Hongtiegou Fm
Type Locality and Naming
Type section of Hongtiegou Formation is the Quanjishan section, located at Heitupo in Hongtiegou Village, near Quanjishan Mountain, Da Qaidam, Haixi Prefecture, Qinghai Province (95°51’E, 37°25’N). The section lies about 60 km southeast of Da Qaidam Town, and was remeasured by Wang Yunshan and Chen Jiliang from Qinghai Institute of Geological Survey in 1983. It is the moddle portion of the same type section shared by the underlying Heitupo Formation and overlying Zhoujieshan Formation, each embraces the Bed 1‒3 and Bed 7‒10 respectively, while the Hongtiegou Formation embraces the Bed 4‒6. In the type section, the formation is 17.50 m thick.
Synonym: （红铁沟组）
Lithology and Thickness
The Hongtiegou Formation is a glacial conglomerate sequence. It includes the middle three beds of the Quanjishan type section (Bed 4 to 6), from bottom up: 4, yellowish green and grey glacial gompholite (5.00 m thick) [NOTE: "gompholite" is a German term from the Alpine molasse basin, and seems to be coarse fluvial deposits]; 5, purple red glacial gompholite with interbeds of yellow calcareous dolomite (thickness of single bed is 2‒6 cm) in the lower part (11.70 m); 6, light greyish green glacial gompholite with obscure lamination (0.80 m).
Relationships and Distribution
Lower contact
The Hongtiegou Fm rests disconformably on the underlying Heitupo Fm, but occasionally in conformable contact with the latter formation. The lower boundary of the Hongtiegou Fm is defined by the plane of disconformity
Upper contact
Iis overlain conformably by the thick-bedded dolomite of Zhoujieshan Formation.
Regional extent
The Hongtiegou Formation is exposed in the Qaidam Area of the Qaidam -Qilian-Alexa Region, restricted mainly in the Quanjishan area, Haixi Prefecture, Qinghai Province, and it outcrops also at Shihuigou, which lies about 20 km east of the Quanjishan Mountain. At Shihuigou, the formation is 108 m thick.
GeoJSON
Fossils
The formation yields no fossil.
Age
Depositional setting
Additional Information