PALEOMAGNETISM OF VOLCANOGENIC COMPLEXES FROM THE PREDIVINSK TERRANE OF THE YENISEI RIDGE: GEODYNAMIC IMPLICATIONS

Abstract

Several recent publications demonstrate that the marginal zone of the Yenisei Ridge incorporates a belt of Neoproterozoic island-arc and ophiolitic rock complexes thrust over sedimentary-metamorphic sequences of the passive margin of the Siberian Craton. The Predivinsk terrane, a constituent of the southern part of the belt), is composed of differentiated calc-alkaline volcanics that are metamorphosed under conditions of the greenschist facies that are typical of island arcs. The age and geodynamic nature of the volcanics in the Predivinsk terrane make them highly attractive for paleomagnetic studies aimed at reconstruction of the paleogeographic position of the terrane in the structure of the southwestern Siberian paleocontinent margin. The Predivinsk island-arc terrane 640 Ma ago was located immediately near the craton margin. Hence, the calculated paleomagnetic pole can be used, in first approximation, for reconstructing the Neoproterozoic segment of the Siberian apparent polar worker.