Structural development of the Ombilin Basin West Sumatra

Contrasting tectonic styles in the Neogene orogenic belts of Indonesia

“…In the Palaeogene the region was affected by extension and subsidence, resulting in the formation of rift basins. Some of these basins, such as the coal-bearing Ombilin Basin of West Sumatra, lie within the Barisan Fault System and have been interpreted as pull-apart basins formed by transtensional movements along the fault (Koesoemadinata et a/.1978;Koning & Aulia 1985;Wang et al 1989;Situmorang et al 1991). Continuation of movements along the fault led to the opening of the Andaman Sea (Curray et al 1979;Harding 1983 at University of St Andrews on May 15, 2015 http://sp.lyellcollection.org/ Downloaded from structure, leading to the erosion of the cover and exposure of the basement rocks which now rise to nearly 4000 m above sea level.…”

Paleoenvironmental conditions in the late Paleogene, Sumatra, Indonesia

“…The Sitangkai and Silungkang faults define the northern and southern boundaries of the basin, respectively (Koning, 1985;Situmorang et al, 1991). The Sumatran Fault System resulted from the oblique subduction of the Indo-Australian plate under the Eurasian plate (Situmorang et al, 1991). Tensional tectonics that resulted from the strike-slip movement of this collision produced the graben-like, pull-apart structure of the Ombilin Basin (Koning, 1985;Fatimah and Ward, 2009).…”

“…The exposed segment of the basin is about 25-km wide and 60-km long, trends NW-SE and roughly parallels the Sumatran Fault System. The Sitangkai and Silungkang faults define the northern and southern boundaries of the basin, respectively (Koning, 1985;Situmorang et al, 1991). The Sumatran Fault System resulted from the oblique subduction of the Indo-Australian plate under the Eurasian plate (Situmorang et al, 1991).…”

Geological Structure Analysis to Determine the Direction of the Main Stress at Western Part of Kolok Mudik, Barangin District, Sawahlunto, West Sumatera

“…Overall the strucuture of the basin ombilin showed transtensional duplex or pull apart duplex systems. Woodcock and Fischer (1986) said in Situmorang, et.,al (1991). subduction of geometry from duplex faults would be meet in sub basin became single shear zone.…”