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

Zhivachisay Formation

Zhivachisay Fm

Period:

Cambrian, Ordovician

Age Interval:

late Cambrian-early Ordovician, N4

Province:
Nuratau

Type Locality and Naming

Along Zhivachisay, N. Nuratau Ridge. P.N. Podkopaev et al. in 1960 (1964), in the volume of n. Silurian. Stratotype Along Zhivachisay.

Synonym:

Lithology and Thickness

The section consists of three packages.

1. Lower: Limestone-slate, represented by medium- and thick-bedded gray polymictic limestones, interbedded with calcareous, siliceous-micaceous, carbonaceous-siliceous, less frequently silty (aleuritic) slates of gray, bluish-gray, less frequently dark gray color. In the slates, there are nodules, lenses, and layers of dark quartz-siliceous rock, in subordinate quantities, layers (2-10 cm) of gravel, polymictic dolomitized sandstones. Thickness about 20-35 m.

2. Middle: Siliceous-claystone (argillaceous), composed of clayey, clayey-aleuritic, siliceous-clayey, siliceous-micaceous slates of greenish- and bluish-gray color, alternating with clayey-calcareous, clayey-carbonaceous-calcareous dolomitized varieties of black, dark gray, and gray color (yellowish-brown and brown on the surface). Thickness about 40 m.

3. Upper: Slates with numerous nodules, lenses, and layers of quartz-siliceous rock, filled with cyanobacterial formations - Nuratella varia Pjan., N. incrustans Pjan., Stereophycus schochycus Pjan., Renatina miagkovae Pjan. In subordinate quantities, layers and horizons of medium- and thick-bedded gray limestones. Thickness no more than 20 m.

Total formation thickness is approx. 100 m.

Lithology Pattern:

Claystone

Relationships and Distribution

Lower contact

Stratigraphic contacts are not established

Upper contact

It is assumed that it is overlain by the Karakush Fm or Kaltadavan Fm

Regional extent

Northern slope of the North Nuratau Range - from the westernmost spurs (Shokhsay) to the eastern end (Sanzar River); South Nuratau - Kuraissay Basin, Kokcha area; Gobduntay - southern strip of limestone-slate deposits.

GeoJSON

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Fossils

Age

According to R.R. Usmanov, the Zhivachisay Fm lies on the Kansay Fm. The early Paleozoic age of the limestone-slate deposits was indicated as early as 1937 by N.A. Smirnov. However, the absence of organic remains determining the age of the rocks allowed subsequent researchers to interpret their stratigraphic position ambiguously, from the Cambrian to the Silurian, inclusive (Posokhov et al. (1969) - early Silurian, middle Llandovery; A.K. Bukharin et al. (1982, 1990) - conditionally late Ordovician-early Silurian; A.K. Pyatkov et al. (1999) - middle Cambrian-early Ordovician; E.V. Chukarov et al. (1968), N.R. Asatullaev et al. (1970) - late Cambrian-early Ordovician; V.S. Korsakov et al. (1993), R.R. Usmanov et al. (1999) - middle-late Cambrian). Finds of Tremadocian graptolites in the overlying Karakush Fm (12) and late Cambrian and early Ordovician conodonts (Abduazimova et al., 1993, 1996) in the limestone-slate rocks of the Zhivachisay Fm determined the age of the suite as late Cambrian-early Ordovician. In the monograph (165) and on the State Geological Map-500 of Uzbekistan (460), the age of the suite is late Cambrian-early Ordovician.

Age Span:

Beginning stage:

Paibian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

497.00

Ending stage:

Tremadocian

Fraction up in the ending stage:

0.5

Ending date (Ma):

481.96

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)”