Geology of Singapore

Old Alluvium

Old Alluvium is Late Tertiary (Pliocene) to Mid-Pleistocene Formation described as matrix supported gravelly sand, or poorly cemented sandstone-conglomerate (alluvial fan, fluvial to delta deposits). Formation is interpreted as alluvial fan and proximal braided river facies (Gupta et al. 1987). Deposits were derived mainly from granite rocks. Formation was deposited across Sundaland in a climate which had better defined seasons than currently. Sundaland existed due to dramatic sea-level drop during the Ice Age and included the Malay Peninsula, Borneo, Java and Sumatra. Thus the Old Alluvium is can also be found offshore, mostly to the east of the Bukit Timah Fault.

Literature

Gupta A., Rachman A., Wong Poh Poh Pitts J. 1987. The Old Alluvium of Singapore and the extinct drainage system of the South China Sea. Earth Surface Processes and Landforms 12
Hutchison C.S. 1973. Tectonic Evolution of Sundaland: A Phanerozoic Synthesis, Geological Society of Malaysia, Bulletin
Pitts J. 1984. A survey of engineering geology of Singapore, Geotechnical Engineering, Journal of Southeast Asian Geotechnical Society 15

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