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

Angidan Formation

Angidan Fm

Period:

Silurian, Devonian

Age Interval:

Upper Silurian(?)-Lower Devonian, N8

Province:
Nuratau

Type Locality and Naming

Along the Angidan River, northern slope of the Southern Nuratau Range. S.K. Piven, A.I. Kim (1976). Stratotype in the section of the Aktau carbonate ridge, basin of the Angidan and Sharlak rivers. Lower formation of the Aktau Gr.

Synonym: Angidan Suite, Ангиданская св.

Lithology and Thickness

Lithologically, the section has a two-membered structure:

Upper sub-suite forms the upper reaches of the Angidan River and is traced as a strip of sublatitudinal extension along the Tekobaysay fault and on the northern slope of the Bahiltau Mountains. It is represented by marbled limestones of light gray, white, and yellowish color, massive and thick-bedded with "bodies" of dolomites. In the lower part, a marker horizon is noted, represented by quartz-mica slates, calcareous sandstones, conglomerates, and lenses of clayey marbled limestones

Lower sub-suite is traced along the southern thrust from the Angidan River on the east to the Bashut River on the west and is represented by marbled limestones, yellowish, less often pinkish-gray, layered with lenses of dolomitized limestones and layers of siliceous-clayey rocks.

Total thickness of the suite is 1800m

Lithology Pattern:

Dolomitic limestone

Relationships and Distribution

Lower contact

Within the Southern Nuratau Range, over most of its axial part, the relationships of the Angidan Fm with overlying formations are tectonic.

Upper contact

On the northern slope of the Takhku Mountain, there is probably a normal relationship between the Angidan Fm and the overlying Charhansay Fm.

Regional extent

Southern Nuratau Range, from the Yangaklyk intrusive on the east to the ruins of the village of Paski-Bubak and further to the west, foothills of the northern slope of the Bahiltau Mountains.

GeoJSON

null

Fossils

Upper sub-suite – tabulates Favosites sp. (cf. socialis Sok. et Tes.), F. sp. (cf. suspectus Dubat.), F. sp. (cf. clarus Yanet.), F. sp. (cf. tomensisMiron.), F. sp. (cf. interstinctus Regnell.), Pachyfavosites ex gr. rariporosus Dubat., Neomphyma sp. indet. of Lochkovian-Pragian age (M. 1250 m).

Lower sub-suite – with receptaculites - Receptaculites? sp. ind., tabulates - Thamnoporidae of Upper Silurian age

Age

Age late Silurian? - early Devonian (371; Piven et al., 1976). According to R.R. Usmanov et al. (1999), - early Devonian. In the working reference legend of the South Nuratau ore region, the suite is conditionally dated to the late Silurian-early Devonian with the assumption that other formations of different ages are present in its composition (Korsakov et al., 1993).

Age Span:

Beginning stage:

Lochkovian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

419.00

Ending stage:

Pragian

Fraction up in the ending stage:

1.0

Ending date (Ma):

410.51

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)”