GORONTALO BASIN - CELEBES

GORONTALO BASIN - CELEBES

Sulawesi Island is composed by four arms (arm): south arm, north arm, east arm, and southeast arm. In the South Arm there is a large city, Makassar. In North Arm there is Manado, on the East Arm there is Luwuk, and on the Southeast Arm there is Kendari. Kundig (1956) reports that the central part of the Togian is composed of andesite, and east by ofiolite (rock from the oceanic crust and upper mantle of the Earth). Please note that the East Arm of Sulawesi to the south of Togian is composed of ofiolite, the largest ofiolite mass in Indonesia. Because of that Silver et al (1983) once wrote that the Gorontalo Basin is a fore-arc basin with essentially oceanic / ofitic crust. But the mapping by Rusmana et al. (1982) found that the Togian Islands were almost entirely composed of tuffs (petrified volcanic ash) and sedimentary rocks of the Miocene-Pliocene age (between 7-5 million years). In South Sulawesi and West Sulawesi, there are believed to be pre-Tertiary microcontinents that infiltrate, Bone Bay which is very deep and open by the Makassar Strait open, there are also Enigma Bay / Gorontalo Basin, puzzles, and possibly storing microcontinents like in West Sulawesi from Australia.

Gorontalo Basin is located in Gorontalo Province, Central Sulawesi, extending east-west direction, covering an area of ​​34,320 km², at coordinates 120º5 '- 120º50' BT and 0º27 'LU - 1º24' LS. Basement rocks are Cretaceous, with sediment thickness between 500 - 2,000 m at a depth of 2,000 m.

 Location of Gorontalo Basin

This basin is geologically included in the suture basin. This basin is located in the northern region of Sulawesi flanked by the eastern arm of Sulawesi, composed of the East Sulawesi Ofiolite Complex rocks and thebred tertiary sedimentary rocks and the Sulawesi north arm compiled by Tertiary - Quaternary volcanic rocks (Lemigas, 2006).

Basin Type

The beginning of the formation of the Gorontalo basin was due to the fracturing and clockwise rotation of Sulawesi's northern arm in Neogen in about 5 Ma (Hamilton, 1979; Walpersdorf et al. 1997, 1998) or 3.5 Ma (Hinschberger et not active subduction to the southern Sea plate Sulawesi (LLS) (Jezek et al., 1981) is caused by collisions between the Sulawesi east arm arc and the Banggai-Sula micro continent. Another possibility is the opening of the back arc relative to subduction to the south from LLS and the North arm volcanic arc at the end of the Tertiary.

Walpersdorf et al., 1998 and Kadarusman, 2004, assume that the open axis of the Tomini-Gorontalo basin is northeast-southwest, while Hinschberger et al. (2005) in the opposite direction, namely northwest-southeast. The shape of the basin itself has no previous information whether in the form of graben, half-graben or other. Whereas with regard to its geographical position, it is likely that the dominant sediment source originates from the south (Figure 2.2). The Gorontalo Basin was formed due to block-faulting during a trip to the southeast of the East Sulawesi ofiolite complex during the micro-continental collision of Banggai-Sula (Figure 2.3). The basin is quickly filled by Quaternary-Late Late deposits up to 5000m thick (Hamilton, 1979).

Gorontalo Basin Formation Sketch

The main structure of the Gorontalo Basin is east-west, this basin appears in two parts based on bathymetric configuration:

1. To the west of Togan Island (Tomini Bay), it ranges from 1,000 - 2,000 m.
2. To the east of Togan Island, deeper into the Maluku Sea exceeds 3,000 m.

The configuration of this basin structure is generally similar to the Bone Basin, the middle part of which may be filled in the Middle Neogene - Late Neogen until now, in the position of the volcano-magmatic arc basin and the non-volcanic arc basin. Faults may be related to the graben formation that is present off the coast of Poso in the southwest part of Tomini Bay. Comparison of the main depression of the deepest part between Gorontalo and Togan Island is more than 3 s (TWT) above the bedrock acoustics. Indications of the bedrock height structure are only observed in the middle of the basin.

