Sarmi Regency is located in Papua Province, West Papua Indonesia. The geology of the Sarmi Regency area is generally divided into three main formations, namely mountain formations, valley formations and alluvial plain formations. Cendrawasih University reports that mountain formation is influenced by the Jayawijaya Mountains and Gautier Mountains, while valley formation is influenced by the median depression of the coastal plain, especially in the Tariku/Taritu valley. The alluvial plain formation is the largest formation covering the depressions of the Rouffaer and Jayawijaya mountain ranges which are washed away by river water to the coastal area.

This formation was formed from the development of the earth’s crust which moved north to form the Mamberamo Container Fault and changed location to the Gautier Fault. The Sungkup Fault line extends to the south and consists of the Anjak Fault and Shear Fault, thereby faulting the Plio-Pleistocene rocks of the Mamberamo Formation and the rocks of the Pacific crust below. Along the containment fault route, intrusions of shale and mud rock fragments are found, generally consisting of sedimented clay and unsorted rock components with coarse fragment size faults. Now these pieces of mud are still active and form river terraces which are often found in this area.

Geological Formation:

1. Alluvium, Area (Ha): 1,587,953.12, Percentage (%): 46.81

2. Poton / Mud Vulcano Fields area, Area (Ha): 116,266.20, Percentage (%): 3.43

3. Diapir, Mudstone displaced by boulders, Area (Ha): 294,457.16, Percentage (%): 8.68

4. Basallah to ansitan lava, generally changes, Area (Ha): 102,936.63, Percentage (%): 3.03

5. Siltstone marl, limestone, grewake, contains plankton at the base and lignite at the top, Area (Ha): 1,264,669.31, Percentage (%): 37.28

6. Limestone sediments and lime glacial sediments, Area (Ha): 4.39, Percentage (%): 0.0001

7. Serpentinite, perodotite, priroxenite and Gabbro, Area (Ha): 14,134.06, Percentage (%): 0.42

*Source Papua Province Mining Service

The Alluvium Rock Formation resembles a median depression which is characteristic of coastal areas. This rock is a marine neogen sedimentary rock covered by an alluvial layer and very weakly folded. This formation spreads along the coast from Lower Mamberamo, Sarmi, Bonggo, a bit of the West Coast and along the south side from Upper Mamberamo to the East Coast. In the lower part of this formation it consists of gowake rock and marl, breccia, volcanic, coglomerate and dolomite inserts, while in the upper part it consists of layers of conglomerate rock, sandstone, dust rock, coal inserts and slate limestone.

Marl and silt rock formations are depressions in the Rouffaer mountain range and the Mamberamo Valley. This area is located in the central part of the Sarmi Regency area extending from West to East flanked by alluvium formations. The lithology of this formation shows that the lower part consists of limestone, growake and contains plankton and at the top there is lignite. Part of this formation area is now covered by swamps around the Bonggo and Upper Mamberamo areas.

Diapir formations, mudstones rubbed together with boulders, are formations resulting from evolution since the Pratertiary era with sediments and igneous rock intrusions. These rocks experienced uplift at the end of the Palogene and finally uplift occurred in the late Neocene. At that time, intrusion of plutonic rocks such as menzoite, porphyritic and porphyritic diorite occurred. These rocks are like chunky mudstone. This formation spreads in the central part of the Sarmi area, Upper Tor, West Coast and Central Mamberamo.

Two other rock formations, namely the poton/mud volcano fields found in Central Mamberamo and Bonggo and basalt lava and up to andesite which generally change, are found in Upper Tor.

The Dabra area (Upper Mamberamo) has steep topography which is a transitional area of lowland and highland geological formations. This region is representative of the northern part of the eosin island arc complex with sequential bands from North to South.

The Geological Formation of the Sarmi Region described above shows that this region has the potential to mine metal minerals and hydrocarbons. Based on the map of the distribution of metal and hydrocarbon minerals in Papua Province issued by the Department of Mines and Energy, the Sarmi area is found to have minerals from minerals such as copper (Cu), lead (Pb), iron (Fe) and chromium (Cr). . The hydrocarbon mining materials that are thought to be found in this area are oil and natural gas.

The potential for copper and lead metal mining materials is found in the upper Mamberamo District in the eastern part between Tayai Village and the northern part of Fokri. It is suspected that this metal mining material is part of the seed mountain deposits (Ertberg) which consist of husk with a tooth-like shape towards the outside surrounded by lime silicate and then diorite. The main copper minerals found in this area are bosite and a little chalcopyrite with the accompanying minerals idaite, chalcocite, covellite, galena, pyrite, sphalerite, pyrargite and marcasite.

Another potential metal mineral mining material found in Sarmi Regency is Iron Sand. This iron sand is found along the Sarmi District Beach. This metal mineral consists of iron (Fe) and Crom (cr).

The potential for hydrocarbon mining materials in the Sarmi area is in the form of oil and natural gas. There are two main basin areas that are thought to contain oil and natural gas, namely the northern offshore area of Sarmi Regency and the Upper Mamberamo District area. The oil and gas basin off the north coast of Sarmi Regency is a basin with discoveries of producing oil and natural gas, while the basin in Hulu Mamberamo District is an oil and natural gas basin that has been drilled but has not yet been discovered. Apart from these two areas there are also several dry wells in Central Mamberamo District and West Coast District. Dry wells in the Central Mamberamo District are located to the west, while in the West Coast District they are located on the Biri River and on the Beach. There are also natural gas wells off the coast of the Hulu Mamberamo District.

Based on the geological structure of the Sarmi region, it appears that most of the natural gas basins are located along the Mamberamo watershed, the regional structure of which is the Sungkup Fault line with crustal development moving northward to form the Mamberamo Sungkup Fault. The Mamberamo containment fault consists of factoring faults and strike-slip faults, thereby intersecting Plio-Pleistocene rocks with the Pacific crust rocks beneath them. This geological structure allows the formation of basins which are thought to contain oil and natural gas.