Alakagar Fm

It is distinguished by N. G. Vlasov (1958, 1961).

Synonym: Alakagar suite, Аликаrарская свита

Reference section:

It is mainly represented by gray-green argillaceous clays similar to claystones with rare interlayers of sandstones, gravelites, and conglomerates with a thickness of 3 to 12 m. In all varieties of the rocks, there is an admixture of volcanic (ash and lapilli) material. The thickness of the suite reaches 190 m.

Paleontological remains are noted throughout the section of the suite. Ammonites have been identified (determinations by A. A. Shevyrev and B. K. Kushlin): Meekoceras aff. gracilitatis White, M. aff. pseudoplanulatum Krafft, Eukashmirites acutangulatus (Welter), E. aff. subarmatus (Diener), Eukashmirites sp., Pseudoceltites aff. multiplicatus (Waagen), Owenites koeneni Hyatt et Smith, Flemingites sp., Kashmirites aff. armatus Waagen, K. contortus Ast. All these forms are characteristic of the lower part of the Olenekian stage, they come from the species zone of Meekocenas gracilitatis, i.e., from the lower part of the Owenitid zone. The complex of ammonites is quite representative and diverse. Most of the named forms are found throughout the section of the Alakagar suite, and the zonal species Meekoceras gracilitatis has been identified both at the base of the formation and at its top.

The complex of bivalve mollusks collected from the Alakagar suite is close to the one mentioned above from the underlying deposits, differing from it only by the appearance of abundant Velopecten alberti (Goldf.). Together with the fauna, throughout the section of the suite, numerous fragments of plants of the genus Pleiromeia have been collected, which according to I. A. Dobrushkina is a new species.