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

Chashmazrak Beds Formation

Chashmazrak Beds Fm

Period:

Silurian

Age Interval:

Pridoli, N2

Province:
Nuratau

Type Locality and Naming

Along the native Chashma-Zrak, southern slope of Mt. Merishkor, N. Nuratau Range. A.I. Kim, N.M. Larin, 1966 (368, pp.94-95). Stratotype in the upper reaches of the Shaly River. They form the upper part of the Chaltash Fm.

Synonym: Chashmazrak Layers, Чашмазракские сл.

Lithology and Thickness

Variegated, organogenic, partially algal, gray limestones. Thickness 75m. Layers with numerous stromatolitic formations are encountered.

Lithology Pattern:

Reef limestone

Relationships and Distribution

Lower contact

Conformably lie on the Shalyn Beds Fm

Upper contact

Conformably overlie the Dzhalpak Fm.

Regional extent

Northern Nuratau Range, northern slope of the Ishkap area, northern slope of the Shaly elevation.

GeoJSON

null

Fossils

Contains brachiopods - Gypidula ex gr. pelagica Barr., Lanceomionia tarda Barr., Atrypopsis megaerella (Plod.), Protathyris praecursor Kozl., Retziella weberi Nikif., Tadschikia wilsoniaformis Nikif., Nikiforovaena lynxoides (Nal.), N. isfarensis Nikif., N. favasiticus Nikif., Spinatrypa pseudosquamosa Nikif.; less stromatoporoids - Densastroma podolicum (Yavor); rugosans - Fasciphyllum kokshalicum Pavl.

Age

Belong to the Pridoli stage of the upper Silurian.

Age Span:

Beginning stage:

Pridoli

Fraction up in beginning stage:

0.0

Beginning date (Ma):

422.73

Ending stage:

Pridoli

Fraction up in the ending stage:

1.0

Ending date (Ma):

419.00

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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