Kayrak-Ord Fm
Period:
Ordovician
Age Interval:
Upper Ordovician Ashgillian(Hirnantian), CK9c
Province:
Chatkal-Kuramin Region
Type Locality and Naming
Named after the abrasive sandstones present in the suite and used for making millstones in the Mogoltay Mountains, Tajikistan. B.N. Nasedov in 1935; E.D. Karpova, 1959 (219, p.88). Hypostratotype in the lower course of the Mashrapsay.
Synonym: Kayrak Suite, Кайракская св.
Lithology and Thickness
Interbedded quartz sandstones, siltstone (aleurolites), and claystones. Up to 400 m.
Lithology Pattern:
Sandstone
Relationships and Distribution
Lower contact
Normally overlies the Kurusay Fm
Upper contact
Conformably overlain by the Urubulak Fm
Regional extent
S.-W. part of the Mogoltay Mountains, lower course of the Mashrapsay.
GeoJSON
null
Fossils
In the upper part contains graptolites - Glyptograptus persculptus (His.), Amplexograptus sp., etc.
Age
Fossil data characterizes the Ashgillian (Hirnantian) age of the suite
Age Span:
Beginning stage:
Hirnantian
Fraction up in beginning stage:
0.0
Beginning date (Ma):
445.21
Ending stage:
Hirnantian
Fraction up in the ending stage:
1.0
Ending date (Ma):
443.07
Depositional setting
Depositional pattern:
Additional Information
Compiler:
A.I. Kim – In: GeoGPT translation of: “Abduazimova, Z.M. (Ed.), 2001. Stratigraphic Dictionary of Uzbekistan. IMR (Institute of Mineral Resources), Tashkent, 580 pp. (In Russian)”