Ovruk Fm
Period:
Proterozoic
Age Interval:
Lower Proterozoic (?), N6
Province:
Nuratau
Type Locality and Naming
Along the Ovruk ravine, N. Nuratau. O.A. Starcev et al. in 1976 (75, p.94). Stratotype in the Ovruk site.
Synonym: Ovruk Suite, Оврукская св.
Lithology and Thickness
Garnet-biotite gneisses and apo-volcanogenic slates, amphibolites (442). Thickness 56m.
Lithology Pattern:
Gneiss
Relationships and Distribution
Lower contact
Lower boundary unknown
Upper contact
Gradually transitions into the Madzherum Fm in the upper part.
Regional extent
Northern Nuratau Ridge, in its central part (Ovruk, Sulukli, etc. sites).
GeoJSON
null
Fossils
Organic remains not found.
Age
The accepted age is based on geological position. Metamorphic association corresponds to the epidote-amphibolite and amphibolite facies undivided. Radiological age data showing the time of metamorphism: hornblende – Ar -577, 631 million years (Baranov et al., 1969); gabbro-amphibolite - Ar - 410, 417 ± 7, 424 million years (O.I. Kim et al., 1976); amphibolite - Ar - 450 million years (O.I. Kim et al., 1976). P.N. Podkopaev et al. (1964) included the rocks of the suite in the composition of the Lower Paleozoic Ittyunsai Fm; O.I. Kim et al. (1976) considered the suite a typical metamorphic basement and assigned it a pre-Baikal age; M.A. Akhmedjanov et al. (75) correlated it with part of the Auminzin Fm of Archean (?) age; in the Strat. Sl. (442) it is conditionally referred to the Proterozoic; R.R. Usmanov et al. (1999), V.S. Korsakov et al. (1993) combined the Ovruk Fm with the Madzherum Fm due to small outcrops and conditionally referred it to the Proterozoic.
Age Span:
Beginning stage:
Calymmian
Fraction up in beginning stage:
0.0
Beginning date (Ma):
1,600.00
Ending stage:
Calymmian
Fraction up in the ending stage:
1.0
Ending date (Ma):
1,400.00
Depositional setting
Depositional pattern:
Additional Information
Compiler:
R.N. Abdullaev, V.V. Mikhailov – In: GeoGPT translation of: “Abduazimova, Z.M. (Ed.), 2001. Stratigraphic Dictionary of Uzbekistan. IMR (Institute of Mineral Resources), Tashkent, 580 pp. (In Russian)”