Gaurdak Gr

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

Gaurdak Gr

Period:

Jurassic

Age Interval:

late Kimmeridgian - Tithonian, B1-B3

Province:
Bukhara-SW Gissar

Type Locality and Naming

Along the city and settlement of Gaurdak, W. Turkmenistan. V.P. Miroshnichenko, 1933 (303, p.40). Stratotype in the wells of the Gaurdak and Tyubegatan plateaus. Previously it was called the Gypsum Formation (499), Salt–Gypsum Formation (133), and Koshkhaus Formation (343, 344, 446). Later, it was elevated to the rank of the Gaurdak Gr.

Synonym: Gaurdak Suite, Гаурдакская сер., Gaurdak Fm, Gypsum Fm, Khodzhaikan Fm

Lithology and Thickness

At the bottom, alternation of anhydrites and dark limestones (sometimes this part is included in the underlying Kugitang Fm); in the Middle, salt or anhydrites with interlayers of red siltstone (aleurolites) and clays in the upper part, Upwards anhydrites with interlayers of red siltstone (aleurolites) and clays, replaced on the east by marls. Thickness 70-850m.

Capping Anhydrite member of Gaurdak Fm, Upper Salt member of Gaurdak Fm, Middle Anhydrite member of Gaurdak Fm, Lower Salt member of Gaurdak Fm, Lower Anhydrite member of Gaurdak Fm

Lithology Pattern:

Gypsum-Anhydrite

Relationships and Distribution

Lower contact

Lies conformably or with a break on the Kugitang Fm

Upper contact

It is conformably overlain by the Karabil Fm at base of the Takchiyan Gr.

Regional extent

Southwestern Gissar, its southern slope, Mechetli and wells of the Bukhara-Karshinsky region.

GeoJSON

null

Fossils

Contains marine bivalve mollusks - Camptonectes duabensis Rep., C. cf. grenieri Contej., Chlamys mantochensis Et. and others; brachiopods - Zeilleria bucculenta Lor. and others. In the limestone interlayers of the lower part of the Gaurdak Gr, ammonites - Lithococeras sp., Othetoceras sp. of the upper Oxfordian - lower Kimmeridgian were found.

Age

Used span of Kimm-Tith, following USGS and Mordvintsev. Belongs to the upper Oxfordian - Tithonian, A.V. Danov (188); V.I. Bratash (117; 118) assigned the Gaurdak Gr to the Lower Cretaceous. [The strat columns of both Mordvintsev and Fursich limit the Gaurdak Fm in its evaporitic sense to the Tithonian (with the Khodzhaipak Fm evaporites in Kimm = “basinal type” of Fursch => South Gissar (see USGS map).

Age Span:

Beginning stage:

Kimmeridgian

Fraction up in beginning stage:

0.25

Beginning date (Ma):

153.40

Ending stage:

Tithonian

Fraction up in the ending stage:

1.0

Ending date (Ma):

143.10

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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