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中国苏鲁高压-超高压变质地体由2个不同时代的变质基底组成.南苏鲁(临沭-连云港地区)中不同类型高压-超高压变质岩石的原岩形成于由大陆玄武质岩石、辉长岩、表壳岩和花岗岩组成的被动大陆边缘拉伸构造环境.研究表明南苏鲁高压-超高压变质岩石的原岩所代表的花岗岩浆和基性岩浆作用为罗迪尼亚超大陆形成后的新元古代(780-700Ma)裂解事件的响应.北苏鲁(青岛-威海)超高压变质地区的花岗质片麻岩锆石SHRIMPU-Pb定年表明,变质基底的年龄是2400Ma(或>2400Ma),并经历了1800-1700Ma和-200Ma的变质事件,研究表明苏鲁高压-超高压变质地体由2个不同时代变质基底组成,北苏鲁的变质基底属于北中国板块胶辽朝地块的一部分,形成时代比南苏鲁基底老得多,其与南苏鲁地块之间的界限位于五莲以北到海阳所以南一线.由于在北苏鲁含柯石英的透辉石石英岩锆石SHRIMPU-Pb定年获得精确超高压峰期变质年龄为(234.1±4.2)Ma,退变质年龄为(218.2±1.5)Ma,表明南、北苏鲁2个不同时代基底地块同时经历了超高压变质作用.根据上述事实,提出苏鲁高压-超高压变质地体的陆-陆碰撞俯冲剥蚀新模式,即扬子板片在240-220Ma的深俯冲作用中拽动上部胶辽朝板片的-部分老变质基底岩石向下俯冲至大于100km的深度,并形成楔形俯冲剥蚀体,之后又与南苏鲁俯冲板片一起快速折返上来,使胶辽朝地块的楔形俯冲剥蚀体经历了高压-超高压变质和折返退变质作用
The UHP-UHP metamorphic terrane in China is composed of two metamorphic basalts of different ages.The original rocks of different types of high-pressure metamorphic rocks in South Sulu (Linshu-Lianyungang area) Gabbro, granite.The study shows that the granite magma and basic magmatism represented by the original rocks of the South Sulu high-pressure-ultrahigh-pressure metamorphic rock belong to the continental boundary of the Rodinian supercontinent The formation of the Neoproterozoic (780-700 Ma) cleavage event response SHRIMPU-Pb dating of granitic gneiss in the UHP metamorphic area of the North Sulu (Qingdao-Weihai) indicates that the age of the metamorphic basement is 2400 Ma Or> 2400Ma), and experienced metamorphic events of 1800-1700Ma and -200Ma. The study shows that the high-pressure metamorphic terrane of the Sulu region consists of two metamorphic basalts of different ages, and the metamorphic basement of the North Sulu Belong to the northern China plate As part of the plot, the age of the formation was much older than that of the South Sulu base, and the boundary between it and the South Sulu massif lies south of Wulian to the south of Haiyang, Pyroxene quartz zircon SHRIMPU-Pb dating (234.1 ± 4.2) Ma and degenerated age (218.2 ± 1.5) Ma, respectively, indicating that the basement blocks of two different epochs of South and North Sulu experienced the UHP metamorphism at the same time.According to the above In fact, a new model of continent-continent collision subduction of the Sulu high-pressure metamorphic terrane is proposed. In the deep subduction of 240-220Ma, the Yangtze plate pushes a part of the old metamorphic basement rocks Down to a depth of more than 100 km and formed a wedge-shaped subduction body, followed by rapid reentry with the South Sulu subducting plate. The wedge-shaped subduction body of the Jiaoliao-DPRK experienced high pressure-high pressure metamorphism and reentry Degeneration effect