn into Hornfels (horn stone) that its structure

depends on the origin of sedimentary rocks.

Metamorphosis Dislocation / Kataklastik / Dinamo

Metamorphic rocks of this type is found in areas of dislocation, eg in the area of the

Fault. (The fault). The metamorphose process occurs at the location where the rock is

experiencing a mechanical grinding process caused by the suppression factor

(compressional) in an upright or horizontal compression. Metamorphic rocks

encountered special kataklastik Orogenesa belt path where the appointment process

was followed by a phase of folding and rocks maturation.

2. Type of Metamorphosis Regional

Regional metamorphic types, there are two types, namely:

Metamorphosis Regional / Dinamo Thermal

This kind of metamorphosis occurs in the inner crust and the factors that influence

the temperature and pressure is very high. Geographically and genetically, the spread

of these metamorphic rocks is closely associated with the activity or process of

forming Orogenesa folds of volcanic mountains, covering a vast area and is always in

the form of the mountain belt in the area Geosinklin.

Thus his close relationship with the collision of two tectonic plates, in particular

between ocean crust and continental crust. This collision will form Subduction path

(subduction zone). Metamorphic rocks on the type of Metamorphosis Regional /

Dinamo Thermal structure is characterized by Foliation (alignment of lamellar

minerals) and associated with tectonic environment.

Metamorphosis Expense / Burial

Metamorphic rock is formed by a burial process by a mass of very thick

sedimentation in a vast basin known as Basin Geosinklin. The process happened

almost nothing to do with the activities and processes orogenesa intrusion, and more

commonly known as the Process Epirogenesa.

In discussing metamorphosis, will we find the sentence: the degree of

metamorphosis. High or low degree of metamorphosis, it is associated with P and T.

Metamorphic means low degree metamorphic rocks were formed by P and T are low,

and vice versa. Just as in the igneous and sedimentary rocks, the determination of the

type and name of the metamorphic rock will based on the well of the

texture,structure and mineral composition of rocks is observed to descriptions of the

name.

Cycle rock formation

Based on the knowledge of igneous, sedimentary and metamorphic as well as the

process of its formation it becomes increasingly obvious relationship to each other

rock types.

After discussing the kinds of rocks can be made according to the scheme or the

rock cycle starting from the magma that solidifies into igneous rock weathering and

erosion then experience, experienced subsequent deposition of a sedimentary rock

change into metamorphic rocks form.

Based on the mechanism of the rock cycle in the nature can be described as follows:

a. Magma becomes igneous rock

b. Igneous rocks were transported in a liquid and be suspended then becoming sediment rock.

But sometimes consciously becoming a metamorphe.

c. Sedimentary rocks can deformed to metamorphic rocks.

d. Metamorphic rocks can become igneous rocks again through magmatic process.

C. Geomorphology

I. Hills Jiwo

Bayat area is located approximately 20 km south of the City Klaten. In the administrative

county of Bayat district. Geographically (in map sheet and the surrounding hills Jiwo) lies

between 110 ° 41'24 "E and 07 ° 49'20" LS.

Area is famous for its hills Jiwo, surrounded by alluvial plains in physiography. Including

depression zones of Central Java (Solo subzone), the south is limited by the Southern

Mountains Zone (Van Bemmelen, 1949), known as Baturagung Hills. Jiwo hills is inlier

of Pre-Tertiary rocks and Tertiary sediments around Quartenary, mainly composed of

fluvio-volcanic sediments derived from G. Merapi. The highest elevation of the peaks are

no more than 400 m above sea level, so that the hills is a low hill. Jiwo hills are divided

into two regions, namely JiwoJiwo West and East are both separated by the River

Dengkeng the antecedent. The river itself flows around complex DengkengJiwo West,

originally flowing in the direction of South-Southwest, turned toward the East and the

North cut off the hills and then flows towards the Northeast. Dengkengriver is the main

dryer from the lowlands around the hills Jiwo.Gambar 4.2. Physiographic division Bayat

area where East and West Jiwo hills separated by the River Dengkeng.

This was originally a low-lying swampy area due to water flowing from the valley of G.

