Ca Coi Fm

Period:

Paleogene

Age Interval:

Eocene; E₂, (29, 27)

Province:
West Nam Bo, Vietnam Offshore south

Type Locality and Naming

The type section is located at a depth of 1220-2100 m in the CL-1 Borehole, Ca Coi Village, Tra Cu District, Tra Vinh Province (N = 9°33’; E = 106°22’). It was named by

Synonym: Hệ tầng Cà Cỗi: Nguyen Giao 1982; Dỗ Bat 1985, 1993. 2000.

Hệ tầng Cu Lao Dung: Le Van Cu 1982.

Lithology and Thickness

White-grey, violet-reddish, chocolate-colored clastic rocks, such as conglomerate, gritstone, medium- to coarse-grained sandstone containing pebbles and grit, and some claystone. Up to 1 km thick.

Lithology Pattern:

Coarse-grained sandstone

Relationships and Distribution

Lower contact

Unconformably rests upon basement of Jurassic andesite, and andesitic tuffs ( Deo Bao Loc Fm ).

Upper contact

Underlies the Tra Cu Fm of early Oligocene.

Regional extent

West Nam Bo, and Cuu Long Basin (offshore).

GeoJSON

null

Fossils

Pinuspollenites, Pteris, Polypodiaceiosporites, Enica, Gleichenicidites, Podocarpidites, Myricacidites, Triporopollenites, Betuỉaceỉosporítes and Cicatricosisporites, and especially Trũdopoỉỉìs and Plicapollis

Age

Eocene spores and pollen.

Age Span:

Beginning stage:

Ypresian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

56.00

Ending stage:

Priabonian

Fraction up in the ending stage:

1.0

Ending date (Ma):

33.90

Depositional setting

Alluvial and proluvial. It is interpreted as a continental environment (deluvia, proluvia and alluvia) under conditions of high energy of the first stage of subsidence and extension forming the grabens, therefore their distribution area is possibly limited to the slope of some deep troughs of the basin.

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).