THE DISCOVERY AND PRELIMINARY STUDY OF GRANULITE FACIES ROCKS IN THE WEIHAI RUSHAN REGION,EASTERN SHANDONG

The Weihai Rushan granulite belt is the northwestern marginal zone of the northeastern section of the Subei Jiaonan tectonic melange zone.The granulite bodies have no roots and occur mainly as lenses.The typical mineral assemblages are Cpx+Gr+Pl+Q,Cpx+Opx+Gr+Pl and Opx+Gr+Cpx.The clinopyroxenes contain 2.50% 8.79% jadeite and the garnets contain 14.47% 35.36% pyrope.The granulite facies rocks were formed at P=7.91 10.70×10 8Pa,T=717 807℃,a geothermal gradient of approximately 21 25℃/km and burial depths of roughly 29 39 km;so the rocks belong to middle pressure granulite facies.The age of the peak metamorphism is about （1913±9）Ma.