Alyanguz Fm
Type Locality and Naming
Along the village of Alyanguz, Karachatay (eastern part of South Nuratau). I.A. Pyanova in 1982 (371, p.41-46). Stratotype in the area of the village of Kushtamgaly in the valley of the Aktapo River. The subformation name is not recommended for use.
Synonym: Alyanguz Formation, Алянгузская св.
Lithology and Thickness
Divided into two subformations.
Upper subformation - sandy siltstone (aleurolites), often cross-bedded with rounded "boulders" up to 50 times 80 cm in size and with signs of sediment flow, interbedded with siliceous-micaceous, micaceous-quartz slates, and in subordinate amounts, sandstones. Thickness 300m.
Lower - volcanogenic-sedimentary - andesitic tuffs, basalts, basalt lavaclasts, effusive diabases (305), alternating with packages of sedimentary rocks: polymictic sandstones and siltstone (aleurolites) of varying grain size up to gravel, tuffaceous sandstones, quartz-chlorite and siliceous-carbonaceous-chlorite slates. Thickness in Karachatay 250 m, in Gobduntay - about 600 m.
Relationships and Distribution
Lower contact
Contacts are tectonic.
Upper contact
Contacts are tectonic.
Regional extent
Mountains of Karachatay and Gobduntay. The Lower subformation is a lithological and age analog of the Dzhazbulak Fm, and the Upper subformation is an analog of the Naukatsay Fm in the North Nuratau Range. These names are used in geological mapping work in the South Nuratau mining district (Korsakov et al., 1993f.; Khan et al., 1989f.).
GeoJSON
Fossils
Upper subformation – Contains graptolites of the late Llandovery-early Wenlock - Retiolites cf. geinitzianus Barr., Stomatograptus grandis major Boucek and Münch, and others.
Lower – Contains numerous graptolites of the upper Llandovery - Oktavites spiralis zone: Monoclimacis alaica (Obut.), Monograptus priodon (Bronn.), Oktavites spiralis (Gein.), O. proteus (Barr.), Stomatograptus grandis (Sevss.) and others.
Age
Depositional setting
Additional Information