New mineral evidence of high-pressure metamorphism of the Subei high-pressure belt-Aragonite inclusions in garnet from greenschist

The Subei high-pressure(HP )metamorphic belt lies on the southeastern margin of the Sulu ul-trahigh-pressure(UHP )metamorphic belt,northern Jiangsu.Most of its outcrops consist of greenschist-fa-cies rocks of the Meso-to Neoproterozoic Yuntai Group-complex.In this belt,however,the typical blueschist is only found in drill cores from Yangji Town ,Guanyun County,northern Jiangsu.The laser Raman(LRM)spectrum shows that there occur micron-sized aragonite(CaCO 3 )inclusions in fine-grained subhedral garnet phenocrysts from greenschist of the group-complex in Lianyungang,northern Jiangsu.These garnets as a low-diffuse rigid mineral have undergone multi-stage deformation and metamorphism.The ev-idence of the metamorphism is preserved in the compositional zoning of garnet and the inclusion mineral assemblage.The appearance of aragonite inclusions indicates that the greenschist-facies rocks in the northern part of the Subei HP metamorphic belt,i.e.the outcrops in the study area,are part of a HP terrane which was overprinted by greenschist facies metamorphism in the late stage.