北苏鲁超高压变质带前寒武纪基底研究新进展

北苏鲁超高压变质带位于胶东牟平—即墨断裂以东的地区,其前寒武纪基底以出露新元古代的双峰式火成岩为主要特征,其主要岩石组合包括大量花岗片麻岩以及少量变(超)基性岩(榴辉岩)、变沉积岩。对花岗片麻岩、变质(超)基性岩的岩石组合、地球化学、锆石U-Pb和Lu-Hf同位素的研究表明,北苏鲁存在新太古代—古元古代的残留地壳,经历了1.8～2.2 Ga期间的岩浆-火山-变质事件;新元古代中期(0.72～0.80 Ga)与Rodinia超大陆的裂解相关的岩浆活动促使地壳的生长和再造,形成了北苏鲁的前寒武纪基底的主体;北苏鲁和苏鲁—大别造山带一样,其前寒武纪基底是扬子板块北缘的一部分,苏鲁造山带的西北边界是五莲—烟台断裂带。

Main Progresses in the Study of Precambrian Basement of the North Sulu Ultra-high Pressure Metamorphic Belt, Eastern China

The north Sulu ultra-high pressure(UHP) metamorphic belt which is located at the eastern Muping-Jimo fault in eastern Shandong Peninsula is mainly characterized by Neoproterozoic bimodal igneous rocks.And its assemblages include a large number of granitic gneiss and a small amount of ultra basic/basic metamorphic rocks and metasedimentary rocks.The previous research of geochemical,zircon U-Pb,Lu-Hf isotope data revealed the geologic succession of the north Sulu UHP terrane.The Neoarchean-Paleoproterozoic ancient crust was remained and its initial crust evolution might start from Neoarchean or even earlier,then it undergone a series of magma-volcano-metamorphic events during 1.8-2.2 Ga.The bimodal magmatism,which caused by the rifting of the Rodinia Supercontinent at mid-Neoproterozoic(0.7-0.8 Ga) reworked the ancient and juvenile crust.As the same to the Sulu-Dabie orogen terrane,some characteristics of the Precambrian basement of the north Sulu UHP terrane are corresponding to Yangtze Block,and its northwestern boundary to the North China Block may be located along the Wulian-Yantai fault.