Neogene

Paleogene

Cretaceous

Jurassic

Triassic

Permian

Carboniferous

Devonian

Silurian

Ordovician

Cambrian

Neoproterozoic

Mesoproterozoic

Paleoproterozoic

Main source = Abduazimova, Z.M. (Ed.), 2001. Stratigraphic Dictionary of Uzbekistan. IMR (Institute of Mineral Resources), Tashkent, 580 pp. (In Russian) Translated to English by the GeoGPT group, Zhejiang Lab, Hangzhou, China--see About

Gavalbet Beds Formation

Gavalbet Beds Fm

Period:

Silurian

Age Interval:

Lower Silurian (?), N2

Province:
Nuratau

Type Locality and Naming

Near the town of Gavalbet, the Merishkor structure area, northern slope of the N. Nuratau ridge. A.I. Kim, N.M. Larin, 1969 (230, p. 13).

Synonym: Gavalbet Layers, Гавальбетские сл.

Lithology and Thickness

Quartz heterogeneous-grained sandstones and siltstone (aleurolites) containing lenticular bodies and layers (?) (thickness from 10-30 to 100 cm) of biomorphic and clayey limestones with differently aged benthic fauna and flora, rare layers (up to 60 cm) of small-medium clastic mudstone conglomerates and horizons of sandstones with "rounded pebbles" of siltstone (aleurolites). Thickness 220-240m.

Lithology Pattern:

Aus Conglomerate

Relationships and Distribution

Lower contact

Upper contact

Regional extent

Northern Nuratau ridge, northern slope of the town of Gavalbet, area of the village of Chashma-Zrak. I.A. Kim, S.K. Piven et al. (1987f.) include the Gavalbet Beds Fm in the lower part of the Kurbulak Fm

GeoJSON

null

Fossils

In limestone bodies, stromatoporoids - Clathrodictyon">Clathrodictyon inconogrum Birkheed., C. gavalbetum Less., C. vesiculosum Nich., Ecelimadictyon deminutum Less., E. microvesiculosum (Riab.), widespread in the Llandovery-Wenlock of other regions of the world; tabulates - Coenites juniperinus Eichw., Rotalites">Rotalites nuratensis (Chekh.) and others, characteristic of the Lower Silurian; brachiopods - Leptagonia depressa vulgaris Nal., Retziella weberi Nikif., Spirinella striatissima (Holf.), Cyrtia exporrecta Wahl. and others, found in Wenlock-Ludlow deposits; trilobites - Coronocephalus rex (Grabau.); conodonts - Kokelella cf. ranuliformis (Wal.), Panderodus sp. and others, known from Upper Llandovery and Lower Wenlock deposits; Silurian algae - Ortonella aequalis (Heg.), Girvanella problematica Noch. et Ether., Bevocastria conglobataGarw., Solenopora gotlandica (Rot.), Wetheredella silurica Wood. and others.

Age

The complex of organic remains found in limestone bodies is represented by mixed forms from Llandovery to Ludlow inclusive (I.A. Kim et al., 1987). In Strelelev (443) they are assigned to the Wenlock. But, according to Z.M. Abdurazimova (1996), Gavalbet Beds Fm are, most likely, melange boulder formations, fixing the sole of the Silurian deposits nappe on the Mikhin Fm of the Middle Carboniferous and include boulder bodies of carbonate rocks with differently aged organic remains.

Age Span:

Beginning stage:

Telychian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

438.59

Ending stage:

Telychian

Fraction up in the ending stage:

1.0

Ending date (Ma):

432.93

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)”