Tieu Giao Fm
Type Locality and Naming
The type section is located in Tieu Giao - Gieng Dạy area, Hoanh Bo Disưict, Quang Ninh Province (N = 20°59’; E = 106°58’).
Synonym: Điệp Tiêu Giao: Trần Đinh Nhân, Trịnh Dánh 1975; Trịnh Dánh 1979, 1980, 1985, 1993, Hệ lằng Tiêu Giao: Trịnh Dánh (in Vũ Khúc et al.) 2000; Nguyễn Công Lượng et al. 2001; Hoàng Ngọc Kỷ et al. 2001. Đệ tứ (part.): Patte E. 1927. Neogen (part.): Dovjikov A.E. et al. 1965. Điệp Dồng Ho (part.): Phạm Văn Quang 1969; Hoàng Ngọc Kỳ et al. 1979. Điệp Rinh Chùa: Trần Đinh Nhân (in Trần Văn Trị et al.) 1977. Hệ tầng Rinh Chùa: Trịnh Dánh (in Phan Cự Tiến et al. 1989; in Vũ Khúc, Bùi Phú Mỹ et al. 1990).
Lithology and Thickness
Conglomerate and Coarse-grained sandstone. This formation includes interbedded weakly cemented conglomerate, gritstone and sandstone, and some thin interbeds or lenses of ash grey clayey shale; cross-bedding is usually observed. The conglomerate pebbles are mainly composed of badly rounded and angular quartz and some sandstone of smali dimension, cemented by sandstone and mudstone. The thickness of the formation varies from 120 to 200 m.
Relationships and Distribution
Lower contact
Unconformably overlies the Dong Ho Fm of Oligocene age.
Upper contact
Regional extent
Tieu Giao, Xich Tho, Troi (Courbet Bay) areas in the Hoanh Bo District, Quang Ninh Province. Correlated to the Rinh Chua Fm of the Cao-Lang Basin.
GeoJSON
Fossils
Flora of Fagus and Phoebe (Fagus cf. stuxbergii - Phoebe pseudolanceolata assemblage).
Quercus cf. neriifoiia - Acer trilobatum - Zelkova zelkovifolia, Phragmites oeingensis - Typha latissima, Fagus cf. stuxbergii - Phoebe pseudolanceolata complexes.
Age
Depositional setting
It is interpreted as coarse Continental deposits extending limitedly in some small troughs.
Additional Information