Geology of Indonesia

This is a brief summary of the geology of Indonesia. The details are stored in Wikibooks [http://en.wikibooks.org/wiki/The_Geology_of_Indonesia]

Tectonics

The tectonics of Indonesia is very complex as it is a meeting point of several tectonic plates. Indonesia is located between two continent plates named the Eurasian (Sunda Shelf) and Australian (Sahul Shelf); and between two oceanic plates called the Indian and Pacific oceanic plates. The Indian oceanic plate subduction beneath the Eurasian continent plate formed the volcanic arc in western Indonesia. This chain of active volcanoes formed Sumatra, Java, Bali and Nusa Tenggara islands. The Pacific and Australian plate movements controlled the tectonic of eastern portion of Indonesia.

Structural Geology

The tectonics processes in Indonesia formed major structures in Indonesia. The most prominent fault in the west of Indonesia is the Semangko Fault, a dextral strike-slip fault along Sumatra Island. The formation of this fault zone is related to the subduction zone in the west of Sumatra.

Palu-Koro fault is another major structural feature formed in the central part of Indonesia. This fault has similar orientation as the Semangko fault, extend from Koro in central part of Sulawesi, to Palu in the west coast of Sulawesi and extend across the Makassar strait to East Kalimantan.

Stratigraphy

The stratigraphy of the western part of Indonesia is relatively young, ranged from Paleogene to Quarternary. The eastern Indonesia has older stratigraphy compare to the western part. The stratigraphy range from Triassic to Tertiary. Devonian limestone were found in Telen River, East Kalimantan, as fragments within Paleogene clastic sediments. Ichthyosaur fossils were found in the mud volcanoes in Kai Island, indicated Mesozoic deposit in the subsurface.

Key Publication and Authors

The geology of Indonesia is very complex and become a place for international research projects. Reinout Willem van Bemmelen is the first geologist who compiled and published a book on the geology of Indonesia in 1949.

Reference List

* Darman, H. & Sidi, H. (eds.), 2000, An Outline of the Geology of Indonesia, Indonesian Geologists Association publication.
* Bemmelen, R. W. van (Reinout Willem van) The Geology of Indonesia The Hague : Govt. Printing Office, 1949. 2 volumes.