Merapi held by the Southern Mountains. These puddles, in the northern hills of sand Jiwo

precipitate derived from the lava. Whereas in the south or in the grooves in the hills Jiwo

is still water in the form of deposits of black loam, a fertile sediment that Merapi is dried

(reclaimed) by the Dutch colonial government to serve the plantation. Reclamation is done

creating channels that be dammed high enough so that water coming from the direction of

G. Merapi will be collected in the river while the low-lying areas of the original form of

the marshes turned into dry land used for plantations. Much of the area's original

rawayang left in an area surrounded by Puncak Sari, Monument, and the ax in the West

Jiwo, known as the Swamp Jombor. Swamp that serves as the tendon was left for the

plantation of blood irrigation in the plains north of East Hills Jiwo.

To drain water from the swamp, made the artificial channel of the Southwest corner of the

swamp through the hills of metamorphic rock in G. Pegat flows east through the village of

Sedan and the river cut through the aqueduct next Dengkeng in southern of Jotangan again

to the east.

The hills are composed of limestone hills extending to the back showed a blunted so that

the appearance of stem-peak is not so obvious. Foothill cliffs not so plot-plot terbiku not

often found (Bawak-Temas hills in the East and Tugu-Kampak in the West Jiwo). For the

region composed of metamorphic rocks foothill show more tangible relief with cliffs

terbiku strong. The yield strength of the results of the process sediment accumulation

result of erosion at the foot of these hills are known as colluvial. The tops of hills

composed of metamorphic rocks stand out and some of them tend to be shaped like a cone

peak and peak Semanggu-Jabalkat. Strong relief in this area was found from the East Jiwo

Konang peak towards the east up to the top Semanggu and Jokotuo. Pendul area around

the summit is the only body of the hill which is entirely composed of igneous rocks.

Morphology is quite rough conditions similar metamorphic hills, but relief is not as strong

as indicated peak metamorphic hills.

II. Regional West Jiwo

West Jiwo consists of a row of hills G. Axes, G. Monument, G. Sari, G. Kebo, G.

Peacock, G. Scratches, and G. Jabalkat. G. Ax and G. The monument has a layered

limestone lithology, yellowish white, compact, thick layer of 20-40 cm. In the area of G.

Ax is mostly limestone is a massive body, suggesting an association with the complex

reef (reef). Between G. Monument and G. Sari limestones are having direct contact with

metamorphic rocks (mica schist).

Jiwo area West has hilltops north-south trending, represented by the peak Jabalkat, Kebo,

Merak, scratches, Budo, Sari, and the monument to the northern most part turned to the

west, namely G. Axes.

Metamorphic rocks in this area includes the area around G. Sari, G. Kebo, G. Peacock, G.

Scratches, and G. Jabalkat the general formof mica schist, filit, and many contain mineral

quartz. Around the region G. Sari, G. Kebo, and G. Peacock on the mica schist found

chunks of andesite and mikrodiorit. The whaterred zones of spheroidal weathering are

often found at the edge of the village street. Igneous rocks is a breakthrough that the body

of mica schist. good outcrops found at the bottom of the small rivers that show stocky

columns (columnar joints).

Metamorphic rocks are found also in the form of chlorite schist filit, talc schist, garnet

mineral there, quartzite and marble in G. Scratches, and G. Jabalkat. While at the top of

the hill still found chunks of quartz conglomerate. While to the west of G. Scratches in

the rural area on the banks of Rowo Jombor still found the remnants of quartz

conglomerates and sandstones. To date the metamorphic rocks are interpreted as the age

of Pre-Tertiary rocks, sandstones and conglomerates while put in Wungkal Formation.

In this area found two inlier (isolated hill) respectively in the hills and hill Wungkal

Salam. Bukit Wungkal increasingly low due to the excavation of the population to take a

sharpening stone (stone wungkal) found on the hill.

3. Eastern Region Jiwo

This area includes the east of the Dengkeng which is a row of hills consisting of Konang

Mountain, Mount pendul, Mount Semangu, on the southern slope of Mount pendul to

reach the top, especially starting from the north of the Village Dowo found sandstone

layers, sometimes there is a £ ragmen mica schist in it. Whereas in the eastern part of

Mount pendul exposed stone gray clay-coated, hard, strong local deformation of up to

indestructible.

The relationship between rock units are still delivering a variety of possibilities for

contacts between units are sometimes covered by koluvial in the plains. Certainty

stratigraphic rock units between the barn can be believed if there has been an absolute age

measurements. Despite this variety of approaches as well as the reconstruction of

stratigraphic investigations have been carried out by experts.Jiwo hilly eastern hill-tops

have an east-west trending, represented by peaks Konang, pendul and Temas, J Mountain

and Mount jokotuo gold.

