Alatag Fm
Type Locality and Naming
Eastern South Tianshan. The type section is located at the eastern slope of Karakzile Mt., south of Kümüx in Tosun County, the Xinjiang Uygur Autonomous Region. It was named by Xinjiang Team of Regional Geological Survey in 1965, and was published by the "Regional Scale of Northwest China-Xinjiang” in 1981.
Lithology and Thickness
Limestone and siliciclastics. The section on the eastern slope of Karakzile Mt. is mainly characterized by gray, grayish-black bioclastic limestone, marble, intercalated with chlorite-sericite-quartz schist, metamorphic sandstone and sandy conglomerate. In the bottom are gray pebble limestone and white marble. The thickness is 6167 m.
In the mountainous area north of Karakzile tag, this formation is composed of crystalline limestone, sandstone, siltstone and chlorite-sericite-quartz schist. The thickness is 2100 to 4000 m.
At the south slope of Klatag, the Formation is composed of detrital limestone, oolitic limestone, sandstone and chert, intercalated with conglomerate. The outcropping thickness is more than 181 m.
In the area south of Kaidu River and north of Sairimu River, the formation is characterized by greywacke intercalated with siltstone, conglomerate. The upper part is composed of limestone and dolomite intercalated with calcareous sandstone. It is 3217 m in thickness.
In the Liushugou-Huolangwote area south of Sa'arming Mt., it is intercalated with intermediate-basic to acidic volcanic clastics. The thickness is 5974.6 m in total.
Relationships and Distribution
Lower contact
Conformably or disconformably overlies the Aerpishimaibulak Fm [NOT IN LEXICON].
Upper contact
Conformable contact with the overlying Saarming Fm (Sa'arming Fm)
Regional extent
The formation can be recognized on the eastern slope of Karakzile Mt., North of Karaziletag, at the south slope of Klatag, South of Kaidu River and north of Sairimu River and in the Liushugou-Huolangwote area south of Saarming Mt.
GeoJSON
Fossils
The limestone on the eastern slope of Karakzile Mt.contains coral fossils: Favosites, Pachyfavosites, Heliolites, Emmonsia, and Xystriphyllum.
North of Karaziletag the formation yields coral fossils: Thamnopora incerta, T. ex gr. Tumefacta, Heliolites, Squameofavosites and Pseudamplexus.
At the south slope of Klatag the formation contains coral fossils: Tamnopora cf. reticulata, Wedekindophyllum cf. corneolum.
South of Kaidu River and north of Sairimu River the upper part of the formation contains corals: Disphyllum, Cyathophyllum, Favosites and brachiopods: Camarotoechia, Atrypa.
Age
Depositional setting
Additional Information