Regional tectonic reconstruction Hall's (2002) shows that the proto-Gorontalo basin is most likely a fore arc basin formed from the Middle Eocene to the Early Miocene, with arcs in the northern arm of Sulawesi.

Evolution of the Basin

The Gorontalo Basin is the result of the collision of the Australian Micro Plate with the Sunda Plate in the Mesozoic. Then followed by the Sunda strain as the Lhasa-Sikuleh Micro Plate which collided with Eurasia. In this period, dispersion of carbonate exposure was dispersed with several intrusions associated with the Oligocene - Middle Miocene volcanic process.

Carbon-Permian (Plate Configuration)

Research at this age is still very little, an explanation of the tectonic framework of Eastern Indonesia in this area is only supported by microplate configurations. Data from previous tectonic orders that are often used are the Southeast Halmahera tectonic model as a Tertiary-derived terrain (Hall, 2002 and Metcalf, 2002 in Jablonski et al., 2007).

Trias-Paleosen (Pre Break-up)

The thickness of the separate plates shows a complicated layer configuration, interpreted as the rest of the previous expansion. These layers are present along the northern boundary of the Gorontalo Basin. Block separation begins 205 jtl and then collides with the Sunda at the age of Cretaceous, then the ofiolite belt is trapped between these two plates. Offiolite exposed on land has been intruded by Granit Toboli aged 96.37 million (Hall, 2002 in Jablonski et al., 2007).

Middle-Eocene Early Eocene (Break-up Phase)

Following the Mangkalihat-Northwest Sulawesi collision with Northeast Sulawesi in the Cretaceous, the Lhasa-Sikeuleh Micro Plate collided with the Eurasian Plate in western Burma-Sumatra at 51.5 million (Rowley, 1996 in Jablonski et al., 2007). This causes a clockwise rotation of the Sundanese Mainland and a number of openings of tear rifts (Longley, 1997 in Jablonski et al., 2007) such as the opening of Bone Bay, opening of Tomini Bay / Gorontalo Basin, Sulawesi Sea subduction. Subduction that tilted towards the continent (roughly westward at that time) occurred many times and produced several magmatic and volcanic periods in western Sulawesi (Satyana, 2014).

During this period, a number of river deposits - deltas developed that could potentially contain hydrocarbons (oil prone). The Gorontalo Basin appears with two sub-basin depositors which are thought to be associated with the expansion of the Sulawesi back in the north and may also have a relationship with the Bone Basin in the south approaching the Palu Fault Zone.

Late Eocene - Upper Miocene

Significant period for Sulawesi, at this time there were collisions, collisions, docking of two Australian microcontinents towards Sulawesi from the southeast (Buton-Tukangbesi microcontinent) and from the east (Banggai-Sula microcontinent). In this period it is estimated that the main direction / polarity of the Sulawesi arcs for both magmatic arcs and subduction pathways from the convex to the ocean becomes concave towards the ocean (to the east at this time). The reversal of the polarity of the Sulawesi arcs is frontally due to the collision of the Banggai-Sula microcontinent which strikes it at the central point of Sulawesi, in the center, at the pivot point. The form of Sulawesi "K" is estimated to occur at this time. Sulawesi flips from convex to east to concave to the east. The reversal of the Sulawesi arcs occurs through the mass transfer of the Earth's crust called "rotation", the Southeast Arm rotates counterclockwise so that it opens to expand the Bone Bay to the west, the North Arm rotates clockwise so that it closes the Gorontalo Basin (Satyana, 2014).

 

Scheme of formation of "K" on Sulawesi Island

Upper Miocene - Resen

The finalization period for Sulawesi arc arcs and tectonic escape periods in Sulawesi. As theorized, following collisions, there will be a post-collision tectonic escape, then after the clash of Buton-Tukangbesi and the clash of Banggai-Sula, there was a tectonic escape in the form of large horizontal faults that fractured and shifted Sulawesi. These faults are generally eastward, namely towards the free oceanic edge at that time as tectonic escape theory. The faults in the landscape of Palu-Koro, Matano, Lawanopo, Kolaka, and Balantak occur through the mechanism of post-collision tectonic escape. Tectonic escape is also manifested in the form of cracks opening, extensional, in the collision area of ​​Banggai-Sula or Buton-Tukangbesi.

