Shuigoukou Fm
Type Locality and Naming
No type section is assigned when Lu (1962) published the unit. An auxiliary section, Yuejiaping section, was proposed by Xiang (1981d) as representative section of the formation. This section lies at side of the highway between Yuejiaping and Wangjiadian villages, 6.5 km south of Xianghe Town, or about 32 km south of the seat of Shangnan County, Shangluo City, southeastern Shaanxi Province. (110°53’26” E, 33°14’50” N). In the auxiliary section, the Shuigoukou Formation is 47.3 m thick.
Synonym: （水沟口组）
Lithology and Thickness
The Shuigoukou Formation is a sequence with siliceous rocks in lower part and carbonate rocks in middle and upper parts. Lower part, mainly consists of black, dark grey, thin-bedded siliceous rack, carbonaceous siliceous rack and yellowish grey and black aluminous shale with phosphoric nodules; the middle and upper parts consists of multi-colored (dark grey, greyish purple, light grey, greyish white) limestone, argillaceous limestone, and dolomitic limestone.
Relationships and Distribution
Lower contact
The Shuigoukou Fm rests disconformably on Tongying Fm. The lower boundary of the formation is marked by the disconformable plane.
Upper contact
It is conformably overlain by Yuejiaping Fm, east of Shanyang Town, and by Shihwengtzu Fm, west of Shanyang Town. The upper boundary is defined by the appearance of thick-bedded dolomite at the base of the Shihwengtzu Fm or the appearance of purple dolomite at the base of of Yuejiaping Fm.
Regional extent
The Shuigoukou Formation is exposed in the Jiangbei Slope Area of South China Region, restricted to southeastern Shaanxi Province (Shangnan, Shanyang, Zhen’an, and Ningshan counties). The thickness of the formation varies from 19 to 60 m.
GeoJSON
Fossils
The lower part of the Shuigoukou Formation yields hylolithid Hyolithes sp.; the middle-upper part of the formation yields trilobites Kootenia yui., Palaeolenus quadratus., Redlichia murakamii, and R. chinensis and Shifangia yefanggouensis.
Age
Depositional setting
Additional Information