Hongshiya Fm
Type Locality and Naming
The type section is at Hongshiya north of Ercun 22 km northwest of Kunming City, Yunnan. The Hongshiya Fm was named by Guo (1941).
Synonym: (红石崖组), Hongshiyan Fm
Lithology and Thickness
The formation is composed of purple, grayish green and light gray sandstone and shale with a local phosphatic sandstone intercalation. In the type area, the Hongshiya Fm is 250 m thick.
Relationships and Distribution
Lower contact
It rests conformably on the shale and sandstone yielding Tungtzuella of the Tangchi Fm. In Dongchuan, Ningnan, Yanchi, Yanyuan, Luquan, Shiping and Jianshui, the Hongshiya Fm rests conformably on the underlying strata, and in other areas it rests disconformably on the underlying Cambrian. The Hongshiya Fm had previously been referred to the Tremadocian to Arenig clastic strata underlying disconformably the Doucun Fm
Upper contact
It disconformably overlain by the Devonian quartz sandstone with fragmental plants. In the vicinity of Yanjin, northeastern Yunnan, westward to Leibo, Yongshan and the margin of the Xikang-Yunnan paleocontinent, it is conformably overlain by the Qiaojia Fm; and in other area, it is disconformably overlain by the Devonian. The Hongshiya Fm had previously been referred to overlain by the Devonian.
Regional extent
With a persistent lithology, the Hongshiya Fm varies considerably in thickness along the length of its outcrop. In eastern Yunnan, it recorded a thickness of 50-610 m, 60-200 m in southwestern Sichuan, 360-350 m in east margin and 271 m to up to 1000 m in west margin of the Xikang-Yunnan paleocontinent.
GeoJSON
Fossils
This formation yields graptolite of D. (Corymbograptus) deflexus assemblage and Didymograptus “bifidus" assemblage; trilobite Taihuashania brevica, T. omeishanensis, Symphysurus sp. (Yunnan Bureau of Geology and Mineral Resources, 1990); Chitinozoan Lagenochitina obeligis, Eremochitina brevis, Conochitina decipiens (Gao, 1986; Wang and Chen, 1994).
Age
Depositional setting
Additional Information