安徽洪镇地区董岭群片麻岩独居石SIMS U-Th-Pb定年

发布时间：2018-05-26 17:11

本文选题：董岭群 + 独居石SIMS　；参考：《大地构造与成矿学》2017年04期

【摘要】：本文报道了安徽洪镇地区董岭群片麻岩中高精度的独居石SIMS U-Th-Pb定年结果,以~(207)Pb含量为基准对普通Pb进行校正后得到~(206)Pb/~(238)U的加权平均年龄为128.4±0.7 Ma(MSWD=1.6),~(208)Pb/~(232)Th年龄的加权平均值为128.6±0.4 Ma(MSWD=1.4)。作者认为独居石的SIMS U-Th-Pb年龄(128.4±0.7 Ma)代表了董岭群片麻岩的前进变质年龄。综合区域地质资料,提出董岭群片麻岩为新元古代沉积物在中生代经岩浆热动力接触变质的产物。这一发现不仅否定了前人提出的董岭群为前寒武纪区域变质地体的观点,而且否定了这一地区的"洪镇变质核杂岩",对进一步研究中国东部零星出露的中高级片麻岩的大地构造属性和构造演化具有借鉴意义。
[Abstract]:This paper reports the high accuracy SIMS U-Th-Pb dating results of monazite in the Dongling gneiss in Hongzhen area, Anhui Province. The weighted average age of 128.4 卤0.7 mg / L Pb / P / 238U is 128.4 卤0.7mg / ml / L ~ (1.6) mg / L ~ (2 +) ~ 2 ~ (2 +) T ~ (-1) ~ (-1) ~ (-1) ~ (128.6 卤0.4) SIMS U-Th-Pb ~ (-1) ~ (-1) ~ (-1) ~ (-1) ~ (-1) ~ (-1) ~ (-1) ~ (-1) ~ (-1) ~ (-1). The authors consider that the SIMS U-Th-Pb age of monazite (128.4 卤0.7 Ma) represents the progressive metamorphic age of the Dongling group gneiss. Based on the regional geological data, it is suggested that the Dongling group gneiss is the product of the metamorphism of Neoproterozoic sediments in the Mesozoic by thermal contact with magma. This discovery not only negates the former view that Dong Ling Group is a Precambrian regional metamorphic terrane, It also negates the "Hongzhen metamorphic core complex" in this area, which is useful for the further study of the tectonic properties and tectonic evolution of the middle and high grade gneiss sporadically exposed in eastern China.
【作者单位】：中国冶金地质总局山东局测试中心;中国地质大学(武汉)地球科学学院;中国科学院广州地球化学研究所同位素地球化学国家重点实验室;
【基金】：中国科学院知识创新项目(KZCX2YW128,KZCX1YW151) 国家自然科学基金(41173037)联合资助
【分类号】：P588.345;P597.3

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