Mesozoic age of the last episode of high-temperature metamorphism of the Sutam block of the Stanovoi suture

摘要

The U-Pb (zircon) age of 250 +/- 1 Ma was determined for differentiated gabbro-monzonite intrusions, which were formed prior to metamorphism of high-temperature amphibolite facies of high pressures in the southeastern part of the Sutam block of the Stanovoi suture. These data indicate that this episode of metamorphism belongs to the Mesozoic stage of evolution of the Stanovoi suture rather than to the Early Precambrian, as was suggested before. It most likely corresponds to the age of the last episode of the high-temperature metamorphism of amphibolite facies (140 Ma), which is manifested within the Dzhugdzhur-Stanovoi superterrane of the Central Asian foldbelt adjacent from the south to the Stanovoi suture and is caused by collision of the Dzhugdzhur-Stanovoi superterrane and the epi-Paleozoic Amur microcontinent during the closure of the Mongol-Okhotsk oceanic basin.