Sedimentological Study of Ngrayong Formation at …eng.unila.ac.id/wp-content/uploads/2019/01/CR-1-38.pdfUplift causes the quartz-sandstones with coal layer intercalation and gypsum,

Prosiding Semnas SINTA FT UNILA Vol. 1 Tahun 2018

Riset PT-Eksplorasi Hulu Demi Hilirisasi Produk

Bandar Lampung, 19 Oktober 2018

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Sedimentological Study of Ngrayong Formation at Candi and Surrounding Area, Todanan

Blora, Central Java

Rezky Aditiyo1 , Djuhaeni2

, Bambang Priadi2 , Supriyanto 1,* 1University of Indonesia, Gedung A FMIPA UI, Beji, Kota Depok, Jawa Barat 16424.

2 Bandung Institute of Technology, Teknik Geologi, Jalan Ganeca 10, Bandung, Jawa Barat 40132

*Corresponding Author: [email protected]

Abstract. Research area is located on Candi Village, Todanan District, Blora Regency, Central Java, which is

geographically 111010’30” – 110012’00” LS dan 6052’42” – 6055’00” BT. The area is about 12 km2. Stratigraphy unit

consists of four stratigraphy units. Tawun Formation claystone Unit was deposited on the late of Early Miocene. Ngrayong

sandstone Unit was lying on it, deposited conformably on the early of Middle Miocene. Then on the late of Middle Miocene

until the early of Late Miocene, Bulu Formation limestone Unit was deposited unconformably on middle neritic until outer

neritic environment. Wonocolo Formation Marl Unit, then deposited on the Late Miocene. Geological structure found

were anticline and strike slip fault, had been developed by N-S tectonic force since Pliocene until Pleistocene with a NW–

SE and NE-SW trend. Uplift and erosional process then created nowadays morphology. Ngrayong Formation consists of

quartz sandstone, claystone, and also limestone, divided by three parts, there are: Lower Ngrayong Formation, Middle

Ngrayong Formation, and Upper Ngrayong Formation. Grain size indicating shallow marine facies (surfzone-offshore),

paleontology analysis shows that deep water fossils and shallow marine fossils were mixed together, and also cruziana

trace fossil. Microcline were found in petrography analysis in quartz sand. Based on facies association, Ngrayong

Formation in Candi Area was being interpreted as shallow marine deposition in littoral to inner neritic zone.and

sedimentational pattern and grain size analysis show Ngrayong Formation on Candi area obviously was deposited on

littoral until inner neritic zone. Deep marine fossils that were mixed in shallow marine association were interpreted as

reworked fossils that came from Tuban Formation below Tawun and Ngrayong Formation.

Kata kunci: Ngrayong, Candi, Stratigraphy.

INTRODUCTION

Research area is located on Candi Village, Todanan District, Blora Regency, Central Java, which is geographically

111010’30” – 110012’00” LS dan 6052’42” – 6055’00” BT. It covers an area of approximately ± 12 km2 (Figure 1).

The East Java Basin is situated on the southern margin of the stable Sunda craton and covers an area of approximately

50,000 sq km (Mudjiono and Pireno,, 2001). The Tertiary stratigraphic record of the East Java Basin suggests periods

of relative quiescence alternating with periods of tectonic activity (Simo, et al., 2012). In the Middle Miocene, a

regression phase occurs due to uplift that covering a large area in Indonesia. Uplift causes the quartz-sandstones with

coal layer intercalation and gypsum, Ngrayong Formation, was exposed. This formation was deposited in fluvial (non-

marine) environments, tidal areas to middle neritic.

Figure 1. Administrative map of Central Java Province. Research area are shown with purple rectangle

Stratigraphy unit of the study area consists of four stratigraphy units. Tawun Formation claystone Unit was

deposited on the late of Early Miocene. Ngrayong Formation Unit was deposited conformably on the early of Middle

Miocene. Then on the late of Middle Miocene until the early of Late Miocene, Bulu Formation limestone Unit was

deposited unconformably on middle neritic to outer neritic environment. Wonocolo Formation Marl Unit, the younger

unit, deposited on the Late Miocene. Geological structure found were anticline and strike-slip fault, had been

developed by N-S tectonic force since Pliocene until Pleistocene with a NW–SE and NE-SW trend. Uplift and the

erosional process then created nowadays morphology. The geomorphology unit comprises Anticline Hill Unit,

Hogback Ridge Unit, and Homocline Valley Unit.




