First record of Late Pennsylvanian fusulinids from the North Tianshan belt, NW China

Abstract

A noteworthy late Pennsylvanian fusulinid fauna is for the first time reported from the Qi'eshan Formation in the Eastern Tianshan, NW China. From three main outcrop sections, 19 species of six genera are identified and illustrated, among which several index taxa are described in detail. The present fusulinids are assigned to the middle Kasimovian to early Gzhelian in age, representing the youngest fusulinid fauna in northern Xinjiang up to now, which constrains the age of the Qi'eshan Formation up to the early Gzhelian. Palaeobiogeographically, the fusulinid fauna in the Eastern Tianshan was closely related to the populations from Central Asia (e.g., southern Fergana, the Alay Mountains and Darvaz) of the western Palaeotethyan Subprovince, and kept exchanging with those from the Eastern European Platform of Ural Province, given the common, particularly endemic species. The characteristic species include Montiparus ex gr. sinuosus alaicus, Rauserites rossicus, Schwageriniformis fusiformis, Triticites acutus, Triticites arcticus, and Triticites arcticus cybaeus. This palaeobiogeographic affinity suggests that the close of timing of the North Tianshan Ocean was later than the Early Gzhelian, and that the southern Urals and western Palaeotethys shared a common fusulinid fauna during this period.