SUMMARY
Structure of Pliocene-Quaternary formation in the southwest
subbasin of the Vietnam’s
East Sea and its significance in investigation of ferromanganese nodules and
crust
Nguyễn Văn Vượng, Lê
Duy Bách, Lường Thị Thu Hoài Phạm Nguyễn Hà Vũ,
Nguyễn Đ́nh Nguyên,Phan Thanh
Tùng, Nguyễn Thế Hùng, Hoàng Thị Phương Thảo
Pliocene-Quaternary
formations in the southwest sub-basin of the Vietnam’s East Sea were developed
at the junction of tectonic units including Phan Rang shelf, Tuy Ḥa shear
zone, south of Phú Khánh basin, the thinned crust of SW sub-basin,
differentiated high structures of north Huyền Trân bank and Đá
Lát-Đá Tây reefs, the Măng Cầu high structure and the northern part
of Nam Côn Sơn basin. The thickness of the Pliocene-Quaternary formation
in the study area ranges from 0 to 1.600 m. Based on the characteristics of the
seismic reflection in different profiles, they are divided into 6 areas. Area 1
is filled with horizontal and parallel organic material-bearing clays and
silts. Silty clay mixed with the sand of area 2 developed on the continental
slope. Silty-clay and mud of area 3 were characterized by chevron fold and
strike-slip minor faults. Region 4 is an area of disturbed and disordered silty
clay mixed with carbonate sediment. Region 5 is the abyssal plain featured by
parallel layered of silty-clays. Region 6 is abyssal plain silty-clay and mud
mixed with volcanic materials.
The area of
abyssal plain with parallel bedding sedimentations in the thinned crust of SW sub-basin
has the potential of ferromanganese nodules. The seamounts located at the
depths from -500 to -800 m and in the areas of disturbed, disordered and of
folded sedimentary layers have the potential of ferromanganese crusts.
Keywords: Southwesrtern sub-basin of Vietnam’s East Sea; Tectonics;
Ferromanganese crust, Ferromanganese nodules;Pliocene-Quaternary.