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Figure 2. General stratigraphy of research area. Early Miocene Tawun Formation are the oldest formation can be

recognized, while Late Mioccene Wonocolo Formation are the youngest that are exposed

The Ngrayong Formation was subject to be questioned to who have been working in the East Java Basin, especially

on Cepu, including Candi area. The opinion was about differences in the depositional environment between Ngrayong

as shelf and Ngrayong as deepwater/deep marine sediment. Previous field based study showed that Ngrayong

Formation was deposited on beach – tidal deposit (Poedjoprajitno and Djuhaeni, 2006). Contrary to Ardhana (1993),

Ngrayong Formation was deposited on shelf to submarine fan. This study was therefore conducted to investigate the

depositional environment of The Ngrayong Formation, based on field investigations involving grain size analysis,

petrographic analysis, micropaleontological analysis, and facies analysis.

RESEARCH METHODS

This research is based on field investigations involving facies analysis, grain size analysis, petrographic analysis, and

micropaleontological analysis. Lithofacies, fossils, and grain size analysis can produce comprehensive data of facies

associations that can reflect a certain depositional environment. Relative position stratigraphically from existing data

can provide information for interpretation Ngrayong depositional environment changes. Based on the analysis of

Ngrayong Formation on Candi Village and its surroundings, the author divided Ngrayong Formation based on its

facies association: Lower Ngrayong Formation, Middle Ngrayong Formation, and Upper Ngrayong Formation.

Grain size analysis sampling method was taken from outcrop of quartz-sandstone in the study area. If the outcrop

has a vertical extent stratigraphically more than one meter, sampling was carried out for each meter. Total fifteen

samples were taken for grain size analysis Petrographic analysis was carried out to determine the composition, texture,

type of porosity, and fossils content. Micropaleontology analysis was conducted to determine foraminifera

microfossils that will be used for interpretation of Biozone Zonation (Blow, 1969) and depositional environments

(Tipsword, 1966).

RESULTS AND DISCUSSION

Ngrayong Formation is characterized by quartz-sandstone with predominantly non-carbonated quartz fragment, good

sorting, grain shape angular - subangular, closed fabric, good porosity, easy squeezed, very fine sand - fine sand;

intercalated with limestone and claystone on the lower part, then become limestone dominant on the upper part.

Ngrayong quartz sandstone in the study area develops from the upper part of the Tawun Formation and the middle to

upper part of the Ngrayong Formation.

Based on the analysis of Ngrayong Formation in the Candi area and surrounding area, the author divides Ngrayong

Formation into three parts based on the facies association : Lower Ngrayong Formaition, Middle Ngrayong

Formation, and Upper Ngrayong Formation. Detailed stratigrapy are shown in Figure 3.

Lower Ngrayong Formation

The lithological characteristics of the Lower Ngrayong Formation consist of quartz sand, followed by clastic limestone

at the upper part. quartz-sand has the characteristics of low cemented quartz fragments dominant (loose sand), reddish-

white, non-carbonated, good sorting, subrounded-rounded grain shape, good porosity, fine sand-medium sand, mineral

content consisting of quartz and microcline (Figure). there were some root fossils identified in sand-quartz outcrops




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in the south of the Candi Village. The sandstone is clean sand with very little cement content, so that its textural

maturity of rocks are mature - super mature. This can be classified as Quartz Arenite. Thin section analysis show

clastic texture, well sorted, closed fabric, long contact, mineral content consist of quartz, plagioclase; very fine sand -

fine sand (0.015-0.25mm), subangular-angular grain shape, and intergranular porosity.

Based on limestone outcrops observation at the R1C location around Ngampel Village, Glauconitic Foraminifera

Packstone is reddish-white, clastic texture, poorly sorted, open fabric, consists of fossil fragments of foraminifera,

intact and cracked form, and siliciclastic in the form of quartz, glauconite with a size of 0.1-1 mm. The matrix consists

of carbonate mud and cement consists of calcite sparry. Porosity types are interparticle and intraparticle.

Figure 3. Detailed stratigraphy of Ngrayong Formation, integrating facies, fossils, and grain size analysis, shows

litoral – inner neritic depositional environment association

Figure 4. Quartz arenite was recognized from R6I sample. Quartz dominant and minor plagioclase and microcline

(D3). Sometimes overgrowth secondary quartz are found

0 0,5 mm 0,5 mm 0




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Based on grain size analysis of three quartz sand samples, is known that the three samples were deposited in the

surfzone or near shore depositional environment. Deposition mechanisms in this zone can be seen in the graph that

the traction flow is more involved rather than the suspension current mechanism. Graph lines in the traction population

(rolling/sliding and saltation) is not too gentle qualitatively, indicating that sorting is quite good on the deposition of

sand-quartz. Association of Lower Ngrayong Formation shows littoral zone to the edge neritic depositional

envvironment.