 

Post-docking tectonic model from Sulawesi

Basin Stratigraphy

Regional Stratigraphy

Based on the sheet geological map of Tilamuta (S. Bachri, et al., 1993) and the Kotamobagu sheet (T. Apandi, et al., 1997) from the Bandung Geological Research and Development Center, the basin stratigraphy is composed of rock formations as follows:

a. Surface Deposition

• Alwium (Qal), consisting of: loose sand, clay, silt, mud, gravel and gravel. These rock units occupy lowland areas, especially in the plains, river valleys and swamps. Disposal of these rock units is limited to watersheds (DAS) such as those located west of Lake Limboto.
• Lake sediments (Qpl), consisting of: clay stone, sandstone, and gravel. These rock units are generally dominated by clay stones that are brownish gray in color, locally contain plant residues and lignite, in some places there are fine grained to coarse sandstone, and gravel. Locally there are small-scale cross-sectional structures in the sandstones. Generally these rock units are still incompressible and are estimated to be Pliocene to Holocene. This distribution of rock units occupies the valley around Lake Limboto. The thickness of this rock unit reaches 94 meters and is lined by Diorite rocks (Trail, 1974).

b. Sediment and Volcanic Rock Unit

• Anombo Formation (Teot), consisting of: basal lava, andesite lava, volcanic breccia, with intermittent wake sandstones, green sandstones, siltstone, red limestone, gray limestone, and few thermal rocks. The age of these rock units is estimated to be Eocene to the Early Miocene. The rock units of this formation are found in the area around G. Tahupo (828 m) to the south.
• Dolokapa Formation (fmd), consisting of: wake sandstones, siltstone, mudstone, conglomerates, tuffs, tuff lapilli, agglomerates, volcanic breccia and andesitic lava to basalt. The age of this formation is estimated to be Middle Miocene to Early. Late Miocene with an "inner sublitoral" depositional environment with an estimated thickness of more than 2,000 meters. The distribution of rock units in this area occupies the central and northern parts of the Gorontalo region, namely to the north of the Limboto Basin (Paleleh area to around the Kuandang area).
• Bilungala Volcanic rocks (TMBV), consisting of: volcanic breccias, tuffs and lava. these rock units are thought to be Middle Miocene to the late Late Miocene with a thickness of more than 1,000 meters. The distribution of these rock units is in the eastern part of the Gorontalo region, in the Tolotio area to the east.
• Wobudu Breccia Unit (Tpwv), consisting of: volcanic breccias, agglomerates, tuffs, tuff lapilli, andesite lava and basal lava. This rock unit is thought to be of the Early Pliocene age with an estimated thickness of 1,000 to 1,500 meters. This rock unit is exposed in the northern part of the Limboto Basin, starting from the Paleleh Mountains to the west of Kuandang Bay.
• Pinogu Volcanic rocks (TQpv), consisting of: the intersection of agglomerates, tuffs and lava. This rock unit is estimated to be of Late Pliocene to Early Pliocene with a thickness of up to 250 meters, while its distribution is in the south of the Limboto Basin and the Teluk Kuandang area and in several places that form separate hills.
• Klastik limestone (TQI), consisting of: calcarenite, calcirudif and coral limestone. This rock unit is thought to be of Late Pliocene to Early Pliocene with a thickness of between 100 and 200 meters, while its distribution is in the west of Lake Limboto.
• Reef Limestone (QI), consisting of: coral limestone. The age of these rock units is estimated to be Late Pliocene until the Holocene reaches a thickness of 100 meters, while its distribution is in the area near the Limboto lake and the eastern coast of the east.

c. Breakthrough Rock Unit

• Diorite Bone (TMB), consisting of: diorite, quartz diorite, granodiorite and adamelit. These rock units are thought to be Middle Miocene to the early Late Miocene (Trail, 1974), and are found in the eastern part of the Gorontalo fault, also in the west of the fault in the north of the Limboto Basin (near Kuandang and Paleleh).
• Boliohuto diorite (Tmbo), consisting of: diorite and granodiorite These rock units are thought to be Middle Miocene to Late Miocene, and have a distribution in the area of ​​G. Boiiohuto.
• Rock Return Unit, consisting of: Andesite (Ta) and Basal (fb). These rock units break through rock units from the Tinombo Formation, Dolokapa, and Wobudu breccia, so that they are generally considered Miocene to Pliocene.

