Isotope-Geochronological Timing of Metamorphic Events in the Boundary Zone between the Aldan Shield and the Dzhugdzhuro-Stanovoi Folded Area

摘要

Previous studies demonstrated [1-3] that age estimation of leucosomes of anatectic and diatectic mig-matites and products of granitization (granite gneiss) is an effective way to understand the sequence of the formation of polymetamorphic complexes, because their relative sequence is easily established on the base of simple, uniquely inter preted geological observations. Migmatites of the Stanovoi complex in the zone of direct junction between the Dzhugdzhuro-Stanovoi Folded Area (DSFA) and the Aldan Shield (AS), which were investigated in the section along the Malyi BAM in the area of Nagornyi Village and Kholodni-kan Pass, are the object of this study. We already studied the relations between the Aldan and Stanovoi complexes in the early 1960s [4]. It was revealed that over-thrust-sheet structure was developed in this zone and the tectonic plate moderately dips to the south. They are deformed in linear open or isoclinal folds oriented in the latitudal direction parallel to the whole junction zone.