Bulletin of the Geological Society of Malaysia, Volume 6, Jul, 1973, pp. 257 – 271
1Billiton International Metals B.V., The Hague, Netherlands
2International Institute for Aerial Survey and Earth Sciences (L.T.C), Enschede, Netherlands
3Formerly Billiton N.V., The Hague, Netherlands
Abstract: An acoustic continuous profiler survey over extensive sea areas between Singkep and Bangka and around the Karimata Islands, supplemented by sea drillings, indicates the following sedimentary succession: below the sea, the basement, which on the islands consist of folded sediments and granitic rocks, is covered by unconsolidated sub-horizontal, mostly sandy sediments with intercalated peat layers near the top, probably of Tertiary age. Next a sequence of sediment-filled gullies incised into the older sediments and sometimes also into the basement is present. Again, peat layers are of common occurrence, indicating a terrestrial origin for most of these sediments; at least part of these deposits seems to be of young Tertiary age.
An extensive, nearly horizontal planation surface is found at depths of 20-30 m below sea level. This surface is at remarkably constant depth and very flat, indicating a marine origin. Spotty red clay is present on part of this surface, indicating a temporary emergence of the abraded surface.
A young sedimentary deposit, mainly of marine origin, represents the latest postglacial transgression. Part of its material is derived from the surrounding islands.