Reference:

• Jablonski, D., Priyono, P., Westlake, S., Larsen, O. A., 2007, Geology and Exploration Potential of the Gorontalo Basin, Central Indonesia-Eastern Extension of the North Makassar Basin?, Indonesian Pet. Assoc., 31st Annual Convention Proceeding.
• Puspita, S. D., Hall, R., Elders, C. F., 2005, Structural Styles of the Offshore West Sulawesi Fold Belt, North Makassar Straits, Indonesia, Indonesian Pet. Assoc., 30th Annual Convention Proceeding.
• Rangin, C., Silver E. A., 1990, Geological Setting of the Celebes and Sulu Seas, Proceedings of the Ocean Drilling Program, Initial Reports, Vol. 124.
• Silver, E. A., McCffrey, R., 1993, Ophiolit Emplacement by Collision Between the Sula Platform and the Sulawesi Island Arc, Indonesia, Journal of Geophysical Research, vol. 88, No. B11.
• http://awangsatyana.blogspot.com/2013/11/cekungan-gorontalo-teluk-tomini.html

ASEM-ASEM BASIN, SOUTH KALIMANTAN

ASEM-ASEM BASIN, SOUTH KALIMANTAN

Asem-asem Basin is one of the Tertiary basins in Indonesia which has considerable energy potential, such as oil and gas and coal. The Asem-Asem Basin is located southeast of the Sundaland Continent Crust and is separated from the Barito Basin by the Meratus Mountains in the West. The Asem-Asem Basin is located in the southeastern part of the Sundaland continental plate boundary. This basin is separated from the Barito Basin by the Meratus Mountain in the west.

 

Map of Location of the Asem-Asem Basin (Rasoul Sorkhobi, 2012)

The Asem-Asem Basin is located in South Kalimantan and to the east of the wing of the Meratus Mountains. The eastern wing whose territory covers offshore areas is estimated to have Upper Oligocene limestones to the Lower Miocene, especially above the basement. To the north, this basin is separated from the Kutai Basin by the existence of Adang Flexure or fault that separates Barito from Kutai. To the south, extends towards the Java Sea to the height of Florence. This basin is asymmetrical with the front in the frontal zone of the Meratus Mountains and exposure to the Sundaland palace.

 

Regional geological map of Kalimantan

 

Physiography

Kalimantan Island is generally a swamp and fluvial region. In addition there are also flat and mountainous regions scattered on this island. The plains are scattered on the edges of the island and most of the mountains are in the center of the island. In the northern part of Kalimantan Island is the Pegungungan Kinibalu zone and in the North-West there are a range of Muller Mountains and the Schwaner Mountains. In the southern part there is the Meratus Mountains.

Physiography of Borneo Island, without scale (Bachtiar, 2005).

Van Bemmelen (1949) divided the western part of Kalimantan Island into two parts, namely:

• Kapuas Atas Mountains, located between the Rejang Valley in the north, Upper Kapuas Basin and Batang Lupar Valley in the south.
• Madi Plateu, located between the Upper Kapuas Basin and Melawi River.

Whereas in the eastern part of Kalimantan, Van Bemmelen (1949) also divided this area into two parts, namely:

• A series of mountains in northern Kalimantan, ending in the Darvel Bay Peninsula.
• Other mountain ranges, ending on the Mangkalihat Peninsula.

