ISSN 1009-6248CN 61-1149/P 双月刊

主管单位:中国地质调查局

主办单位:中国地质调查局西安地质调查中心
中国地质学会

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    华北克拉通怀安县西洋河地区高压基性麻粒岩锆石U-Pb同位素年龄及地球化学特征

    Geochemical Characteristics and Zircon U-Pb Isotope Age of the High-pressure Basic Granulite in the Xiyanghe Area of the North China Craton

    • 摘要: 华北中北部出露的高压麻粒岩对研究华北克拉通新太古代—古元古代构造演化具有重要意义。笔者通过对怀安县西洋河地区怀安杂岩中新发现的高压基性麻粒岩的地质、地球化学特征、变质作用及锆石U-Pb同位素年龄研究和讨论,确定研究区高压基性麻粒岩原岩为基性岩浆源(辉长岩或玄武岩),具有MORB型玄武岩地球化学特征,形成年龄早于2 162 Ma;岩石主要经历了峰期高压麻粒岩相变质作用和后期退变质作用的改造;峰期平均变质年龄为1 925 Ma,后期退变质年龄为1 865 Ma;反映了新太古代-古元古代碰撞造山过程,为研究华北克拉通构造演化提供了新的证据。

       

      Abstract: The high-pressure granulite exposed in the north-central part of north China is of great significance to the study of the Neo-Archaean-Palaeoproterozoic structural evolution of the north China craton. This thesis researched and discussed the geological, geochemical, metamorphic and U-Pb isotope ages of zircon in high pressure basic granulite, which newly discovered in the huaian complex in the xiyanghe area of huaian county. Though it, we concluded that the high pressure basic granulite was determined to be a basic magmatic source(gabbro or basalt), which has the geochemical characteristics of MORB type basalt, and its formation age was earlier than 2 162Ma. The rock has mainly undergone the geological transformation of high-pressure granulite facies metamorphism in the peak period and metamorphism in the later period, and with metamorphic ages of 1 925 Ma and 1865 Ma respectively, which reflected the Neoarchean-Palaeoproterozoic collision orogenic process and provided new evidence for studying the structural evolution of the North China Craton.

       

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