Damamat Fm
Type Locality and Naming
Includes in Akbaital-Rangkul region. They characterize the Kokuybelsky type of Jurassic sections. In the literature, they are known as the Damamat suite (дамаматской свиты) (Dronov, Leven, 1961).
Synonym: Damamat suite, дамаматской свиты
Reference section:
Lithology and Thickness
It is composed at the bottom of gray and varicolored sandy marls and clayey limestones (80-120 m), at the top - gray coarse-and giant-bedded, in places massive limestones, partly reef (600-800 m); in the cap of the suite in the Yazgulem Range, a banded package (20-80 m) of alternation of carbonate and terrigenous rocks is distinguished. The total thickness of the suite is 700 - 1000 m.
In the Central Pamir type of Jurassic sections, the age equivalent of the Damamat Fm is the Chatagai Fm of carbonate and terrigenous rocks, exposed in the area of the Soviet Officers Peak. Thickness 100-300.
In the southern part of the Sarykol district of the Northern Pamir, analogs of the Damamat Fm were found by G. P. Kreydenkov, V. A. Raspopin, and A. Ya. Frolenkova (1970) to the north of the Akbaytal pass in the interfluve of the Northern Akbaytal and Tuyun-su. These are interbedded dolomites, limestones, sandstones, claystones, conglomerates, and gypsums with a thickness of 140 m.
Relationships and Distribution
Lower contact
They conformably overlie on the Lower Jurassic - Bajocian layers Kokuybel Fm (кокуйбельской сRите). In the Central Pamir type of Jurassic sections, it lies conformably on the conditionally Lower-Middle Jurassic deposits of this area (Murkallin Fm) (муркаллинс-кой свите). In the southern part of the Sarykol district of the Northern Pamir, they lie with a sharp angular discordance on the shales of the Cheloktekinsky Fm (челоктекинской Свиты), conditionally Middle-Late Ordovician.
Upper contact
It is overlain conformably (and in some areas with erosion) by the conditionally Lower Cretaceous red strata of the Yazgulem Ridge and the watershed area of the Kokuybel-Tanyamas rivers. In the Central Pamir type of Jurassic sections, the overlying deposits are absent here. In the southern part of the Sarykol district of the Northern Pamir, visibly conformably overlain by red-colored sandstones and conglomerates of the Lower Cretaceous.
Regional extent
It is widespread in the Central Pamir, in the sections of the kokuybelsky, Bartang-Pyanj, and Central Uzkol types. In the Central Pamir type of Jurassic sections, the age equivalent of the Damamat Fm is the Chatagai Fm. In the southern part of the Sarykol district of the Northern Pamir, analogs of the Damamat suite were found by G. P. Kreydenkov, V. A. Raspopin, and A. Ya. Frolenkova (1970) to the north of the Akbaytal pass in the interfluve of the Northern Akbaytal and Tuyun-su.
GeoJSON
Fossils
The lower part of the suite is rich in organic remains, containing a complex of Bathonian-Kimmeridgian pelecypods and ammonites. Pelecypods -- Inoperna sowerbyi Orb., Plagiostoma cardiforme Sow., Myopholas acuticostata Sow., Modiola cf. imbricata Sow., and others; ammonites - Macrocephalites cf. triangularis Waag. The upper part of the suite contains rare remains of Late Jurassic pelecypods and gastropods. Pelecypods - Chlamys cf. midas Damon, Diceras (Plesiodiceras) ci. wisicinum Thurm.; gastropods Nerinea cf. ursicinensis Thurm., Psetidorinea clio Orb., Nerinella planiuscula Lor.
In the southern part of the Sarykol district of the Northern Pamir, in them, Bathonian-Kimmeridgian pelecypods were found: Exogyra cf. nana Sow., Modiolus gibbosus Sow., M. tumidus Morris et Lycett, Mytilus madagascarensis Newt., Cypricardia cf. acuticarinata Terq. et Jourdy, Thracia Amygdaloidea Lycett, Chlamys aff. valleculata Andreeva, Chl. aff. aksaica Andreeva, Chl. cf. dewalquei Oppel, Isodonta triangularis (Phill.), close to those found in the Damamat Fm (дамаматской свите) of the Central Pamir.
Age
Depositional setting
Additional Information