On the island of South Kalimantan itself has several large rivers, including the Kapuas River, the Barito River, the Negara River and the Kahayan River. The Barito River is the second largest river on the island of Borneo. The Barito River originates in the Muller Mountains and produces the Barito Basin which is bordered by the Meratus Mountains in the east. The rivers in the area of ​​South Kalimantan originate in the central part of the island of Borneo, namely the Schwaner Mountains and also the Muller Mountains. The Schwaner and Muller Mountains have a height between 200-2000 meters above sea level. While the direction of the rivers is relatively north-south and empties into the Java Sea. These rivers flow at an altitude of 0-200 meters above sea level. These large rivers occupy a large part of the southern part of the island of Borneo. In the eastern part of the Province of South Kalimantan there is the Meratus Complex Mountains which is a trace of subduction activities at the age of Cretaceous (Rotinsulu et al., 2006).

Stratigraphy

The basins in South Kalimantan are the Barito Basin and the Asem-Asem Basin which generally have relatively similar stratigraphic features from the old to the young. The Barito Basin and the Asem-Asem Basin are separated by the Meratus Mountains. In the north it borders the Kutai Basin which is separated by Andang Fault. Whereas the western part is limited by the Sunda Exposure. At first the Barito Basin and the Asem-Asem Basin were the same basin, until the Early Miocene there was the removal of the Meratus Mountains which caused the separation of the two basins (Satyana, 1995).

The stratigraphy of the South Kalimantan area includes several formations, namely basements in the form of Malihan Rock, Tanjung Formation, Berai Formation, Warukin Formation, and Dahor Formation and Alluvial Deposits. These formations are Eocene to Pliocene.

Basement rocks in the form of high levels of metamorphic rocks consisting of low-level amphibolite schist and composed of filite. Sikumbang (1986) introduces this high level metamorphic rock as Sekis Hauran which is composed of green schist containing quartz, muscovite, biotite, hornblende, epidote and low level minerals as Filit Pelaihari which consists of filite containing chlorite and mica minerals on the surface plane shiny and batusabak. This gray rock has a Jura age.

The Tanjung Formation was first introduced by Pertamina (1980; in Supriatna et al., 1981) for the oldest Tertiary rock formations in the Tanjung oil field. The Tanjung Formation is composed of alternating coarse sandstones, conglomerate sandstones and conglomerates at the bottom, gray claystone in the middle and thin siltstone silt and fine sandstone at the top that has a river or fluvial depositional environment and Late Eocene (Martini, 1971). At the top of this formation there is carbonate rock which is the beginning of the formation of the Berai Formation.

The Berai Formation is deposited in harmony above the Tanjung Formation, but in some parts there is a relationship that indicates an inconsistency. But in general this formation is deposited in harmony above the Tanjung Formation. The Berai Formation, which is dominated by limestones, has a deposition environment of the front reef, perhaps between the back, sublitoral, relatively shallow reefs, perhaps less than 30 meters, in the form of shallow sea or lagoon which is late Oligocene - Early Miocene (Te1-5 Adams, 1970).

The Warukin Formation was first used by Pertamina (1980; in Supriatna et al., 1981) and the location of its type is in the Kambilin area, Balikpapan, East Kalimantan. In harmony the Warukin Formation is deposited on the Berai Formation which is composed of gray-colored claystone, sandstone and coal inserts. The lower part of this rock sequence consists of the dominance of gray to blackish claystone with the insertion of medium-sandstone sandstones with parallel laminated sedimentary structures from carbon material, flaser and burrow. This formation is deposited in the marsh and tidal depositional environments of the Early Miocene-Late Miocene age.

The Dahor Formation is deposited incongruously above the Warukin Formation. The Dahor Formation is composed of claystone to sandstone clay, coarse sandstones - conglomerates that have gradual bedding structures, reddish sandstone with parallel laminated sedimentary structures and crossings and conglomerates that have components of granite, malihan, sediment and volcanic size 5-15 cm.

The Dahor Formation has a delta deposition environment and is Plio-Plistocene. Alluvial deposits in the Asem-Asem Basin are the result of a river (fluviatil) process which consists of deposits of mud, sand, gravel, greasy and lumps that are of the Quaternary age.

