Karatash Fm
Type Locality and Naming
Along the Karatash River, northern slope of the North Nuratau Range. P.N. Podkopaev et al. in 1961 (1964f.) studied the Silurian deposits extensively. Stratotype located along the Karatash stream.
Synonym: Karatashian Suite, Каратасская св.
Lithology and Thickness
Terrigenous formations of flyschoid structure - gray-green sandstones, siltstone (aleurolites), slates.
Upper part (thickness up to 100 m) - clay-slate slates and siltstone (aleuropelites).
Middle part (thickness up to 150 m) terrigenous flysch, formed by rhythmically interbedded gray-green clay-slate slates, quartz-feldspar siltstone (aleurolites), and sandstones.
Lower part (thickness about 150 m) sandstones, interbedded with siltstone (aleurolites), less frequently polymictic gravellites. In the sandstones, graded bedding, various hieroglyphs (erosion and filling groove marks) on the lower surface of the layers; in the siltstone (aleurolites), ripple marks, wavy and parallel bedding, and other textures characteristic of turbidite formations.
Total thickness 150-400 m.
Relationships and Distribution
Lower contact
The lower contact is tectonic
Upper contact
The upper is stratigraphically discordant with the Tulebay Fm [? NOTE by J.Ogg - Tulebay Fm is currently assigned to early Devonian, not Silurian] (11; 165; 460).
Regional extent
North Nuratau Range, area of the Merishkor, Mikhin-Daristan, and Koitashek structures, in the form of narrow belts in the watershed part of the range, basin of the Sanzar River; western end of the South Nuratau Range – basins of the Chashma and Kurai streams; southern slopes of the Gobduntau Mountains.
GeoJSON
Fossils
Age
Depositional setting
Additional Information