Uchkuduk-Sil Formation

Uchkuduk-Sil Fm

Period:

Silurian

Age Interval:

lower Wenlock, K9, K7

Province:
Kyzylkum Region

Type Locality and Naming

Named after the Uchkuduk collective farm, Kuldjuktau Mountains, Central Kyzylkum. Ya.B. Aysanov et al. in 1963 (42, p.23; 44, p.23-25).

Synonym: Uchkuduk Suite, Учкудукская св.

Lithology and Thickness

Essentially clayey limestones with subordinate layers of cherts, sandstones, siltstone (aleurolites), shales, and rhyolite tuffs. Thickness 50-170m.

Lithology Pattern:

Clayey limestone

Relationships and Distribution

Lower contact

Conformably overlies the Darbazin Fm west of the Tozbulak intrusion and on the southern and northern slopes of Beltau; in other places, contacts are tectonic.

Upper contact

Conformably overlain by the Dzhangel'din Fm (Dzhangeldin Fm) (165; 441;460).

Regional extent

Central and western parts of the Kuldzhuktau Mountains in the form of narrow sublatitudinal strips, often bounded by faults, predominantly on the flanks of anticlinal folds.

GeoJSON

null

Fossils

Tabulates - Antheralites hemiseptopsis Lel., Favosites cf. gothlandicus Lam., F. favosiformis Sok., Halysites cf. catenularis Lin., Multisolenia frivola Klaam., Catenipora gotlandica Sok., and others; brachiopods - Eospirifer radiatus Sow., Acanthospirifer edelschteini Men., Atrypoidea cf. prunus Dalm., Eridorthis cf. reinwaldti Nikif., and others; crinoids - Megalocrinus brevis Schew., M. latebrosus Schew., Obuticrinus bullosus Yelt., Pentagonocyclicus subhelena Yelt., and others.

Age

Early Wenlock age is established by tabulates

Age Span:

Beginning stage:

Sheinwoodian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

432.93

Ending stage:

Sheinwoodian

Fraction up in the ending stage:

1.0

Ending date (Ma):

430.62

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)”