Bozdontau Formation

Bozdontau Fm

Period:

Proterozoic

Age Interval:

Upper Riphean, K2

Province:
Kyzylkum Region

Type Locality and Naming

Along the Buzdontau Ridge, Bukantau Mountains, Central Kyzylkum. Ya.B. Aysanov et al. in 1979 (1984). Stratotype in the area of the Irliir spring.

Synonym: Bozdontau Formation, Боздонтауская св.

Lithology and Thickness

Packs of dark massive and medium-bedded gray dolomites, dolomitic limestones with layers and lenses of dark gray cherts. Thickness 150-170 m.

Lithology Pattern:

Sandy_claystone

Relationships and Distribution

Lower contact

The formation is exposed in tectonic scales and has no stratigraphic relationships with either underlying or overlying rocks.

Upper contact

The formation is exposed in tectonic scales and has no stratigraphic relationships with either underlying or overlying rocks.

Regional extent

Central Kyzylkum, southern Bukantau Mountains, exposed as a narrow strip on the southern slope of the Irliir Carbonate Ridge. It is correlated with the Akkuduk and upper part of the Kokpatass Formations

GeoJSON

null

Fossils

Contains late Riphean microphytolites - Osagia tenuilamellata Reitl., O. aculeata Z.Zhur., O. corticosa Nar., O. rotundata Z.Zhur., Ambigolamellatus horridus Z.Zhur., Glebosites gentilis Z.Zhur, Radiosus stirpitus Z.Zhur.

Age

K.K.Pyatkov et al. (1975), Ya.B.Aysanov et al. (1984) considered these siliceous-carbonate deposits to be Upper Proterozoic, later, in 1986, Ya.B.Aysanov et al. on the geological map of Central Kyzylkum gave them a Late Riphean-Vendian age; A.K.Bukharin et al. (1990) attributed the B. formation to the Silurian by comparison with the Bogambir Formation; Z.M.Abdazimova et al. attributed the formation to the Upper Proterozoic (19), to the Upper Riphean (16; 17). In the monograph (165) and on the State Geological Map-500 of Uzbekistan (460), a Late Riphean age is accepted.

Age Span:

Beginning stage:

Tonian

Fraction up in beginning stage:

0.7

Beginning date (Ma):

804.00

Ending stage:

Tonian

Fraction up in the ending stage:

1.0

Ending date (Ma):

720.00

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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