SUMARY

Acient shoreline stratigraphy and cross-boundary of depositional systems of the Late Pleistocene - Holocene sedimentary

systems tract in Northern Việt Nam

Trần Nghi, Nguyễn Thị Tuyến , Đinh Xuân Thành, Nguyễn Đình Nguyên,

Trần Thị Thanh Nhàn, Nguyễn Đình Thái, Nguyễn Thị Huyền Trang

Acient shoreline and cross-boundary of depositional systems tracts in late Pleistocene - Holocene related to global sea level fluctuation. In the Northern area of Việt Nam, the relationship between late Pleistocene - Holocene sedimentary facies and sea level change was displayed through the distribution of facies paragenetic sequences at three depositional systems fracts: 1) Lowstand systems tract (LST) is characterized by 4 acient shorelines and a lithofacies paragenetic sequence: deluvial cobble (dr), proluvial gravel (pr), aluvial silty sand (ar) and regressive deltaic clay silty sand (amr LST). This paragenic sequence overlies the errossive surface of late Pleistocene sediment and its early part belongs to Vĩnh Phúc Formation from 50 ka to 20 ka BP; 2) Transgressive systems tract (TST) characterized by 5 acient shorelines and a facies paragenctic sequence elonggated from the sea to the minland including: estuary muddy sand (amt), alluvial silty sand (ambt), coastal marshy sand (at), and trangressive bay greenish clay facics (mt TST). This facies paragenetic sequence constituded a cross-boundary berween 18 ka to 6 ka BP which overlie directly ravenament surface; 3) Highstand systems tract (HST) is characterized by 5 acienrt shorelines and a facies paragenetic sequence including: prodelta clay, delta front sandy mud, deltaic plain muddy sand and modern submainre deltaic facies group. This sequence constituded a cross- boundary to the transgressive systems tracts from 5 ka RP to present.

Người biên tập: PGS.TS. Doãn Đình Lâm.