Kuanyintang Fm
Type Locality and Naming
The type section of Kuanyintang Formation is located at Guanyintang, close to the west of the pass of Lushan Mountain, about 2.5 km southwest of Wenquan Town, or about 17 km southwest of the seat of Lushan City, Jiangxi Province (115°54’E, 29°26’N). The section was remeasured by the Jiangxi Regional Geological Survey Team in 1970. In the type section, the Kuanyintang Formation is 146.48 m thick. The Kuanyintang Formation was named by Li (1931). The name is derived from Kuanyintang (spelled Guanyintang in Hanyu Pinyin) Village in Aikou Township, Xingzi County, Jiujiang City, northern Jiangxi Province. Originally the unit was called Kuanyintang Beds by Li (1931) and was renamed Kuanyintang Formation by Lu (1962) on the basis of a manuscript by the Jiangxi Regional Geological Survey Team, in which the formation name was proposed first.
Synonym: （观音堂组）
Lithology and Thickness
The Kuanyintang Formation is basically a clastic sequence. The formation in the type section is divided into three beds, from bottom up: (1) yellowish green and yellow, argillaceous and ferriferous sericitic shale (78.58 m thick); (2) yellowish green argillaceous and ferriferous sericitic quartzose silty shale in the upper half, and yellowish green, thin-bedded fine sandstone with interbeds of ferriferous sericitic silty shale in the lower half (18.63 m); and (3) grey, greyish green argillaceous and ferriferous sericitic shale (49.27).
Relationships and Distribution
Lower contact
The Kuanyintang Fm is in conformable contact with the underlying Wangyinpu Fm. The lower boundary of the formation is marked by lithological change from black sericitic phyllitic shale of the Wangyinpu Fm to yellowish green argillaceous and ferriferous sericitic shale at the base of Kuanyintang Fm.
Upper contact
The Kuanyintang Fm is in conformable contact with the overlying Yangliugang Fm. The upper boundary is defined by the appearance of dolomitic limestone of the Yangliugang Fm.
Regional extent
The Kuanyintang Formation is exposed in the Jiangnan Slope Area of South China Region, restricted to northwestern and northern Jiangxi Province (Xiushui, Wuning, Jiujiang and Pengze counties of Jiujiang City). The formation is stable in lithology, and becomes thinner eastward, with thickness varying from 160 m to 300 m.
GeoJSON
Fossils
In the type section the Bed 2 of Kuanyintang Formation yields brachiopod Lingula sp. and Bed 3 yields trilobites Redlichia sp. and R. cf. chinensis. In other sections nearby the formation yields trilobites Arthricocephalus chauveaui, Cheiruroides primigenius, Oryctocarella duyunensis and Redlichia chinensis.
Age
Depositional setting
Additional Information