Huanxingshan Fm
Type Locality and Naming
The Huanxingshan Fm was named by No.1 Xinjiang Party of Regional Geological Survey in 1981, and was published by Zhang Tairong (1990). The Huanxingshan Fm was followed by Xiao Bing (1990). Zhong Rui and Hao Yongxiang (1994) remeasured and studied in detail the type section, and divided the Huanxingshan Fm into two lithological members.
Synonym: (环形山组）
Lithology and Thickness
The formation is divided into two parts. The lower through middle part is composed of grayish black medium- to thin-bedded bioclastic micritic limestone and grayish black intramicrite intercalated with local black thin-bedded siliceous limestone. The upper part is represented by gray to dark gray argillutite and argillaceous sandstone.
Relationships and Distribution
Lower contact
The Huanxingshan Fm rests conformably on the thick-bedded limestone at the top of Elantag Fm
Upper contact
With a covered upper boundary.
Regional extent
From the type area to Yaolesayi, the Huanxingshan Fm exhibits a decreasing siliceous and increasing sandy and muddy content of the sediments and an increased thickness up to 320 m.
GeoJSON
Fossils
This stratigraphic unit yields conodonts, in ascending order, of Eoplacognathus suecicus-Amorphognathus assemblage, Pygodus serra-P. proatus assemblage and Pygodus aff. anserinus assemblage; Nautiloids of Handanoceras assemblage; coral of Billingsaria-Amsassia assemblage; Stromatopora of Pachystylostroma assemblage; brachiopods of Hesperorthis-Glyptorthis assemblage; trilobites of Ampyx-Lochobasilicus assemblage; gastropod of Liospira cf. Micula-Maclurites kalakunlunensis assemblage; bryozoan of Diplotrypa-Mestotrypa assemblage; ostracoda of Primitia-Bythocypsis assemblages; graptolites Glyptograptus cf. euglyphus, H. cf. teretiusculus and Amplexograptus maximus.
Age
Depositional setting
Additional Information