Vanchdarin Fm
Type Locality and Naming
It was identified in 1939 by M. I. Shabalikin in the axial part of the Darvaz Ridge, in the basin of the Bivachny Glacier, described in 1968 by E. F. Roman'ko and E. S. Cherny under the name of Fedchenkovskaya suite.
Synonym:
Reference section:
Lithology and Thickness
It is composed of banded dark and light gray limestones with interlayers of clayey slates, sandstones, rarely limestone conglomerates. In the Darvaz Ridge, M. I. Shabalikin attributed to it the greenstone diabases and porphyrites containing interlayers of limestone and in agreement with Overlaying with banded limestones, analogous to those mentioned above. The incomplete thickness of the suite is 1000 m.
Relationships and Distribution
Lower contact
Its contacts are tectonic.
Upper contact
Its contacts are tectonic.
Regional extent
It is widespread in the central and western parts of the Karakul region.
GeoJSON
Fossils
In the Darvaz Range and in the basin of the Fedchenko glacier in the Vanchdarin Fm (in that part where the effusives are absent) M.I. Shabalkin, A.K. Kafarsky, and I.V. Pyzhiyanov discovered Pseudofusulina cf. fusiformis (Schellw. et Dyhr.), Parafusulina ex gr. granum-avenae Schub., Monodiexodina ex gr. ferganica (M.-Maclay), Rugosofusulina ex gr. alpina (Schellw.), and others. These fusulinids belong to the Ulyuk horizon of the Lower Permian. Due to the rare finds of organic remains (not throughout the suite section), as well as their poor preservation.
Age
Depositional setting
Additional Information
A.K. Kafarsky and I.V. Pyzhiyanov conditionally equate that part of the Vanchdara suite where greenstone effusives are present with analogous carboniferous volcanics of the Darvaz and Mukhsuy districts. Thus, they significantly alter the scope of the Vanchdara suite, initially proposed by M.I. Shabalkin.