Dzhengeldin Formation

Dzhengeldin Fm

Period:

Devonian

Age Interval:

Lochkovian-Pragian, K8

Province:
Kyzylkum Region

Type Locality and Naming

By the Dzhengeldy column, South Tamydytau, Central Kyzylkum. P.N.Podkopaev et al., 1965 (457, pp.123-124). Lowermost formation in East Aristanau Reef Fm(local)

Synonym: Dzhengeldinskaya Suite, Дженгельдинская св.

Lithology and Thickness

Central Kyzylkum, Tamydytau, Aristantau, Beltau, Jetymtau Mountains.

Divided into three sub-suites:

Upper (Thickness 100-200m) - alternation of medium-thick bedded dolomites and dolomitic limestones, often organogenic.

Middle (Thickness 150-400m) - clayey limestones with characteristic dark lilac-grey hue.

Lower (Thickness 200m) - at the base a basal pack of lenticularly interbedded quartz-siliceous gravelites, fine-medium pebble conglomerates, replaced upwards by quartz-carbonate siltstones (Aleurites), sandstones with layers of calcareous and clayey slates of a lilac-pink hue, organogenic dolomites, clayey limestones with lenses of carbonate breccias.

Total Thickness 450-800m.

Lithology Pattern:

Dolomite

Relationships and Distribution

Lower contact

It lies with erosion, angular and azimuthal unconformity and basal conglomerates at the base on the Murun Fm

Upper contact

It is overlain conformably by the Madaniyat Fm in Tamydytau and the Dzhalgyztau Fm (Jalgyztau Fm) in Beltau.

Regional extent

GeoJSON

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Fossils

Contains stromatoporoids Paramphipora gracilisporis Less., P. tenuis Yavor., P. cf. anomalis Less., Stromatopora cf. carteri Less., tabulates - Favosites pseudorobustus Kim, F. cf. brusnitzini Peetz., F. ex gr. nitidus Chap.; brachiopods - Hysterolites ex gr nerei (Barr.), Protathyris praecursor Kozl., Amoenospirifer ex gr. thetidus Hav.; rugosans - Battersbia sp. ind., Embolophyllum sp. - Lochkovian-Pragian stages of the Lower Devonian (495; A.K.Bukharin et al., 1990 f.).

Age

On the geological map of Ya.B.Aysanov et al. (1986f.) Dzhengeldin suite in the span of dolomites, limestones, conglomerates is attributed to the Lower Devonian. Belongs to the Lochkovian-Pragian stages of the Lower Devonian. (165; 460).

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:

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