【摘要】 中山片麻岩是一套含石榴石的淡色长英质片麻岩，主要出露在东南极拉斯曼丘陵的中山站附近。新的LA-ICP-MS U-Pb锆石年龄数据分析结果表明：中山片麻岩原岩的物源区主要来源于中元古代晚期大陆地壳，原岩的沉积作用发生在1200～944Ma之间；在格林维尔期(～944Ma)麻粒岩相变质作用过程中，这些沉积岩原岩经深熔作用形成淡色花岗岩；随后在泛非期(～550Ma)再次经历了高级变质作用。岩石学、全岩地球化学分析结果表明，中山片麻岩主体属于一套过铝质高钾钙碱性岩石系列，具有类似S型花岗岩的地球化学特征，结合微量元素Nb、Ta和Ti亏损，富集Rb、Th和K大离子亲石元素的特征，反映其源区很可能是以杂砂岩为主混合少量泥质岩的沉积岩，沉积物源区可能来自与俯冲有关的大陆岛弧地区，也就是说拉斯曼丘陵在1000Ma前处于印度-南极克拉通边缘的成熟的活动大陆边缘的构造环境。更多还原

【Abstract】 The Zhongshan gneiss is a set of garnet-bearing felsic leucogneisses outcropped near Zhongshan Station in the Larsemann Hills of East Antarctica. New LA-ICP-MS U-Pb zircon ages shed new light on the geological processes of the Zhongshan gneiss as follows: its protoliths were sedimentary rocks formed between 1200Ma and 944Ma, whose source materials were derived from the Late Mesoproterozoic continental crust; these sedimentary protoliths were then partially melted to have formed leucogranites during granulite facies metamorphism at ca. 944Ma; subsequently, the leucogranites underwent high-grade metamorphism at ca. 550Ma. All results of petrology and whole-rock geochemistry show that the Zhongshan gneiss is peraluminous high-K calc-alkaline rocks, which have similarities to the geochemical characteristics of S-type granitoids, suggesting possible derivation from partial melting of metamorphic sandstones mixed with a small number of argillaceous rocks. The depletion of Nb, Ta and Ti elements in company with the enrichment of large ion lithophilic elements(Rb, Th and K) indicate that the precursors of the Zhongshan gneiss probably originated from continental island arc regions associated with subduction. Accordingly, the Larsemann Hills probably represent a contiguous terrane located inboard of a ca.1000Ma continental margin that was active along the leading edge of the Indo-Antarctic craton.更多还原