Middle Ngrayong Formation

The lithological characteristics are clastic limestone and claystone at the bottom, then quartz sand with clastic

limestone and intercalated claystone on the upper part. Quartz sand with gray-white color, non-carbonate, good

sorting, subrounded-rounded, closed fabric, fine to medium sand, dominant minerals are loose quartz minerals with

few microcline. Reddish-white clastic limestone, medium sorting, angular-subrounded, opened fabric, medium sand-

coarse sand. Claystone with gray color, compact, very fine grained. Vertical succession shows a coarsening upward

pattern.

A thin section of sand-quartz called quartz arenite has characteristic clastic texture, well sorted, closed container,

grain contact long contact, consisting of quartz, plagioclase, very fine sand-fine sand (0.015-0.25mm), subangular-

angular, intergranular porosity.

Foraminifera wackestone has clastic texture, poorly sorted, opened fabric, consisting of foraminifera fragments

(Lepidocylina, Katacyclopeus annulus, Amphistegina sp.), medium sand-fine sand (0.2-0.9mm), rounded-angular

grain shape. The matrix consist of micrite. Cements are sparry calcite. Porosity are Interparticles and moldic.

Micropaleontological analysis on Middle Ngrayong Sandstone represented by R6J samples showed the presence

of Quinqueloculina sp., Operculina sp., Rotalia sp., and Elphidium sp., showing association of littoral - middle neritic

environment. Grain size analysis on Middle Ngrayong Sandstone section was carried out on twelve quartz sand

samples. Stratigraphically, it was interpreted that there is a change from the lower shoreface to foreshore and surfzone.

Based on the facies association, Middle Ngrayong Formation was deposited in edge neritic environment.

Upper Ngrayong Formation

The Upper Ngrayong Formation consist of clastic limestones intercalated with sandstone and claystone, showing

coarsening upwards succession. Clastic limestone has clastic texture, poor sorting, subangular-subrounded, opened

fabric, medium porosity, compact, contains fossils such as Lepidocyclina sp., red algae, and Katacycloclypeus

annulatus. Claystone has a gray color, carbonate, rarely intercalated with sandstone with Brachiopods shell fragments,

Turritella sp., foraminifera, and pyrite minerals. Clastic limestone has the characteristics of gray-white color,

sometimes sandy, poorly sorted, subangular-subrounded, medium sand-coarse sand. Foraminifera are

Katacycloclypeus annulatus, Lepidocyclina sp., and Amphistegina sp. While sandstones has a grayish-black color,

medium sorting, opened fabric, fine sand-coarse sand, compact, fragments consists of mineral quartz, mica, and shell

fragments.

Benthic foraminifers in R3E, R5D, and R5C samples were observed along with their bathymetry (Tipsword, 1966)

are Cibicides sp. (middle neritic), Quinqueloculina sp. (littoral), and Elphidium sp. (edge neritic) in R3E sample.

Quinqueloculina sp. (littoral) and Rotalia sp. (littoral) in the R5D sample, then Cibicides sp. (middle neritic),

Operculina sp. (middle neritic), and Elphidium sp. ( edge neritic) in the sample R5C. Whereas in the R3C sample can

be observed benthonic foraminifera such as Gyroidina sp. (upper bathyal), Operculina sp. (middle neritic),

Quinqueloculina sp. (littoral), Elphidium sp. (edge neritic), and Bolivina sp. (outer neritic). Then in the R3A sample

shows the presence of Cibicides sp. and Bolivina sp. cruziana fossils were also found. Cruziana indicates the offshore

environment.

Deep marine benthonic foraminifera were found in shallow marine fossils association. This was interpreted as a

reworked fossils. Depositional sequences from Tawun Formation to the Wonocolo Formation show the transgressive

depositional series. Facies association of shallow marine deposits of Ngrayong Formation, indicates that a certain

sedimentation processes occurs which made deep marine fossils mixed with shallow marine fossils association. Deep

marine fossils were interpreted as reworked fossils from Tuban Formation that was deposited on Early Miocene on

deep marine setting. Based on the comprehensive data described earlier, it can be concluded that Ngrayong Formation

in Candi area and its surroundings are deposited in the littoral zone to the edge neritic.




