INTRODUCTION TO THE GEOLOGIY & STRATIGRAPHY OF THE NE JAVA BASINCOMPILED BY

WARTONO RAHARDJO

Senior Lecturer (Retired)DEPARTMENT OF GEOLOGICAL ENGINEERINGUNIVERSITAS GADJAH MADA

2015

LOCATIONJakartaYogyakartaNE Java Basinal AreaArea of Mapping 2015

PHYSIOGRAPHY OF SE ASIA

mod. from Pertamina and Beicip (1982, 1985) by Satyana, 2003North East Java BasinSEDIMENTARY BASINS OF INDONESIA

L A U T J A W A1608010203040607050208091113181410081220192115161723222524BADAN PELAKSANA KEGIATAN USAHA HULU MINYAK DAN GAS BUMIEks. BPMIGAS, Juli.2005U : ..Petronas Car. Muriah (Eks)Camar Res. Bawean (Prod) Petronas Karapan (Eks)ConocoPhilips Ketapang (Peta Inset7755112112114114116116Petronas Car. Madura (Eks)Anadarko Madura (Eks.)EMP Kangean (Prod.)242223Easco E. Sepanjang (Eks.)2502PRODUCING BLOCKEXPLORATION BLOCKWORKING AREA MAP Satyana (2005)

1. Quaternary volcanoes2. Alluvial plains of northern Java3. Rembang Madura anticlinorium4. Bogor, North Serayu, and Kendeng anticlinorium5. Domes and ridges in the central depression zone6. Central depression zone of Java and Randublatung Zone7. Southern Mountainsvan Bemmelen (1970)Area of Mapping 2015PHYSIOGRAPHY OF JAVA ISLAND

Manur and Barraclough (1994)Area of Mapping 2015GENERAL TECTONIC SETTING OF JAVA

STRUCTURAL GEOLOGY OF EAST JAVAMapping Area

After Musliki (1991)RembangBloraSEMARANGKENDENG ZONEREMBANG ZONERANDUBLATUNG ZONEJAVA SEAStructural style of Rembang areaRMKS Fault ZoneKerangka struktur daerah kerja

REGIONAL STRATIGRAPHY

Kujung Formation

The Kujung Formation con-sists of marl interbedded with thin fossiliferous sand-stone and limestone, with larger forminifera, algae and coral debris on the basal part, The upper part : monotonous marl intercalated with bio-clastic as well as reefal lime-stones. The basal part :Kranji mem-ber, overlain by Prupuh member. The Kujung was deposited in a deep marine environment during the Late Oligocene.Prupuh Member In the mapping area this unit consists of monotonous marl with limestone intercalations. The Prupuh was accumulated in outer neritic environments during the Late Oligocene.KUJUNG FORMATION

Tuban Formation

The Tuban consists of interbedded of packstone-wacke-stone, with abundant foraminiferal fossils, coralline and algal fragments and monotonous claystone layers with occasional limestone intercalations. Deposited in a deeper marine during the early Miocene.

Grades southward into shale and claystones, deposited within middle to outer shelf environments, which com-prise the Tawun Formation.TUBAN FORMATION

Tawun FormationIt consists of interbedded between sandy carbonace-ous shale with sandstone and bioclastic limestone. The limestone contains abundant larger foraminifera Lepidocy-clina, Cycloclypeus (Katacy-cloclypeus) annulatus. The shale is light grey, well bed-ded with thickness exceeds 30 m. Tawun Formation was de-posited in shallow, outer shelf of an open marine envi-ronment during Early to Middle Miocene age.TAWUN FORMATION

NGRAYONG FORMATION Ngrayong FormationNgrayong is a red to yellowish red sandstone, showing a soft sediment deformational structures and scattered vertical burrows of Ophiomorpha. Ripple mark and gypsum needles are found in the lower part of this Formation. Upward the Ngrayong is intercalated by thin bedded clastic limestones with abundant larger foraminifera. This unit was initially deposited in an intertidal environment which transgress into tidal bar or shoreface (red sand-stones) then deepened into to the middle shelf environment during early Middle Miocene

BULU FORMATION Bulu FormationBulu Formation consists of calarenites ( bedded grainstones and wackstones) with intercalations of sandy marls. Larger foraminifera fossils are abundant locally. The limestone consistscarbonate lithoclasts, small and larger forami-nifera with minor amount of quartz, feldspar and glauconite. This formation has Middle Miocene age and was deposited in a shallow open marine environment.

WONOCOLO FORMATION Wonocolo FormationThis formation consists of generally of interbedded between fossiliferous sandy marls and clayey marl rich in planktonic foraminifera with thin bedded gray fossilliferous calcarenites. ..

Sandy limestone and calcareous sandstone of 5 20 cm thickness are present in the lower part. The age of this formation is Middle to Late Miocene, zone N14N16

LEDOK FORMATION Ledok FormationThe Ledok consists of interbedded glauconitic sandstone with platy calcarenite and marl intercalations. The sandstone is greenish to brownish, fine to medium grained, moderately sorted quartz, calcitic fragments and glauconites. The lower part is finer than the upper part. The upper part of the Ledok is charac-terized by bioturbation and large cross bedding, indicating outer to inner neritic environments. To the north, this formation probably grades into limestone facies (Paciran Formation). Total thickness of the formation attains 230 m at the type lo-cality. Formation was deposited during the Late Miocene (N17 N18).

MUNDU FORMATION Mundu FormationThis unit consists of marl and shale. The white-grey to yellowish white massive marl is abundant of planktonic foraminifera and minor glauconite dominates the lower part of the Mundu. The formation thickens southward up to 700 m and was deposited

in deep marine. The occurence of planktonic foraminiferal assemblage points out an age which ranges from Miocene to Pliocene (N17-N20).In some places, the upper part of the formation gradually develops into interbed-ded fossiliferous, greenish-gray sandy marl of the so-called Selorejo Member.

PACIRAN FORMATIONPaciran FormationThis Formation consists of massive reef and reefal limestone which typically weather into karren surface where it is exposed. On the western part of their occurence, this unit exhibits a reefal origin. Further east they have developed within different environ Ment. Nur Hadiyanto et al. ( 2010) suggested that the Paciran was deposited in a ramp-type platform which was much affected by the relative change of sea level. This unit was deposited from Late Miocene to Early Pleistocene

LIDAH FORMATION Lidah FormationThis formation consists of bluish claystone and bedded marl with intercalations of sandstone and lenses of coquina. The lower part of this unit is abundant on Pseudorotalia sp. and Asterorotalia sp as indicator of middle to outer sublittoral environment. This Formation was deposited during Late Pliocene to Middle Pleistocene

GEOLOGICAL HISTORYHumpus Patragas (1995)

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