Karakush Fm
Type Locality and Naming
Named after the Karakush valley, N. Nuratau Range. R.R. Usmanov et al., 1989ф.
Synonym: Karakush Suite, Каракушская св.
Lithology and Thickness
Slates are micaceous-quartz, carbonaceous-clayey, argillaceous, clayey-siliceous black, rarely greenish-gray with rare layers of flaggy siltstone (aleurolites) and lenses of gray clayey-aleurolitic limestones. Thickness more than 100 m.
Relationships and Distribution
Lower contact
Reliable stratigraphic contacts are unknown.
Upper contact
It is assumed that the Karakush Fm builds up the section of the Zhivachisay Fm and gradually transitions into the Dzhalatar Fm (Korsakov et al., 1993f., Usmanov et al., 1999f.; 460).
Regional extent
North Nuratau Range: Narvan, Kichkina-Charvak, Sanzar River; South Nuratau Range: basins of the Sop, Sentyab, Sapparata, Ukhum, Yukary-Uchma streams – basins of the Sharlak stream, Kokcha district. Stratotype by Kichkina-Charvak. Most researchers previously included it in the composition of the Zhivachisay Fm (Chukarov et al., 1968f., 1971f.; Pyatkov et al., 1975f., Usmanov et al., 1984f.).
GeoJSON
Fossils
Contains Tremadoc graptolites - Clonograptus tenellus (Linn.), C. sarmentosus (Nob.), Bryograptus kjerulfi (Lapw.), Br. patens Mat. and others (5); early Ordovician conodonts - Cordylodus prion Lind., Proconodontus cf. tricarinatus Miller., Oistodus proteus Lind., Paracordylodus gracilis Lind., Drepanodus arenatus Pand. and others (Abduazimova et al., 1996f.); together with conodonts, there are fragments of conodont carrier tissues - Nuratodus narvanicus I. Pjan. et G. Pjan. (373; 374); Tremadoc chitinozoa - Conochitina pseudokarinata Paris., Desmochitina ornensis Paris., Siphonochitina modica Abd. and others (20).
Age
Depositional setting
Additional Information