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Figure 5. Summary of Micropaleontogy analysis. Foraminifera associations show deepening upward trend from

Tawun to Wonocolo Formation. O : rare (1-3); + : few (4-10); | : common (11-25); -: barren

CONCLUSION

Ngrayong Formation could be divided to three parts based on facies association, there are Lower Ngrayong Formation,

Middle Ngrayong Formation, and Upper Ngrayong Formation. Based on lithological characteristic, grain size analysis,

petrography, and microfossils analysis, it can be concluded that Ngrayong Formation in Candi and its surrounding

area was deposited at shallow marine from litoral to inner neritic zone. Deep marine fossils in shallow marine fossils

association were interpreted as reworked fossils from older formation (Tuban Formation).

transisi

neritik pinggir

neritik tengah

neritik luar

batial atas

N14

R2

BG

lob

oro

talia

men

ard

ii+

OO

+I

O+

O+

OO

N13

R2

AG

lob

oro

talia

foh

siI

+O

++

OO

OI

+O

O

N12

R3

AG

lob

oro

talia

foh

si+

++

O+

O

R3

EO

+O

+I

+

N9

R6

JO

rbu

lina

un

iversa+

IO

+I

O+

O

R1

B-

-R

1A

--

Cassidulina sp.

Miosen Tengah Miosen Tengah Miosen Akhir

R3

C

R5

C

Batugamping

Formasi

I

Ngrayong

I

I

I

I

O

+

+

Globigerinoides obliquus

Globigerinoides trilobus immaturus

Globorotalia obesa I

Globoquadrina altispira

Globoquadrina dehiscens

I

Spesies Index

Orbulina suturalis

O

Globigerinoides trilobus trilobus

Globigerinoides sacculifer

+

I

I

I

I

OG

lob

oro

talia

aco

staen

sis R

2C

I

R5

D

+

I

O

Oolina sp.

I

Elphidium sp.

+

Bolivina sp.

O

I

I

O O

Nodosaria spp.

Globorotalia acostaensis

Gyroidina sp.

Rotalia sp.

Operculina sp.

Kelimpahan Foraminifera Benthonik

Nonion sp.

Bulimina sp.

Quinqueloculina sp.

Cibicides sp.

Texturalia sp.

O O

O

O

O

I

Amphistegina lessonii

+

I

Uvigerina sp.

I

+

Umur

Zonasi Planktonik (Blow, 1979)

Globigerina praebulloides

Globigerina bulloides

Orbulina universa

Globorotalia fohsi

Lingku

nga

n p

engen

da

pa

n

Kelimpahan foraminifera planktonik

I

I

Satuan batuan

Lokasi sampel

+ I

I

O OIO

R4

J

R4

K

R7

E

I

I

+

I

II

Napal

+I

I

I

+

+

+O

O

+I

+

I

+

Tawun Wonocolo

Batupasir

Globogerinoides subquadratus

+ I

Globrotalia menardii

Batulempung

Glo

big

erina

pra

ebu

lloid

es

Bulu

+

N10-N11 N 17N16

O




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ACKNOWLEDGEMENT

We would like to thank Faculty Member of Mathematics and Natural Sciences University of Indonesia. Special

appreciation for Dr. Djuhaeni and Dr. Bambang Priadi (Geology Department of Institut Teknologi Bandung) for great

technical discussions.

REFERENCES

Ardhana, W. 1993. A Depositional Model for The Early Miocene Ngrayong Formation and Implication for

Exploration in The East Java Basin. Jakarta: 22nd IPA Proceedings.

Blow, W. H., 1969. Late Miocene to Recent planktonic foraminifera biostratigraphy: In Brönnimann, P. and Renz, H.

H. (eds.), Proceedings First Int. Conf. on planktonic microfossils, Geneva, 1967, v. 1, pp. 199-422.

Mudjiono, R. and Pireno, G.E.. 2001. Exploration Of The North Madura Platform, Offshore East Java, Indonesia.

Jakarta: 28th IPA Convention & Exhibition Proceedings.

Simo, T., Sekti, Rizki P., Hakiki, F., Sun, M., Myers., R. Fullmer., S. 2012. Reservoir Characterization and Simulation

of an Oligocene-Miocene Isolated Carbonate Platform: Banyu Urip Field, East Java Basin, Indonesia. Search and

Discovery Article.

Soedjoprajitno, S and Djuhaeni. (2006). Unit Genesa Pasir Ngrayong di Desa Ngepon Jatim, Cekungan Jawa Timur

Utara. 38th Geologi Bulletin.

Tipsword, H. L., F. M. Setzer, and F. L. Smith, Jr.. 1966. Interpretation of depositional environment in Gulf Coast

petroleum exploration from paleoecology and related stratigraphy: Transactions of the Gulf Coast Association of

Geological Societies, vol. 16, p. 119–130.

Documents

Sedimentological Study of Ngrayong Formation at …eng.unila.ac.id/wp-content/uploads/2019/01/CR-1-38.pdfUplift causes the quartz-sandstones with coal layer intercalation and gypsum,