Konang mountain and Mount Semangu a body of rock-mica schist, quite well foliated,

while Mount pendul an intrusion mikrodiorit body. Metasediment Jokotuo mountain is a

rock (marble) which is found at the site of the signs of the structure of Pensee advice.

While Mount Temas is a body of layered limestone.

In the north of Mount pendul. Numulites Limestone found a rock outcrop, gray and very

compact, around the limestone contained nummulites layered sandstone. The spread of

limestone found locally-nummulites local Padasan chiefly around the village, with

branching to the north, represented by the peak Jopkotuo and Bawak.

In the north and the south east there are hills Jiwo isolated hill that stands out and alluvial

plains in its vicinity. Inlier (isolited hill) is a hill in the north and hills JetoLanang in the

southeast. Bukit Jeto generally composed of limestone, which is based Neogen is not

aligned on the metamorphic rocks, while the hill is composed entirely Lanang by Neogen

limestone.

D. Short Stratigraphic

The oldest rocks exposed in the Bayat area consists of metamorphic rocks form filtit,

schist, slate and marble. Determination of the proper age for metamorphic rocks is still

not there. The only indirect data to estimate its age is based on a single fossil that was

found by Bothe Orbitolina (1927) in the fragments that indicated the age of Cretaceous

conglomerate. Due to the age of the oldest sedimentary rocks that cover metamorphic

rocks are early Tertiary age (Eocene limestone, sandstone), the age of metamorphic rocks

is called the Pre-Tertiary Rocks.

Is not aligned on a ride in metamorphic rocks are sandstone carbonat not until little

carbon clay and stone, then on top of it covered by limestone containing abundant fossil

nummulites and the top terminated by Discocyc1ina limestone, showing the deep marine

environment. The existence of this large forminifera with plangtonik foraminifera are

very rare in the calcareous clay stone, show the age of Middle Eocene to Upper Eisen.

Officially, Eocene rocks are called Wungkal-Garnping Formation. Both the metamorphic

rocks and formation Wungkal-Gamping intermediate igneous rocks intruded by type

dioritik.

Diorite in the area is a main former of pendul Mountain, located in the eastern hills Jiwo.

This possibility of type diorite dike. Igneous outcrops in Watuprahu (north side of Mount

pendul) is stratigraphically above the Eocene rocks are tilted to the south. These igneous

rocks are stratigraphically located beneath the sandstone and limestone layer still have

sloped to the south. Determination of age in the dike! pendul intrusion by SoeriaAtmadja

et al (1991) produces about 34 million years, where the results are more or less according

to the theory Bemmelen (1949), which said that igneous rocks are the neck / neck from

the Oligocene volcano. About the genetic and the generation of diorite in the hills

magmatism Jiwo still need research that more carefully.

Before the middle of the Eocene epoch, the area began to erode Jiwo. Erosion is caused

by the removal or reduction of sea level during the late Oligocene peri ode. The process

of erosion has lowered the terse but the existing land surface, followed by a period of

transgression and deposition of rocks produces limestone started in Middle Miocene time.

Jiwo hills in the area has an equally characteristic lithology of the formation is exposed

lenih Oyo many of the Southern Mountains (and surrounding areas Nglipar-Sambipitu).

In areas Bayat no marine sediments exposed on the Formation and Formation

WungkalGampingan Oyo. The situation is different at the Baturagung Mountains to the

south. Here the thickness of rock that characterized yesterday volkaniklastikturbidit and

sediment gravity flow deposition results of other well-exposed. These differences may be

caused by a complex fault system that separates the hills of the Mountains

BaturagungJiwo who has been active since the Middle Tertiary.

During the Quaternary, the deposition of limestone has ended. Followed by removal of

the erosion process caused Jiwo Hills area turned into the terrestrial environment.

Volcanic sand from Merapi volcano is still active alluvial sedimentation processes

affecting mainly the north and northwest of the Hills Jiwo.

E. GEOLOGICAL HISTORY

Expansion of the Indian Ocean Floor

Java Island is located in the southeastern edge of the Greater Sunda (Sundaland). On the

Mainland, there are two systems Sunda plate motion; South China Sea Plate in the north

and south Indian Ocean Plate. South China Sea Plate moves to the southeast since the

Oligocene (Longley, 1997), while the Indian Ocean Plate that is moving south to north

since the Mesozoic and attack down island arc system of Sumatra and Java (Liu et al.,

1983). For Java, the largest effect is the Indian Ocean plate motion system. Therefore, in

studying the tectonic evolution of Java is necessary to understand the development

division of the Indian Ocean floor from time to time. Before the discovery of fossils of

the central division of the Wharton Ridge, knowledge of the history of the Indian Ocean

is limited to the presence of three-phase expansion of the ocean floor since the breakup of

Gondwana continent east (Liu et al, 1983).

