Bach Long Vi Fm

Period:

Neogene

Age Interval:

Early-Middle Miocene; (6)

Province:
Vietnam Offshore North

Type Locality and Naming

The type section is established on Bach Long Vi Island, Bac Bo Gulf (N = 20°08’; E = 107°43’).

Synonym: Hệ tầng Bạch Long Vĩ: Trần Vãn Tri et al 1977; Trịnh Dánh 1979, 1980, 1985, 1993, (in Vũ Khúc et al.2000); Hoàng Ngọc Kỳ et al. 2001. Hệ tầng Phù Thúy Châu + hệ tầng Họa Mi: PhạnỊ Quang Trung et al. 1999.

Lithology and Thickness

Lacustrine sediments of 175-200 m of grey clayey siltstone, claystone and siltstone interbedded with sandstone.

Lithology Pattern:

Siltstone

Relationships and Distribution

Lower contact

Unconformable on the Phu Thuy Chau Fm.

Upper contact

Not known

Regional extent

Only exposed on the Bach Long Vi island

GeoJSON

null

Fossils

Containing a palynological assemblage characterized by Quercus sp., Castanea sp., Magnolia sp., Ulmus sp., Hamamelis sp., Myrtus sp., Ilex sp., Carya sp., Liquidambar sp.. Containing the following leaf impressions Quercus bonnieri, Qu. neriifolia, Qu. lantenoisi, Fagus antipofii, Litsea magnifica, Persea indica, Sapindus cf. linearyfolius, Phragmites oenlngensis, Quercus neriifolia, Litsea sp. Cinnamomum lanceolatum, Phragmites oeningensis.

Age

Early-Middle Miocene based on correlation with the Tieu Giao Fm and Rinh Chua Fm.

Age Span:

Beginning stage:

Aquitanian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

23.04

Ending stage:

Serravallian

Fraction up in the ending stage:

1.0

Ending date (Ma):

11.63

Depositional setting

It is interpreted as lacustrine in the only exposure.

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).