 

Regional regional stratigraphy of Asem-asem

Geological Structure

The geological structure found in South Kalimantan is anticline, syncline, upward fault, horizontal fault, and fault fault. The fold axis is generally northeast-southwest direction and is generally parallel to the normal direction of fault. In South Kalimantan there are two large basins, namely the Barito Basin and the Asem-Asem Basin. These two basins are bordered by the Meratus Mountains which cross from the north-southwest. The Barito Basin and the Kutai Basin are separated by an east-west fault in the northern part of South Kalimantan Province, this fault is known as Adang Fault (Mudjiono and Pireno, 2006).

 

Regional geological structure of the Asem-asem Basin

The structural regime that occurs in the Barito Basin is the transpression and transmission regime. The structure found is a fold that traverses northeast-south southwest (NNE-SSW) in the northern part of the basin. While in the Meratus Mountains there are faults carrying basements. These faults are marked by the presence of drag or fault bend fold and fault fault. Whereas the folds in the Meratus Mountains, which are in the northern part of the mountain, are trending north-south-southwest (NNE-SSW) and those in the south are north-south. Many folds are found in the form of anticlines and some synclines. There are many upward faults in the Meratus Mountains region with a general north-east-southwest direction (NNE-SSW). Horizontal faults are also found in the Meratus Mountains, generally not too long, in contrast to the rise faults that have a continuous continuity. Horizontal faults are generally in the form of faults trending and trending northwest-southeast (Satyana, 2000).

The study of geophysical data shows that the Meratus - Samarinda anticlinorium is estimated to have a general north-directed axis slope and is indicated regionally based on rock moves that the fault zone can generally be divided into three blocks, namely north, middle and south blocks. The northern block has been lifted on the western wing of the anticlinorium along the northern fault zone and is called the Tanjung fault zone. The middle block is located between the Tanjung fault zone and the Klumpang fault zone which is characterized by the emergence of granitic and ultrabasic breakthrough rocks along the fault zone. While the southern block is characterized by the extent of the development of the northeast trending fault which is closely related to the breakthrough diorite and ultramafic rock complex. A number of faults are southeast-northwest trending which are associated with magnetite deposits in the Pleihari region and can be observed from the emergence of a fault system intersection of all the blocks above.

Reference:

• Heryanto, R., 2010. Geologi Cekungan Barito. Bandung: Badan Geologi Kementrian Energi Sumber Daya Mineral.
• Muhammad Hidayat  Et Al, 2015,  Kondisi Dan Sumber Daya Geologi Pada Cekungan Asem-Asem, Provinsi Kalimantan Selatan, Jurusan Teknik Geologi,Sekolah Tinggi Teknologi Nasional, Yogyakarta
• http://suarageologi.blogspot.co.id/2012/06/stratigrafi-cekungan-asem-asem_14.html
• http://rorygeobumi.blogspot.co.id/2012/04/fisiografi-kalimantan.html
• http://rorygeobumi.blogspot.co.id/2012/04/kerangka-tektonik-regional-kalimantan.html

 

The Akimeugah Basin - Papua

The Akimeugah Basin - Papua

The Akimeugah Basin is located north of the southern Papuan basement high (Merauke Ridge) which separates it from the Arafura Basin to the south. This basin Judging from its association with surrounding basins, the akimeugah basin is associated with basins that have produced hydro-coal in the West Papua Basin and Australian basins. From tracing various journals and articles, the geochemical literature will provide an overview of the active host rocks in the area.

 

The index map of the Akimeugah and Sahul Basin is based on the Indonesian Sediment Basin Map (Badan Geologi, 2009).

The Akimeugah Basin begins as a passive margin, which is a basin formed by rifting on the northern edge of the Australian continent at the edge of this bank, experiencing cracking due to the part of the northern part of the mass that wants to escape and move from Australia. In this crack a horst and graben are formed which in the graben is deposited sediment of Paleozoic and Mesozoic synrifting. Then, when this part is separated and away from Australia (drifting) sediment drifting is deposited which is generally in the form of shale or limestone, this event occurs until Paleogene.

