Sultanuizdag Formation

Sultanuizdag Fm

Period:

Silurian, Devonian

Age Interval:

Upper Silurian-Lower Devonian, U5

Province:
Ustyurt-Sultanuzdag

Type Locality and Naming

Along the Sultanuzdag Mountains Yu.A. Likhachev, V.S. Vladimirsky, E.V. Malova, S.S. Shulz (Jr.) in 1961 (266, p.54). The stratotype is in the middle course of the Dzhamsay River. Upper formation in

Synonym: Sultanuzdag Suite, Султануиздагская св.

Lithology and Thickness

It is divided into two sub-suites: Lower one consists of quartz-feldspathic sandstones and siltstones with layers of mica-quartz and amphibole slates. The Upper slates are biotite-quartz and muscovite-biotite-quartz. As they extend to the southeast, the slates change to gneiss-like (gneissoid) garnet-staurolite slates with increasing degree of metamorphism. In the vicinity of the Aktaw intruder, the rocks of the suite have been transformed into hornfels due to contact metamorphism. Thickness up to 500 m.

Lithology Pattern:

Claystone

Relationships and Distribution

Lower contact

The age is determined by the conformable bedding on the Urusay Fm

Upper contact

Conformably overlying faunally characterized formations of the Dzhamansay Fm (Dzhamsay Fm) (Keshishyan, 1995).

Regional extent

The suite borders the northeastern and northern Aktaw granodiorite massif and its eastern field.

GeoJSON

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Fossils

Age

Radiological data obtained by the K/Ar method are 260-290, 310, 465, 780, and 823 million years. Based on the last two dates, M.A. Akhmedjanov et al. (73; 76) consider the age of the suite to be conditionally Riphean-Vendian, while O.I. Kim (1974) considers it to be Proterozoic. In the Strat. Sl. (441); by Yu.A. Likhachev et al. (266); by S.S. Shul'ts (ml.) (508) it is conditionally referred to the Lower Silurian; on the State Geol. Map-500 of Uzbekistan (460) it is included in the composition of the Sultanuizdag suite of the conditional Proterozoic.

Age Span:

Beginning stage:

Pridoli

Fraction up in beginning stage:

Beginning date (Ma):