Mau Son Fm
Type Locality and Naming
The type section is located on the dirt road from Na Bo to Khuoi Hai villages (N= 21°36’; E 107°04’). It was named by Jamoida A.I., Pham Van Quang 1965
Synonym: Hệ tầng Mầu Sơn: Jamoida A.Ĩ., Phạm Văn Quang (in Dovjikov A.E. et al. 1965); Vũ Khức (in Vũ Khúc et al.1965, 2000), Nguyễn Kinh Quốc (in Vũ Khúc, Bùi Phú Mỹ et al. 1990); Vũ Khúc, Trịnh Thọ (in Trần VănTrị et al. 1977 -Diệp); Vù Khúc - Điệp 1980,1984 - Điệp, 1986 - Điộp (in Vũ Khúc et al. 1986). Terrains rouges in é rieurs (part.): Pattc E. 1927; Saurin E. 1956 (Trias). Diệp Giao Li ém: Phạm Văn Quang 1973.
Lithology and Thickness
Continental red beds of sandstone and claystone: Charactistic section on north side of Mau Son Range is 1430 m: (1) Grey, medium- to coarse-grained sandstone, locally bearing quartz pebbles, interbedded with yellowish and chocolate claystone and lenses of marl; 600-800 m thick. (2) Light chocolate claystone and siltstone, dark grey to grccnish-grcy clayey shale with interbeds of fine-grained sandstone and lenses of light grey marl, 500-700 m thick. Beds of conglomerate and sandstone in the upper part of the previous stratotype are now assigned to the overlying Jurassic Ha Coi Fm.
Relationships and Distribution
Lower contact
Conformably upon the Na Khuat Fm.
Upper contact
Unconformably covered by the Norian-Rhaetian Van Lang Fm. Beds of conglomerate and sandstone in the upper part of the previous stratotype are now assigned to the overlying Jurassic Ha Coi Fm.
Regional extent
Largely exposed in the Mau Son, Au Chau (Lang Son Province) areas, and scattered in the Chi Linh, Ba Che and Luc Nam (Bac Giang Province) and Dap Cau (Bac Ninh Province) areas.
GeoJSON
Fossils
Fresh-water bivalves and phyllopod fossils.
Age
Depositional setting
It is interpreted as the continental facies for the first, and locally, to the lacustrine-marshy facies.
Additional Information