• The first phase of the expansion occurred in the Early Cretaceous (127 Mya) when India

separated from Antarctica and Australia in the northwest-southeast direction.

• The second phase of expansion took place between the formation of magnetic

anomalies 34 and 22 (or between 82 Mya to 54 Mya) are characterized by separate India

from Antarctica to the north and away quickly. This phase is indicated by the straightness

of the magnetic anomaly trending east-west. Then the anomaly 22 (or 54 Mya) the speed

of movement of India to the north is expected to decline significantly due to begin the

first contact occurs between the continent of India with the subduction zone in south

Asia.

• The third expansion phase, or phase of the latter, anomalies occurred from 19 (or 45

Mya) until now shown by anomaly 19 to anomaly 0 (zero) to the northwest southeast

direction that separates India and Australia from Antarctica.

Historical development of the Indian Ocean is revised by Liu et al (1983) based on the

study of magnetic anomalies Wharton Ridge, a major expansion of the southwest-

northeast trending that stops its activity on the anomaly 20 (45.6 Mya). The first

indication of the existence of the Wharton Ridge were reported by McDonald (1977, in

Liu et al., 1983). In his study of fan sedimentation and structure under Nicobar Sea,

which cover the ocean floor in the northwest of the Wharton Basin, identified a series of

bedrock altitude southwest-northeast trending below the sediment layer and name it as

the Wharton Ridge heights. He also argues that the heights or embankment represents the

central segment of the division that has not infiltrated beneath the Sunda Trench.

Based on the identification of magnetic anomalies in the vicinity of the Wharton Ridge

and the results of the DSDP (Deep Sea Drilling Project) nearby, Liu et al. (1983)

suggested the order of development of the eastern Indian Ocean as follows (Figure-27):

1. India-Australia separated from Antarctica to the northwest-southeast direction of the

magnetic anomaly M-11 (or about 127 Mya), which marks the outbreak of the ancient

continent of the eastern Gondawana.

2. In the Middle Cretaceous, the formation of anomalies and anomalies M-0 34 (or

between 110-82 Mya), plate reorganization occurred on a large scale first. Relative

movement between India and Antarctica turned into a north-south trending and

Australia began to separate from Antarctica.

3. In the Late Cretaceous, during the formation of anomaly 34 to anomaly 22 (or between

82-54 jt), India continued to move north quickly, while Australia is moving away from

Antartika slowly. At the triple junction formed at the place where transform faults

trending 86 ° E of north-south division of India together with the center of Antarctica

is trending east-west. At that time India and Australia are different in the two plates

separated by a central division of Wharton.

4. Between the formation of anomaly 22 and anomaly 19 (or between 54jt - 45 jt), a

second plate reorganization occurred prominently marked with the reduced speed of

movement to the north of India. Expansion activities along the Wharton Ridge quit or

die shortly after formation of anomaly 19 (or 45 jt). Markedly reduced northward

motion of India and the demise of the Wharton Ridge is interpreted as a sign of the

Indian subcontinent's first contact with the subduction zone in south Asia at 54 Mya.

5. After the formation of anomaly 19 (around 45 Mya), the activity center in the southern

division of Australia (SE Indian Ridge), which separates India, Australia and

Antarctica, lasted until now. At that time, the center has been the demise of the

division Wharton, India and Australia are on a single plate and together move

northward. In the western continent of India continued to move north, hit with a hard

(hard collision) to form the Himalayan Mountains of Asia, while in the eastern Indian

Ocean plate continues attack in the Sunda Trench.

Tertiary Tectonic Evolution of Java

Java is one of the islands in the Sunda arc has a history of active geodinamic, which, if traced to

its development can be grouped into several tectonic phases starting from the Late Cretaceous to

the present (Figure-28).

