Paleomagnetism of the Ulkan trough (Southeastern Siberian Craton)

摘要

The first results of the paleomagnetic study of one of the key Paleoproterozoic objects of the Aldan-Stanovoy Shield (the Ulkan trough) in the Bilyakchan-Ulkan volcanoplutonic belt are presented. The volcanosedimentary rocks of the Elgetei Formation and the granites of the Ulkan Complex were studied. According to these data and their comparison with the apparent Paleoproterozoic polar wandering path in the Angara-Anabar province, the Ulkan trough was (1) located during the timing of the studied rocks at 18°-26° S and (2) subjected to rotation (relative to the Angara-Anabar block) at 70° ± 8° in the time interval of 1732-1720 Ma ago. Based on the combined interpretation of the paleomagnetic, geochronological, and geochemical data published previously, a paleogeodynamic model is proposed. According to this model, the Aldan-Stanovoy and Angara-Anabar provinces of the Siberian Craton became a single rigid block about 1720 Ma ago.