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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

Zarmas Formation

Zarmas Fm

Period:

Jurassic

Age Interval:

Early Callovian - Middle Oxfordian, B2

Province:
Bukhara-SW Gissar

Type Locality and Naming

Named after the village of Zarmas, Yakkobag Mountains, Southwest Gissar.

V.V. Kurbatov, E.A. Repman 1982 (253, p.42), N.V. Beznosov and V.V. Kurbatov since 1980 used the name G.S. Chikryzov, given for the lower part of the carbonate formation in the Yakkobag Mountains. Stratotype in the section of Zakharli, Kugitangtau, Southwest Gissar. Lowermost formation of Kugitang Gr in South Gissar (Deeper-water and Evaporite for Late Jurassic). Stratotype in the section of Zakharli, Kugitangtau, Southwest Gissar.

Synonym: Zarmasskaya Suite, Зармасская св.

Lithology and Thickness

Gray oncoidoolitic, less frequently clayey and biogenic limestones, in the coastal zone conglomerates, gravelites, sandstones. Thickness 25-351m.

Lithology Pattern:

Oolitic limestone

Relationships and Distribution

Lower contact

Conformably overlies the Baysun-Jur Fm.

Upper contact

Conformably overlain by the Zakharlin Fm or Tupolang Fm. Starting from the northeast, the Kugitangtau, including the Yakkobag Mountains and Surkhantau, Zarmas Fm conformably overlies (is overlain by?) the Kurek Fm, sliding stepwise over the reef-bar systems.

Regional extent

Southwest Gissar, Mechetli, southern slope of Gissar, wells of the Bukhara-Karshinsky region.

GeoJSON

null

Fossils

Contains in the lower part ammonites - Macrocephalites pila Nik., higher ammonite zones: Kosmoceras jason, Peltoceras athleta and layers with marine bivalve mollusks - Pholadomya murchisoni morphotype gamma and Ceratomya gigantea; layers with Inoperna perplicata and Isognomon promytiloides; layers with Ceratomya gigantea Pak sp. n., Pholadomya murchisoni morphotype gamma Pak sp. n. and others; brachiopods - Sphaeroidothyris trifonovi Moiss., Zeilleria bolkarensis Moiss. and others; foraminifers - Karaisella sp.; corals - Thecosmillia cf.vurguini Babaev, Stephanostraca jurassica Roniewic, Stylina sp. and others.

Age

Early-middle Callovian age of the suite and its sliding boundaries are determined by ammonites, marine bivalve mollusks, foraminifers. Lower boundary of the Zarmas Fm slides within the lower Callovian. Upper boundary of the Zarmas Fm in Kugitangtau is drawn in the upper part of the middle Callovian. In the southwest part of Susyztau (Khatak) the upper boundary of the Zarmas Fm passes between the middle and upper Oxford, and in the section of Pyandjob it coincides with the boundary of the lower and middle Oxford, in the northeast part of Susyztau (Ilolik, Sayrob) and further to the north and east, the upper boundary of the Zarmas Fm coincides with the boundary of the upper Callovian and lower Oxford. Early Callovian - middle Oxfordian age of the suite and its sliding boundaries are determined by ammonites, marine bivalve mollusks, and foraminifers. (59; 60; 165; 339; 383, tables 4,5; 462; 466).

Age Span:

Beginning stage:

Callovian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

165.29

Ending stage:

Callovian

Fraction up in the ending stage:

0.35

Ending date (Ma):

163.97

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)”