Late Cretaceous - Paleocene

Early tectonic phase occurred in the Mesozoic when the movement of the Indo-Australian Plate

to the north east produced under the Sunda subduction along the sutures Karangsambung

MicroplateMeratus, and followed by phase strain (rifting phase) during the Paleogene in the

formation of a series of Horst (altitude) and graben (lower). Late Cretaceous magmatic activity

can be followed continuously from the Sumatra-Java SE-Southeast Kalimantan. Arc basin

formation front (fore arc basin) developed in the southern regions of West Java and South Serayu

in Central Java. Approaching Late Cretaceous - Paleocene, a separate fragment of the Gondwana

continent, close to a subduction zone-MeratusKarangsambung. The presence of allochthonous

micro-Continents in Southeast Asia region has been reported by many authors (Metcalfe, 1996).

Continental basement is located east of the subduction zone-MeratusKarangsambung Makassar

Strait and the pillow are identified in the Well Fox-1 (Conoco, 1977) in the form of granite at a

depth of 5056 feet, while the nearby wells penetrating Taka Talu-1 diorite basement. Docking

(feel patnya) microcontinent fragments on the eastern edge of Sundaland caused the death of a

subduction zone-Meratus Coral grafting and the lifting of the subduction zone resulted in

Meratus Mountains (Figure-29).

Eocene period

(The period of extensional / strain)

Between 54 Mya - Mya 45 (Eocene), occur in the Indian Ocean plate reorganization

characterized by a striking reduction in the speed of movement to the north of India. Expansion

activities along the Wharton Ridge quit or die shortly after formation of anomaly 19 (or 45 Mya).

Markedly reduced northward motion of India and the demise of the Wharton Ridge is interpreted

as a sign of the Indian subcontinent's first contact with the subduction zone in south Asia and

caused the tectonic strain (extension tectonics) in most parts of Southeast Asia are characterized

by the formation of primary notches (Basin -basin: Natuna, Sumatra, Sunda, East Java, Barito,

and Kutai) and the sediment is known as syn-rift sediments. Extension tectonics spreadings are

associated with movement along the regional fault that existed before the

microcontinentfragments. Configuration of basement structures affecting the syn-rift Paleogene

basins on the southeastern edge of Sundaland

F. ECONOMIC GEOLOGY

Excavation materials are divided into three groups:

a. Strategic group minerals are:

petroleum, liquid bitumen, wax, natural gas.

solid bitumen, asphalt;

anthracite, coal, coal-young;

uranium, radium, thorium and radioactive materials other minerals;

nickel, cobalt;

tin.

b. Group of minerals that are vital:

iron, manganese, molybdenum, chromium, tungsten, vanadium, titan;

bauxite, copper, lead, zinc;

gold, platinum, silver, mercury, diamonds;

arsin, antimony, bismuth;

yttrium, rhutenium, cerium and other rare metals;

beryllium, corundum, zircon, quartz crystals;

cryolite, fluorpar, barite;

iodine, bromine, chlorine, sulfur;

c. Group of minerals that do not belong to this class a or b is:

nitrates, phosphates, phosphate, rock salt (halite);

asbestos, talc, mica, graphite, magnesite;

yarosit, leusit, alum (alum), ocher;

gemstones, semi precious stones;

quartz sand, kaolin, feldspar, gypsum, bentonite;

a pumice stone, mattress, obsidian, perlite, diatomaceous earth, soil

absorption (Fullers earth);

marble, slate;

limestone, dolomite, calcite;

granite, andesite, basalt, trakhit, clay, and sand does not contain all the

mineral elements of a class A or class B significant amount in terms of the

mining economy.

CHAPTER IV

GEOLOGICAL STRUCTURE

Geologic structure in question is the structure formed after the rocks formed and is the

result of deformation due to forces acting on a rock in a long time. Deformation in rocks and the

earth's crust can take place both fragile (brittle) or continuously (ductil).

The resulting structures can be hefty (joint), faults (fault), folds (fold), foliation

(foliation), and lineation (lineation). The presence of robust, fault and foliation on the rocks can

weaken the strength (strength) of rock, while the shift faults (tectonic) can cause earthquakes,

tsunami, or changes in topography that could sink a coastal area or in another landslide that

could form a natural weir a river flow resulting in flooding. It all can be said is a common natural

process, but if there is already a human element in it, including infrastructure, so then it is called

a disaster. In disaster management, efforts to minimize the negative impact of an event be

included as a mitigation effort.

