Cambrian paleomagnetism in the Bateni Ridge; evolution of the Kuznetsk Alatau island arc (southern siberia)
Cambrian paleomagnetism in the Bateni Ridge; evolution of the Kuznetsk Alatau island arc (southern siberia)
Russian Geology and Geophysics (January 2012) 53 (1): 37-50
We present paleomagnetic data on the Cambrian volcanosedimentary complexes of the Bateni Ridge, which correspond to the evolution of the Kuznetsk Alatau island arc. The paleomagnetic poles which served as the basis for the apparent polar-wander path (APWP) were determined. The paleomagnetic data were compared with those on the Cambrian poles for other fragments of the Kuznetsk Alatau island arc. For example, the APWP of the Bateni fragment corresponds to that of the Kiya (Martaiga) fragment of the eastern slope of the Kuznetsk Alatau. The distribution of the paleomagnetic poles suggests that the relative drift of the Kuznetsk Alatau arc fragments and the entire island arc system resulted from large-amplitude strike-slips. In the Cambrian, this paleoarc moved from approximately 10 degrees N to approximately 10 degrees S and rotated more than 50 degrees clockwise. In the paleomagnetic record, its accretion is reflected in the coincidence of the Late Cambrian-Early Ordovician poles on the eastern slope of the Kuznetsk Alatau with one another and the coeval poles for the Siberian craton. This coincidence also suggests that the general structure of the present Kuznetsk Alatau formed as early as the Early Caledonian. Nevertheless, the differences in the position of the poles on the western and eastern slopes of the Kuznetsk Alatau suggest that strike-slip activity along the Kuznetsk-Altai deep fault (the major one in the region) continued in the Late Paleozoic and, probably, in the Mesozoic.