Ngoc Hien Fm

Period:

Neogene

Age Interval:

early Miocene (N₁¹, nh) (30)

Province:
Vietnam Offshore south

Type Locality and Naming

Malay Basin. The type section is located borehole Ngoc Hien (GK.46-NH-IX), at depths 1750 to 2526 m (N = 7°08’; E = 104°03>). It was named by Đỗ Bạt 2002

Synonym: Hệ tầng Ngoc Hiền: Đỗ Bạt 2002.

Lithology and Thickness

The stratotype is mainly claystone grading upwards into claystone interbedded with sandstone and some brown coal seams. The thickness of the formation in this borehole is 776 m. In general, the Fm is composed mainly of claystone, in some places, greenish-grey, thickbedded limestone, coaly shale, coal seams with thin interbeds of sandstone and siltstone. Limestone usually contains fossils of forams and other marine faunas. Claystone is rich in organic matter, therefore can be gas source rocks. The members of glauconite-bearing sandstone have been determined as good to very good petroleum reservoir beds with the porosity of about 15-30% and the permeability of over 100 mD.

Lithology Pattern:

Claystone

Relationships and Distribution

Lower contact

Unconformably upon the Kim Long Fm

Upper contact

Conformably under the Dam Doi Fm

Regional extent

It is rather largely distributed in the Malaya - Tho Chu Basin.

GeoJSON

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Fossils

Magnastriatites howardi - Echiperiporites estaela Assemblage and the Florschuetzia levipoli Zone of Early Miocene age, Verrucatosporites, Barringtonia, Calamus, FI. trilobata, FI. levipoli, FI. semilobala, Retimonocolpites, Pinus and Rhizophora, some dinoflagellates, and Pediastrum, Acrostichum etc. Nannoplanktons include Discoaster drugii, Heiicosphaera ampliaperta having LAD in NN4 (Early Miocene).

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 marshy, wet delta plain environment with the abundance of coal seams interbedded with littoral and shallow-sea members.

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).