geological characteristics of the Phúc Tần Bank in the
Phan Đức Tuấn, Vũ Bá Dũng, Nguyễn Văn Cử
The processing and geological interpretation of 16 shallow seismic high-resolution profiles with 350 km-line show that: a/ Complicated Miocene-Quaternary geological structure of the Phúc Tần Bank with polycompositional basement: pre-late Miocene intrusives, Middle Miocene basalt, upper Miocene terrigenous beds and basalt; b/ Atoll formed on Upper Miocene basalt basement thanks to the development of corals and other organisms and their mechanical weathering products from Pliocene to Holocene during six rise-fall cycles of sea level; c/ Upper Miocene-Holocene stratigraphic column can be divided into seven sequences. Most of sequences have three system tract: trangressive system tract, highstand system tract and regressive system tract. Coral gravel-pebble bed which is exposed on the sea floor or covered by thin layer of Quaternary sediments 7-10 m in thickness and lies between the weathering surface R4 and Pliocene basalt-terrigenous, is important for the correlation of Pliocene-Quaternary stratigraphy and for the prospection of solid mineral resources.
The study area can be divided into four small structures: Central coral zone, SE uplift zone, SW subsided zone and NW Quaternary activated zone.
Người biên tập: TS. Trần Tuấn Dũng