Chapter 7 Tertiary stratigraphy

摘要: The purpose of this account is to review the complex terminology Tertiary stratigraphic units in Sumatra and propose a revised simplified based on significance formations for tectono-stratigraphic development island. Formations are classified terms Pre-Rift, Horst Graben, Transgressive, Regressive stages. island lies along southwestern margin SE Asian continent (Sundaland) beneath which Indian Ocean Plate currently being subducted at rate about 7 cm -1 Sunda Trench (Fig. 7.1). continental Asia Andean type, with active inactive Quaternary volcanoes rising over 3000 m above Pre-Tertiary basement, exposed towards west coast Barisan Mountains. sedimentary basins occur both SW NE mountains small also within mountain range itself. These described relationship present-day subduction system as forearc, backarc intra-arc or intramontane Mountains transected by Sumatran Fault System, major dextral transcurrent fault zone extends length from Strait Andaman Sea. Stratigraphic research commenced last decades nineteenth century when oil was discovered Telaga Tiga (1883) Said (1885) wells near Pangkalan Brandan North Sumatra. Initially, wildcat drills were sited