The earth's surface is the interaction between the processes that originate from within the

earth (the process of formation of rocks and geological structures) with the origin outside (the

hydrologic cycle, wind, and climate). The results of these interactions is found in the earth's

surface the appearance of mountains, hills, valleys, steep cliffs, vast plains, plateau, commonly

referred to as the landscape. General classification of the landscape based on slope and location

of the height (measured from sea level). Sea level is considered as the limit equilibrium; if it is

above sea erosion likely will occur, while below sea sedimentation will occur. Slope as one of

the important appearance in the landscape, in the length of time it will evolve and the surface

material on the slope will move down because of gravity. Dynamic factors of the formation of

the landscape can be divided into passive factor and active factors. Factor closely related to the

passive state of the subsurface layer and its products at the surface. It is highly influenced by the

type of lithology (rock), the slope lithology (straight lithology, angled or horizontal), structure

(there are many cracks), and its position in the landscape (in the valleys, cliffs or peaks). Active

factor closely related to the agents of erosion, namely: climate, active tectonics (earthquakes),

and changes in slope angle, as well as biological processes.

Stump and Geological Structure of Fault

Geological structures that play a role in many revealed by geological disasters are robust

and fault. Stump (joint) is simply regarded as irregular-shaped cracks in the rock that does not

show (as seen with the naked eye) has been movement on both sides.

Generally divided into four (McClay, 1987), the muscular pull (an open fracture

extension due to a force directed perpendicular to the direction of fractures), muscular shear

zones (usually in pairs is a set and straight, there is a shift caused by the compression force),

robust hybrid (Shown as muscular shear zones are open, a combination of shear zones stocky and

muscular tension), and irregular muscular pull (the stout, irregular, often a result of hydraulic

fracturing). Muscular presence in the rock can increase the porosity of the rock, so as to save

water (the aquifer) or hydrocarbons (as a reservoir), the reverse is also weakened the power of

rock. Muscular presence near the surface can also speed up the process of rock weathering.

Fault/fracture(fault), known also as the fault is a fracture in the rocks which have shown

symptoms of the shifton both sides of the fracture area(Simpson, 1968). Based kinematikanya, in

outline, divided into section down, reverse fault, and faults hear(Fig.5). Faultin question is the

shift caused by tectonic forces.

CONCLUSION

Geological structure is the science of geology that studies the origin of the earth's crust, and the

factors that classified into two:

A. Rock factor

B. Style factors consisting of:

1. Style or the style of compressive stress

2. Tensional pull of the style or styles

3. Shear forces or coupling

Of the above factors can cause a geological structures that are classified into two:

A. The primary structure

B. Secondary structure consisting of:

1. Muscular structure or fracture

Caused due to forces acting on the rocks. Muscular structure consists of:

a. Stump press (joint tension) is shaped like scissors / pairs.

Usefulness stout tap in the field of geology:

i. For the measurement data is entered into the tabulation or table in order to

manufacture the fan diagram. Diagram of the fan itself is to know the direction

of the force main () which causes the formation of geological structures (faults,

sturdy, folds) in the area.

b. Stump tensile (shear joint) fractures form fracture-containing minerals.

Usefulness of muscular pull in geology:

i. To search for materials that have economic value that is usually contained in

the stout.

2. Structure of the fault or faults

Is the structure of fractures in rocks that have undergone a shift along the field crack.

Fault structures are structures that are very important because it relates to the

occurrence of earthquakes and mineral deposits and trapped oil. Fault can be divided

into three, namely:

a. Normal fault (normal fault)

Is a fault with the hanging wall moves down relative to the foot wall. A normal

fault can be caused by a vertical compressive force or by a horizontal traction force.

Block bounded on both sides by normal faults are called "graben" if it is a valley

and is called "Horst" if it is sembulan or altitude

b. Parallel faults (strike-slip faults)

Is the fault that moves parallel to the fault arc. Cesarean section is commonly

referred to as shear horizontal, consisting of two kinds of shifts:

1. Right-fault shear horizontal (right-lateral-fault)

2. Horizontal shear faults left (left-lateral-fault)

Faulting generally horizontal sliding of the fault.

c. Reverse fault (reverse fault)

Is a fault with the hanging wall moves up relative to the foot wall. A reverse fault is

generally caused by the compressive force is directed horizontally. If the reverse

fault has a fault area with a gentle dip (<450) then the fault is called fault

containment or "thurst fault"

3. The structure folds (fold)

Fold structure is a structure shaped like a wave that commonly occur in layered rocks

subjected to compressive horizontal / vertical.

Crease in the description of the structure consists of two forms:

A. Anticline

The folds are upward curved shape due to endogenous got style.

B. Syncline

Shaped curved section folds down due to endogenous got style.