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Ko He Formation

Ko He Fm

Period:

Permian

Age Interval:

mid-Early Permian (4)

Province:
Sibumasu: Upper Peninsula

Type Locality and Naming

The type section, as well as its naming location, is on Ko He ("He Island"; also spelled Ko Hi) in Phuket Province. Proposed by Raksaskulwong and Wongwanich (1993), revised by Chaodumrong and others (2004, 2007), Department of Mineral Resources (2007). The Ko He Formation is considered probably equivalent to the lower pebbly part of the Khao Phra Fm of Piyasin (1975).

Synonym: หมวดหินเกาะเฮ

Lithology and Thickness

Diamictite, sandstone and mudstone. Mainly pebbly rocks or diamictite with subordinate, intercalated mudstone and sandstone. It is poorly sorted, with clasts generally less than 10%, and a matrix consisting of silty mud to muddy sand. Clasts are generally smaller than 2 cm. 120 m thick at the type section.

Lithology Pattern:

Glacial till

Relationships and Distribution

Lower contact

Conformably overlies laminated mudstone thought to be the Spillway Fm at the type section.

Upper contact

Khao Phra Fm (conformable

Regional extent

Upper Peninsula - Phuket Terrane.

GeoJSON

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Fossils

Age

Sakmarian-Artinskian

Age Span:

Beginning stage:

Sakmarian

Fraction up in beginning stage:

0.6

Beginning date (Ma):

292.24

Ending stage:

Artinskian

Fraction up in the ending stage:

0.0

Ending date (Ma):

290.06

Depositional setting

Glaciomarine and debris-flow deposits (Ampaiwan T. et al., 2009). Alternate interpretation had been submarine fan deposits.

Depositional pattern:

Additional Information

Parent unit: Kaeng Krachan Gr.

Compiler:

Wen Du - modified from Katsumi Ueno & Thasinee Charoentitirat, 2011, Chapter5 Carboniferous and Permian in: Ridd, M.F., Barber, A.J., and Grow, M.J., editors, The Geology of Thailand, Geol. Soc. of London; Lexicon of Stratigraphic Names of Thailand of 2013.