Abstract
Abstract The new data on the tectonic settings and sedimentational circumstances of the Middle-Late Cambrian deposits of the southern part of the North Kara terrane, presented in our research, the data induced from the studies of clastic rocks in the basement metaterrigeneous complexes of Troynoy island (archipelago Izvestia CEC) and the northern part of Bolshevik island (archipelago Severnaya Zemlya). The sandstones of both regions are similar in the lithic wacke composition and contain the same groups of rocks fragments. Clastic zircons and Cr-spinels from sandstones of both regions have the same Zr/Hf and TiO2/Al2O3 ratios, respectively.
 The similarity of even-aged sediments from both regions can be explained by their accumulation due to the demolition of detrital material from a single source eroded area, which is a segment of the accretionary uplift of the Timan‒Severnaya Zemlya orogenic belt, with the newly formed continental Neoproterozoic-Cambrian crust. The low and medium-grade metamorphosed terrigeneous complexes dominated in the structure of the source area. Presence of volcanic and intrusive complexes in the source area is marked by clastic Cr-spinels with geochemical signatures of volcanic arc and suprasubductional ophiolites origin. By the beginning of the Ordovician, the Middle Late Cambrian sediments were also crushed, metamorphosed, and included in the structure of the Timan‒ Severnaya Zemlya orogenic belt.
 Peculiarities of petrographic and grain-size composition and sorting of the sandstones from the north of Bolshevik island are more typical for the sediments of gravity turbidite flows, in deep or relatively deep water conditions. The deposits of Troynoy island could be formed at shallow and coastal-marine environments.
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