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苏北高压变质带位于苏鲁超高压变质带东南缘,露头多为绿片岩相的中—晚元古代云台岩群,典型的蓝片岩仅见于灌云县杨集的钻孔岩心中。本文通过拉曼光谱研究,在连云港地区的绿片岩内石榴石中发现文石(CaCO3)包裹体。文石呈细小包裹体残留于细粒半自形石榴石斑晶中。这些石榴石作为低扩散的刚性矿物,经历了多期变质变形作用,变质反应证据保存在石榴石的成分环带及包体矿物组合中。文石包裹体的存在证明苏北高压变质带北部的、即本区出露的这套岩系是早期经历了高压变质作用、晚期又叠加了绿片岩相变质作用的高压变质地体。
The Northern Jiangsu high-pressure metamorphic belt is located in the southeastern margin of the Sulu UHP metamorphic belt. The Meso-Neoproterozoic Yuntai Rock Group is mostly outcropping of greenschist facies. The typical blue schist is found only in the borehole core of Yangji in Guanyun County. In this paper, aragonite (CaCO3) inclusions are found in the garnet within the green schist in Lianyungang through Raman spectroscopy. Aragonite small inclusions remain in fine semi-self-shaped garnet phenocrysts. These garnets, as low-diffusion rigid minerals, have undergone multi-stage metamorphism and deformation. The evidence of metamorphic reaction is preserved in the compositional zoning of garnet and the mineral assemblage of inclusions. The existence of aragonite inclusions proves that the rock series exposed in the northern part of the northern Jiangsu high-pressure metamorphic belt, that is, the area exposed in this area are high-pressure metamorphic terranes that experienced high-pressure metamorphism in the early stage and green-schist facies metamorphism in the late stage.