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

Obay Formation

Obay Fm

Period:

Devonian

Age Interval:

Givetian-Frasnian, N2

Province:
Nuratau

Type Locality and Naming

By Obay village, N. Nuratau Ridge. I.A.Kim, S.K.Piven and others in 1987 (460, p. 126). Stratotype on the right bank of Aidynsai.

Synonym: Obais Suite, Обайская св.

Lithology and Thickness

Divided into two sub-suites.

Lower - massive nodular limestones. Thickness 60-200m. Upper - oolitic limestones. Thickness 270m.

Lithology Pattern:

Oolitic limestone

Relationships and Distribution

Lower contact

Bounded below by a steeply dipping sublatitudinal fault, along which it contacts the limestones of the Dzhalpak Fm [which is Lochkovian-Pragian, hence Taraklin Fm and Kakir Fm have ages between].

Upper contact

A conformable contact with the overlying deposits of the Syrt Fm is assumed.

Regional extent

Northern Nuratau Ridge, watershed part of Dzhalpak city in the Merishkorskaya structure.

GeoJSON

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Fossils

Lower – Contains brachiopods Stringocephalus burtini Defr., characteristic of the Givetian.

Upper – Contains foraminifers - Sorbiella cf. fungeiformis Pojark., Uralinella sp., Eogeinitzina cf. devonica Lip., Parathurammina cf. paracushmani Reil., characteristic of the Frasnian, and forms typical for the Famennian - Asterophaera pulchra Reitl., Parathurammina ex gr. guleimanovi Lip., Irregularina sp., Cribrosphaeroides aff. ovalis Pojark., Eovolutina sp. (I.A.Kim et al., 1987).

Age

V.S.Korsakov et al. (1993), R.R.Usmanov et al. (1999) and on the State GeolMap-500 of Uzbekistan (460) refer it to the Givetian-Famennian of the Middle-Upper Devonian.

Age Span:

Beginning stage:

Givetian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

385.30

Ending stage:

Famennian

Fraction up in the ending stage:

1.0

Ending date (Ma):

359.30

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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