Zygar Fm
Type Locality and Naming
It was distinguished by N. G. Vlasov (Vlasov and Miklukho-Maklai, 1959).
Synonym: Zygarskaya suite, Зыrарская свита, Ulyk and Kubergetin horizons
Reference section:
Lithology and Thickness
It belongs to Ulyk and Kubergetin horizons. It is composed of frequently alternating dark gray and greenish-gray polymictic (graywacke) sandstones and claystones, containing interbeds and lenses of dark gray limestones and various gravely conglomerates. In some sections, conglomerates make up to 30% of the suite's volume. The clasts in them are predominantly greenstone effusive-clastic rocks of the lower Carboniferous. The thickness of the suite is 400-1600 m.
The lower parts of the Zygar Fm are sometimes (v. Shagon) replaced by layered gray limestones of the upper sub-suite of the Sebisurkh Fm with a thickness of 0-200 m.
The middle and upper parts of the Zygar Fm are sometimes (r. Vozgina) replaced by light gray massive and layered limestones of the lower sub-suite of the Safetdaron Fm with a thickness of 0-1200 m
Relationships and Distribution
Lower contact
The Zygar Fm conformably overlays the Khorezhska Fm or the lower sub-suite of the Sebisurkh Fm, which belong to the Karachatyrsky horizon. Occasionally, the Zygar Fm conformably rests upon the limestones of the upper sub-suite of the Sebisurkh Fm, replacing its lower parts.
Upper contact
The Zygar Fm is covered by terrigenous rocks of the Chelamchin Fm, or by limestones of the upper sub-suite of the Safetdaron Fm.
Regional extent
GeoJSON
Fossils
In it, remains of fusulinids of the Uluk horizon and Early Permian (Artinskian) corals Darvasites ex gr. contractus Schellw. et Dyhr., Pseudofusulina Exigua Schellw. et Dyhr., Ps. vulgaris Schellw. et Dyhr., Chusenella cf. globulariformis (Dutk.), Yokoyamaella yokoyamai Oz., Pseudobradyphyllum nikitini Dobr., etc. O. G. Tuman'skaya identified ammonoid remains from here that, in her view, are similar to late Artinskian ammonites from the Urals: Propinacoceras bornemani Toum., Prosicanites edelsteini Toum., Artinskia aff. artiensis Grün. var. timorensis Han., Popanoceras laghuseni Karp., Aghaticeras sp.
The lower parts of the Zygar Fm, in them, remains of the Karachatyrsko-Uluk fuzulines and corals have been found: Schwagerina sp., Pseudoschwagerina sp., Pseudofusulina Exigua Schellw. et Dyhr., Ps. kraffti Schellw. et Dyhr., Ps. fusiformis Schellw. et Dyhr., Chusenella globularioormis (Dutk.), Caninophyllum ex gr. sophiae Her., and others.
The middle and upper parts of the Zygar Fm, containing remains of fusulines close to those mentioned above: Robustoschwagerina tumida Lich., Pseudofusulina kuznetcovi M.--Maclay, Ps. Exigua Schellw. et Dyhr., Ps. longitermina Chen.
Age
Depositional setting
Additional Information