Murun Formation

Murun Fm

Period:

Ordovician

Age Interval:

Caradocian-Ashgillian, K5, K8

Province:
Kyzylkum Region

Type Locality and Naming

Along Muruntay, South Tamdytau, Z.M.Abdazimova et al. in 1991, as recommended by the Stratigraphy and Geological Map Commission of the GPDK Kyzylkum Geodynamic Polygon, it was separated from the Besapan suite (1993f.), 1998 (9, pp. 3-14). The stratotype is in the Besapan area.

Synonym: Murunskaya Formation, Мурунская св.

Lithology and Thickness

The section consists of greenish-gray, tobacco-green, yellowish-green rhythmically alternating quartz and polymictic sandstones of various grain sizes, siltstone (aleurolites), clay-schist slates, argillites, and rarely gravelites. The section has a flysch-like structure. In the siltstone (aleurolites), there are numerous traces of the action of mudflows: bottom currents, erosion of sediments, dragging and rolling of fragments, and in the coarse-grained rocks - graded bedding. Thickness 300-400m.

Lithology Pattern:

Fine-grained sandstone

Relationships and Distribution

Lower contact

The lower contact is tectonic

Upper contact

The upper stratigraphically discordant with the carbonate rocks of the Dzhengeldin Fm.

Regional extent

South Tamdytau, south of the Muruntay carbonate ridge, small outcrops in the Yasvai ore field, Auminza-Beltau, Daugyztau, Aristantau. Muron Fm corresponds to the upper sub-suite of the Besapan Fm ("green Besapan").

GeoJSON

null

Fossils

In sandstones and siltstone (aleurolites), chitinozoa - Desmochitina minor f. typica Eis., D. minor erinacea Eis., Jenkinochitina tanvillensis (Paris.) and others, found in the sections of the Caradoc-Ashgill.

Age

The age is determined by comparison with the Taiman Fm in S. Tamdytau and the Lyupetskaya suite in S. Bukantau. A.K. Bukharin et al. (122; 1990f.) attributed it to the Wenlock of the Lower Silurian, M.A. Akhmedjanov et al. (75; 79), Z.M. Abdazimova et al. (1993f.; 460) - to the Ordovician - Lower Silurian; Z.M. Abdazimova, R.N. Abdullaev (9) and in the monograph (165) to the Upper Ordovician; on the geological map of the C. Kyzylkum m-ba 1:100000 Ya.B. Aysanov et al. (1986f.) date these deposits to the Middle-Late Ordovician. Analogue of the Jadyr Fm (Dzhadyr Fm) of the S. Nuratau ridge.

Age Span:

Beginning stage:

Sandbian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

458.18

Ending stage:

Katian

Fraction up in the ending stage:

1.0

Ending date (Ma):

445.21

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)”