Karwa Fm
(29), mid-Guadalupian Epoch (mid-Middle Permian)
Type Locality and Naming
The type section is located in the area of Haxiakelike River, Alka Mt., Region of Kulun Mt., Xinjiang. It was named by the 1st Regional Geological Survey Expedition of Xinjiang in 1984.
Lithology and Thickness
Limestone and Clastics. Divisible into three parts: Lower part composed is of grey-black bioclast-bearing limestone, intercalated with grey calcareous fine-grained sandstone. Middle part consists of purple phyllite and calcareous siltstone. Upper part represents rose and light-red limestones, intercalated with grey-green feldspar-clastic sandstone. Thickness is 1452 m
Relationships and Distribution
Lower contact
Uncertain; it is in Fault contact with the underlying Biyunshan Fm
Upper contact
Uncertain, no top of it having been found
Regional extent
Distributed in the area of the major crest of the Alkar Mt., with a thickness of 8600 m; while in the Ridi Pagoda area it thickness reaches as great as over 5853 m, and in the Yidaoliang area to the southeast of the Arqikekule Lake its thickness is of over 8604 m.
GeoJSON
Fossils
Fusulinida represented by the Polydiexodina-Neoschwagerina assemblage whose major members are the Polydiexodina praecursur, P. douglasi, Pseudofusulina sp., Ozawainella sp., Eoparafusulina sp. and Toriyamaia sp.;
Brachiopods comprising Leptodus nobilis, Orthotichia sp., Enteletes xinjiangensis, Marginifera sp., and Linoproductus lineatus;
Bivalves such as Schizodus sp.; Corals such as Waagenophyllum sp.; and Bryozoan represented by Fistulipora sp., etc.
Age
Depositional setting
It is interpreted as very thick flysch deposits.
Additional Information