Song Chay Gr
Type Locality and Naming
A lower Thac Ba Fm (Thác Bà Fm) and an upper An Phu Fm (An Phú Fm). Formerly described as a single Song Chay Fm (Tran Van Tri, 1977).
Synonym: Sông Chảy Gr, Song Chay Fm, Sông Chảy Fm.
Lithology and Thickness
A lower Thac Ba Fm (Thác Bà Fm) and an upper An Phu Fm (An Phú Fm). Metamorphic – quartzite, schist and marble
Relationships and Distribution
Lower contact
Uncertain
Upper contact
Uncertain. Tran Van Tri and Vu Khuc (2011) indicate a "pseudo-conformity" to the regionally next younger unit of the Ha Giang Fm containing Middle Cambrian fossils, however the contact was not observed.
Regional extent
Northernmost Vietnam. Distributed in the Lo-Gam Anticline, situated in the external south margin of the Song Chay Granite Massif, in the Thanh Thuy and Tan Quang areas (Ha Giang Province) and Luc Yen Anticlinate (Yen Bai Province) in a band lying between the Song Chay (Chay River) and the Song Lo (Lo River) faults (which are just north and parallel to the Red River Fault) extending southeastward to Hanoi, then plunging beneath Quaternary deposits of the Red River Delta.
GeoJSON
Fossils
None
Age
Depositional setting
The An Phu Fm and Thac Ba Fm were formed in a basin of terrigenous and carbonate sediments having similar composition with the Sa Pa Gr in West Back Bo and equivalent formations in the West of South China.
Additional Information