Sam Chom Fm
Period:
Cretaceous
Age Interval:
Middle Cretaceous? (3)
Province:
Sibumasu: Lower Peninsula
Type Locality and Naming
Khao Nam Daeng and Khao Sam Chom, Nakhon Si Thammarat (Raksaskulwong, 1994; Teerarungsigul and others, 1999), where it forms the topographically high rim of the north–south trending syncline running north from Amphoe Bang Khan. Parent unit: Thung Yai Group (Trang Group)
Synonym: หมวดหินสามจอม
[Figure: Geological map of the Thung Yai Gr in Khlong Thom-Bang Khan area, Peninsular Thailand (Meesook, 2011)]
Lithology and Thickness
Mainly matrix-supported conglomerate, conglomeratic sandstone, and thin- to medium-bedded sandstone; clasts are quartz, chert, red sandstone and volcanics.
Thickness: 100 m (Teerarungsigul and others, 1999), 140 m (Raksaskulwong, 1994).
[Figure: Generalized lithological column of the Thung Yai Gr in southern Peninsular Thailand (modified after Teerarungsigul et al. 1999). The upper three formations are Cretaceous while the lowest, the Khlong Min Fm, is Jurassic. Arrows indicate current directions determined from cross-bedding. (Meesook, 2011)]
Lithology Pattern:
Aus conglomerate
Relationships and Distribution
Lower contact
Conformably overlies the Lam Thap Fm
Upper contact
Phun Phin Fm (conformable)
Regional extent
Lower Peninsula: Nakhon Si Thammarat, Surat Thani, Krabi, and Trang provinces.
GeoJSON
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Fossils
Age
Uncertain. If the Thung Yai Gr spans entire Cretaceous, then this formation is middle Cretaceous.
Age Span:
Beginning stage:
Barremian
Fraction up in beginning stage:
0.0
Beginning date (Ma):
130.77
Ending stage:
Albian
Fraction up in the ending stage:
1.0
Ending date (Ma):
100.50
Depositional setting
Alluvial fan
Depositional pattern:
Additional Information
Compiler:
Wen Du - modified from Lexicon of Stratigraphic Names of Thailand of 2013; Assanee Meesook, 2011, Chapter 8 Cretaceous in Ridd, M.F., Barber, A.J., and Grow, M.J., editors, The Geology of Thailand, Geol. Soc. of London.