 

Tectonic maps and cross sections of the foreland basin

Cross section of the foreland basin in eastern Indonesia

At the age of Neogen, Akimeugah collided with the Central Range of Papua (Back of Papua). Since then the type of foreland basin Akimeugah. Passive margin of the Paleozoic-Neogene is bent into the lower Banda route and Central Range. Then at the front of the buckling (foredeep) deposited molassic sediments which are erosional products from nearby heights. However, and burial by the sedimentary molasses part of the passive margin, Akimeugah has ripened Paleozoic, Mesozoic, or Paleogene host rock in the graben then the hydrocarbon migration will move flips from foredeep to the forebulge (the direction in the direction of the passive margin that is not bent like foredeep) laterally, or moves vertically towards the immobilization deformation zone in the impact area. The main controls of the Akimeugah basin are rifting and drifting in the Mesozoic-Paleogene Paleozoicum, and collisions on Neogene (Awang Satyana, in Sabarnas Agus 2011)

  

Stratigraphy of the Akimeugah Basin

The Akimeugah Basin consists of pre-cambrian-tertiary deposits. The basic rock consists of Gabro rocks aged pre-cambrian and Metamorphic rocks. Followed by the deposition of the Permian Dolomite Modio formation and the Aiduna Formation which were deposited incongruously. Then it was harmoniously deposited on top of Mesozoic clastic formations (Tipuma, Kopai, Woniwogi, Piniya and Ekmai Formations), and some carbonate coatings locally. Above the Ekmai Formation, overlaid by clastic and limestone Paleocene-Miocene age (Waripi, Lower Yawee, Adi Members, and Upper Yawee) are out of tune. The last deposition was the final claystone clay from the late Miocene to Plio-Pleistocene and the uncoated local carbonate, the Buru Formation.

The petroleum system that works in the Akimeugah Basin is in the Kozelang Group, which is Mesozoic. The auction group consists of four formations, namely: Kopai Formation, Woniwogi Formation, Piniya Formation, and Ekmai Formation. The Kopai Formation is source rock with kerogen types II and III, Ro is greater than 0.6%, and TOC ranges from 1 - 10% on Sahul Exposure. The Woniwogi Formation is a reservoir rock with porosity ranging from 12-14% with permeability between 200 - 500 mD (Meizarwin, 2003). The Piniya Formation is a covering rock composed of claystone with a thickness of up to 900 meters (Panggabean and Hakim, 1986). The Ekmai Formation is a reservoir rock in the Bayu - Undan Field, but in the Akimeugah Basin this rock is not a good reservoir rock.

Australia and Papua New Guinea have produced oil and gas from the same basin system, namely the foreland basin, the same reservoir rock, which is the Middle Jurassic - Cretaceous sandstone, and may conclude the same petroleum system. Indonesia's declining oil and gas reserves are a shared responsibility, moreover geologists are the key to finding that potential. With new concepts, more complete data, and a deeper interpretation of existing data, the potential for oil and gas reserves in the Akimeugah Basin can be found. The hope of oil and gas is in the East of Indonesia, precisely in the Akimeugah Basin of Papua Island.

Reference:

• Satyana, A.H. (2013) : Exploring & producing Petroleum in Eastern Indonesia: Update knowledge & Recent Trends. Guest Lecture Ikatan Alumni Teknik Geofisika ITB.
• Satyana, A.H., Damayanti, S., Armandita, C. (2012) : Tectonics, Stratigraphy, and Geochemistry of The Makassar Straits: Recent Updates from Exploring Offshore West Sulawesi, Opportunities and Risks. Proceedings Indonesian Petroleum Association 36th Annual Convention.
• Satyana, A.H., Damayanti, S., Armandita, C. (2012) : Tectonics, Stratigraphy, and Geochemistry of The Makassar Straits: Recent Updates from Exploring Offshore West Sulawesi, Opportunities and Risks. Proceedings Indonesian Petroleum Association 36th Annual Convention.
• Situmorang, B. (1982) : The Formation of The Makassar Basin as Determined from Subsidence Curves. Proceedings Indonesian Petroleum Association 11th Annual Convention, 83-107.
• https://dzulfadlib.wordpress.com/tag/lapangan-minyak/
• http://geomagz.geologi.esdm.go.id/cekungan-akimeugah-dan-sahul-harapan-baru-penemuan-migas/