First Evidence for the Presence of the Upper Carboniferous Deposits on the Tuora-Sis Uplift of the Lower Reaches of the Lena River, Northeast Russia

A vertical sequence of brachiopods was revealed at the base of the Verkhoyanian terrigenous complex of the Tit-Ary section in the northern part of the Tuora-Sis uplift of the lower reaches of the Lena River. As a result of the study of these brachiopods, it was established that in the indicated section, the Upper Cambrian dolomites are overlain by Gzhelian and Asselian deposits, characterized by brachiopods of the Jakutoproductus protoverkhoyanicus and Jakutoproductus verkhoyanicus biostratigraphic zones. This is the first proven fact of the presence of Upper Carboniferous deposits in the area. It is concluded that within the Tuora-Sis uplift from south to north, the upper age limit of the unconformity between the Cambrian and the Upper Paleozoic is growing older, while the base of the Verkhoyanian terrigenous complex is built up by the Permian basal beds and the Gzhelian deposits of the Upper Pennsylvanian. The Tit-Ary section is the first of those established in the lower reaches of the Lena River, with exposed boundary Carboniferous–Permian beds.