Dzhaksan-Sil Formation

Dzhaksan-Sil Fm

Period:

Silurian

Age Interval:

Upper Wenlock, K5a

Province:
Kyzylkum Region

Type Locality and Naming

Along the section of Jaksan, Tamdytau Mountain, Central Kyzylkum. A.K. Bukharin, I.A. Maslennikova, A.K. Pyatkov, 1985 (122, p.68).

Synonym: Dzhaksanskaya Formation, Джаксанская св.

Lithology and Thickness

Poorly sorted sandstones, siltstone (aleurolites), phyllitic slates, gravels, conglomerates, and coarse clastic rocks are associated with the Lower horizons of the section. Thickness 500m.

To this suite, A.A. attributed and klippen (70-80m), composed of bedded and massive limestones, containing layers of calcareous siltstone (aleurolites).

Sh.Sh. Sabdyushov (392) described these deposits in different types of sections: Terrigenous and Carbonate. The same opinion is held by Z.M. Abdazimova et al. (1989, 1993). The Terrigenous lower part of the suite is a complete analogue of the Kuskumbay Fm, and the Carbonate klippen are facies analogues of the Kosbulak Fm suite, as understood by A.I. Kim et al. (1974) and Z.M. Abdazimova (1996, 165).

Lithology Pattern:

Sandstone

Relationships and Distribution

Lower contact

With apparent conformity, it lies on the “Jamankynyrskaya” suite (Dzhamankynygr Fm)

Upper contact

It is conformably overlain by tuffaceous sandstones of the upper Silurian (443).

Regional extent

Northern Tamdytau, right bank of Kuskumbaysay, southern foothills of Aktau Mountain, Jaksan and Ajrikty settlements.

GeoJSON

null

Fossils

Contains graptolites - Testograptus testis (Wagt.), Monoclimacis cf. flumendosae (Gort.) and others, characteristic of the upper Wenlock (292).

To this suite, A.A. attributed and klippen (70-80m), in the limestones, numerous remains of stromatoporoids, tabulates, corals, and other benthic fauna of Wenlock-Ludlow age are found.

Age

Fossil data indicates upper Wenlock

Age Span:

Beginning stage:

Homerian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

430.62

Ending stage:

Gorstian

Fraction up in the ending stage:

1.0

Ending date (Ma):

425.01

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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