Cholcharatau Formation

Cholcharatau Fm

Period:

Proterozoic

Age Interval:

Lower Proterozoic (?), K3

Province:
Kyzylkum Region

Type Locality and Naming

Along Cholcharatau, South Bukantau, Central Kyzylkum. Ya.B. Aysanov et al. in 1983 (1984).

Synonym: Cholcharatau Suite, Чолчаратауская св.

Lithology and Thickness

The stratotype on Cholcharatau is represented by plagioclase-amphibolite, amphibole, pyroxene-amphibole slates of dark green, greenish-gray color, schistose, banded and folded, variously diaphthorized, containing layers (5-20 cm) of quartzites, microquartzites, biotite-quartz, carbonate-quartz-pyroxene, quartz-chlorite-biotite-plagioclase, quartz-muscovite, talc, and other crystalline slates.

In the Ulken and Dzhaman-Kaskyrtau areas, the section of the suite is mainly composed of bluish-green and green crystalline slates (based on tuffs of basic composition), containing layers (20-50 cm) of dark gray deformed diaphthorized muscovite-chlorite, quartz-chlorite-sericite slates with iron hydroxides and jarosite. According to the data of Ya.B. Aysanov et al. (1984), the main part of the greenstone rocks of the suite was formed from basalts and andesites, their tuffs, tuffites, transformed by regional metamorphism processes, and part of the crystalline slates - from clay-sandy rocks.

Lithology Pattern:

Sandy_claystone

Relationships and Distribution

Lower contact

The lower boundary is unknown

Upper contact

The upper, along Ya.B. Aysanov et al., is conformable with the overlying Kokpatas Fm of middle-late Riphean age. According to Z.M. Abdurazimova et al. (1985, 1996), the relationships between this Cholcharatau Fm and overlying Kokpatas Fm are tectonic.

Regional extent

Central Kyzylkum, South Bukantau, Kaskyrtau Mountains, Altyntau, Kokpatas, Turbay.

GeoJSON

null

Fossils

Organic remains have not been found.

Age

The age is conditionally established as early Proterozoic. The same age is accepted in the monograph (165). On the State Geological Map-500 of Uzbekistan (460), it is dated as conditionally Proterozoic undivided.

Age Span:

Beginning stage:

Stenian

Fraction up in beginning stage:

0.5

Beginning date (Ma):

1,100.00

Ending stage:

Tonian

Fraction up in the ending stage:

0.35

Ending date (Ma):

902.00

Depositional setting

Depositional pattern:

Additional Information

Compiler:

Z.M. Abdurazimova – In: GeoGPT translation of: “Abduazimova, Z.M. (Ed.), 2001. Stratigraphic Dictionary of Uzbekistan. IMR (Institute of Mineral Resources), Tashkent, 580 pp. (In Russian)”