Significance of the foraminiferal assemblage in Holocene
at the borehole KMS-ST01 Sóc Trăng
Ngô Thị Đào, Trân Ngọc Diễn, Nguyễn Thị Thu Cúc,
Nguyễn Tiến Thành, Vũ Ngọc Tuyên, Đinh Văn Phú
The study on the characteristics of the foraminiferal assemblages in Holocene sediments of the borehole KMS-ST01 (distributed in Soc Trang coastal region) aims to evaluate the changes in the environment of Holocene sediments and to contribute to the clarification of the evolutionary history of the study area as well as that of the Mekong Delta region. The 71 species of 37 genera were determinated thanks to the analysis of the 16 samples distributed in the stratigraphic sequences of the borehole KMS- ST01. Based on the changes of the frequency of the two species Ammonia tepida and Rotalidium annectens, there are four assemblages of Foraminifera divided from the lower to uppur part of the borehole. These four foraminiferal assemblages corresponding to the four sedimentary members are the basis for the interpretation of the forming environment of their respective sediments. The sedimentary member no 1 marking the Flandrian transgression in the Mekong Delta area that is characterized by the coastal shallow marine environment. The sedimentery members no 2, 3 and 4 were formed in the regression time and are marked by the changes of the foraminiferal assemblages F2, F3 and F4 respectively.
Keywords: Holocene, Sóc Trăng, foraminifera, Flandrian transgression, Mekong Delta