Dua Fm

Period:

Neogene

Age Interval:

Early Miocene; N₁¹, (31)

Province:
Vietnam Offshore south

Type Locality and Naming

Nam Con Son Basin. The type section is located established in the hole Dua-IX at a depth of 2852 - 3680 m (N = 7°36’; E = 109 °5’).

Synonym: Hệ tầng Dừa: Ngô Thường San 1981; Võ Dương 1982; Lê Văn Cự 1982; Đỗ Bạt 1985, 1993,2000.

Lithology and Thickness

Black claystone, grey siltstone intcrbedded with fine-grained sandstone and lenses of brown coal. In the middle part of the scction sandstone plays the main role with moderate to good sorting, locally containing glauconite, pyrite, with clay and carbonatc cement. Thickness: 828 m.

Lithology Pattern:

Sandy claystone

Relationships and Distribution

Lower contact

Unconformably upon the Cau Fm

Upper contact

Conformably under the Thong - Mang Cau Fm

Regional extent

Nam Con Son Basin.

GeoJSON

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Fossils

Florschuetzia levipoli, Echiperiporites estaela, Helicosphaera ampliaperta, Discoaster druggili; foraminifcra, Miogypsina.

Age

Early Miocene.

Age Span:

Beginning stage:

Aquitanian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

23.04

Ending stage:

Burdigalian

Fraction up in the ending stage:

1.0

Ending date (Ma):

15.99

Depositional setting

It is interpreted as a deltaic environment (fluvial, deltaic plain and delta front) interbedded with shallow-marine environment.

Depositional pattern:

Additional Information

Compiler:

Tran Van Tri and Vu Khuc (Editors; Geology and Earth Resources of Viet Nam, General Dept. of Geology and Minerals of Viet Nam; completed in Dec., 2011), with additional details from Tong-Dzuy Thanh and Vu Khuc (Editors; Stratigraphic Units of Viet Nam, 2^nd edition; 2011; English edited by A. Boucot).