Vasmiukh Fm
Type Locality and Naming
It is distinguished by N. G. Vlasov (1958, 1961).
Synonym: Vasmiukh suite, Васмикухская свита
Reference section:
Lithology and Thickness
The Vasmiukh suite is predominantly composed of reddish-gray and gray-violet sandstones up to 800-1100 m thick, known from studies by A. Krafft, Ya. S. Edel'shtein, V. I. Popov, and other geologists. It is clearly subdivided into two sub-suites.
The lower sub-suite is represented by red and gray-violet coarse-grained greywacke cross-bedded sandstones with layers of gravels and conglomerates. The role of the latter in the section and in area is variable. In the southern sections, the coarse-grained rocks predominate over the sandstones. The rocks constantly contain a mixture of volcanic material. The thickness of the layer is 140-300 m.
The upper sub-suite consists mainly of marine brownish to reddish-gray fine-grained greywacke sandstones. Its thickness is 700-900 m. A distinctive feature of the layer is the fine rhythmicity of the flyschoid type. Micro-rhythms are formed by a set of lithological varieties of rocks, with a regular alternation from medium- and coarse-grained sandstones to claystone-like clays. Throughout the sub-suite, there are thin (1.2-3.8 m) horizons of volcanics (dacite-liparite tuffs). The rocks are enriched to varying degrees with ash, and less commonly with lapilli material.
Relationships and Distribution
Lower contact
lies on an eroded surface of the limestone of the Chapsay Fm of the Pamir horizon of the Permian with visible conformity, sometimes with slight angular unconformity.
Upper contact
It is overlain by the Alakagar Fm conformably.
Regional extent
It is widespread in the southwestern part of the Darvaz region.
GeoJSON
Fossils
Organic remains were not found in the lower sub-suite of the Vasmiukh Fm.
In the upper sub-suite, ammonites Koninckites ensanus (Krafft), K. disciformis (Krafft), K. cf. spitiensis (Krafft), K. discus (Waagen), Koninckites sp., "Meekoceras" planulatum (Koninck), Flemingites sp., Gyrophiceras aff. planorbe (Waagen), Ambites aff. discus Waagen, Prionolobus aff. rotundatus Waagen, Kingites aff. varaha Diener, and others, have been identified throughout the section by us, which according to A. A. Shevyrev are characteristic of the gyrinoceratid (upper) zone of the Induan horizon. Bivalve mollusks (determined by B. K. Kushlin) are more diverse and numerous: Eumorphotis telleri Bitt., E. venetiana Hauer, E. multiformis Bitt., E. inaequicostata (Ben.), E. tenuistriata Bitt., E. multiformis var. rara Kipar., Myophoria ovata Goldf., M. laevigata (Zieth.), Anodontophora canalensis (Cat.), A. fassaensis Wissm., etc., which also correspond to the Induan horizon.
Age
Depositional setting
Additional Information