Tra Cu Fm

Period:

Paleogene

Age Interval:

Early Oligoene; E₃¹, (29, 27)

Province:
West Nam Bo, Vietnam Offshore south

Type Locality and Naming

The type section is established on the basis of materials from the CL-1 Borehole, Ca Coi Village, Tra Cu District, Tra Vinh Province, at a depth of 1082-1220 m (N = 9°33’; E = 106°22’).

Synonym: Hệ tầng Trà Củ: Nguyễn Giao 1982; Lê Văn Cự 1982; Ngô Thường San 1988.

ĐiệpTrà Cú: (part.): Đỗ Bạt 1985, 1993.

Lithology and Thickness

Sandstone, gritstone with clayey siltstone containing pebbles, gravel and sand. The pebble and grit grains are of different lithological composition, mainly andesite and granite. The formation thickness in the CL-1 Borehole is 138 m.

Lithology Pattern:

Coarse-grained sandstone

Relationships and Distribution

Lower contact

Unconformably upon the Ca Coi Fm, or upon the basement complex.

Upper contact

Underlies the Tra Tan Fm

Regional extent

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

GeoJSON

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Fossils

Oculopollis - Magnastriatites howardi Assemblage. It includes mainly Magnastriatites howardi, Verrucatosporites, Triletes, Pinuspoỉlenites, Oculopollis of Eoccne-Oligoccnc age based on Oculopollis and Magnaslriatites howardi.

Age

Lower Oligocene.

Age Span:

Beginning stage:

Rupelian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

33.90

Ending stage:

Rupelian

Fraction up in the ending stage:

0.7

Ending date (Ma):

29.27

Depositional setting

It is interpreted as a deluvial, proluvial, alluvial, fluvial to lacustrine and lagoonal situations.

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).