Xiajiang Gr
Type Locality and Naming
Northeast Guizhou. The Xiajiang Gr was named by Wang Y.L. (Wang Yuelun) in 1936, and published in the Report of Minerals of eastern Guizhou Province (the former Geological Survey of China). The naming sections are located in Zaibian of Congjiang County and Furongba, of Yinjiang County, Guizhou Province.
Synonym: （下江群）
Lithology and Thickness
The Xiajiang Gr is subdivided into six formations in SE Guizhou, from bottom to top: (Guiyan Fm), Jialu Fm, Niaoye Fm, Fanzhao Fm, Zhangjiaba Fm, Qingshuijiang Fm, Pinglue Fm and Longli Fm. In NE Guizhou, the upper three formations are absent, and the lowest formation (below the Jialu) is indicated as a Furongba Fm. The group consists mainly of slightly metamorphosed sandstone and shale, tuffaceous sandstone and minor carbonate rocks. The thickness northwest of Fanjing Mountain is about 4500 m. The thickness in southeast Guizhou is over 10,000 m.
[Figure: The Stratigraphic column of the Xiajiang Gr. in Guizhou Province. A-Volcanic ash beds in the Jialu Fm and zircons from the ash bed.]
Relationships and Distribution
Lower contact
Upper contact
The group is overlain by earliest Nanhuan (Liangjiche Fm in NE Guizhou; Chang'an Fm in SE Guizhou).
Regional extent
East Guizhou. The group is well developed in the east part of Guizhou, with the thickness and volcanic rocks increasing southwards, and fluvial sediments gradually increasing.
GeoJSON
Age
Depositional setting
It is interpreted as a suite of shallow-sea sediments from shelf to slope.
Additional Information