Shilengshui Fm
Type Locality and Naming
The type section of the Shilengshui Formation is Dashuzhu section, 1 km northwest of Shilengshui, Jiuba Village, or 34 km of south of the seat of Meitan County, Zunyi City, Guizhou Province (107°24’E, 27°26’N). The type section was measured by the No. 3 Brigade of Guizhou Regional Geological Survey Team in 1973. In the type section, the Shilengshui Formation is 240.0 m thick. The Shilengshui Formation first published by Guizhou Bureau of Geology (1974). The name is derived from Shilengshui of Jiuba Village, Shilian Township, Meitan County, Zunyi City, north-central Guizhou Province, and was originally appeared in a 1974 manuscript by Bi Kun from the Guizhou Regional Geological Survey Team (Bi, 1998).
Synonym: （石冷水组）
Lithology and Thickness
The Shilengshui Formation is a carbonate sequence. In the type section the formation is divided into three parts: Lower part consists of grey, light grey, medium- to thick-bedded micritic to fine-crystalline dolomite characterized by leopard-skin and banded structures with brecciated dolomite at top (45.1 m thick); Middle part consists of grey and light grey, thin-bedded laminar dolomite, intercalated with medium- to thick-bedded fine-crystalline dolomite and brecciated dolomite (130.3 m); Upper part comprises grey and light grey, thin-bedded dolomite, intercalated with laminar, medium- to thick-bedded brecciated dolomite (65 m).
Relationships and Distribution
Lower contact
The Shilengshui Fm rests conformably on the Kaotai Fm in most areas of Yangtze Area, South China Region or by the Pingjing Formation in Yenhe and Yingjiang counties of northeast Guizhou Province and eastern Chongqing Municipality. The lower boundary of the formation is defined by the disappearance of the sandy, argillaceous dolomite of the underlying Kaotai Fm.
Upper contact
It is conformably overlain by the Loushankuan Fm in most areas of Yangtze Area, South China Region or by the Pingjing Fm in Yenhe and Yingjiang counties of northeast Guizhou Province and eastern Chongqing Municipality. The upper boundary is defined by the appearance of the thin-bedded, fine- to coarse-grained quartzose sandstone at the base of overlying Loushankuan Fm or Pingjing Fm.
Regional extent
The Shilengshui Formation is exposed in in the Yangze Area of South China Region, distributed in the central and the middle part of northern Guizhou Province and eastern Chongqing Municipality. The thickness of the formation varies from 175‒400 m with maximum thickness in Fuquan County of central Guizhou Province, thinning gradually in all sides with the observed thinnest thickness of 175 m at Baoliansi in Xifeng County, west-central Guizhou Province.
GeoJSON
Fossils
Trilobites Shilengshuia jiubaensis, Jiubaspis brevica, Manchuriella sp., and Proasaphiscus sp. are yielded from the sandy-argillaceous dolomite at the base of the middle part of the formation, and trilobites Manchuriella guichouensis is yielded from interbeds of sandy-argillaceous dolomite at the top of middle part of the formation.
Age
Additional Information