Medium-low pressure metamorphism and P-T paths in Danba domain, Sichuan province of the western China
四川丹巴地区中低压变质作用及P-T轨迹

Danba Domain is in the convergent junction of North China block, Yangtze block and Qiangtang block. There are Medium pressure barrovian type metamorphic zones and low pressure Buchan metamorohic sequences. The study is of great theoretic and dynamic significance in understanding the formation of Songpan - Ganzi orogen and the crust evolution. On the basis of geothermbarometry, we set up P-T paths and calculated the geothermal gradient for each of the metamorphic zones. The results show that both the barrovian and the Buchan metamorphic rocks have clockwise P-T paths but there are difference in geothermal gradient. Combined with the field, mineral assemblages and metamorphic reactions, we think that there do exist barrovian and Buchan zones in Danba domain and that different geothermal gradient may indicate various tectonic settings.