Nature of magmatism and sedimentation at a Columbia active margin: Insights from combined U–Pb and Lu–Hf isotope data of detrital zircons from NW India
Nature of magmatism and sedimentation at a Columbia active margin: Insights from combined U–Pb and Lu–Hf isotope data of detrital zircons from NW India
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DOI：
10.1016/j.gr.2012.07.008
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发表时间：
2013-04
影响因子：
6.1
通讯作者：
Parampreet Kaur;A. Zeh;N. Chaudhri;A. Gerdes;M. Okrusch
中科院分区：
文献类型：
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作者：
Parampreet Kaur;A. Zeh;N. Chaudhri;A. Gerdes;M. Okrusch
印度西北部阿拉瓦利造山带北方古元古代石英岩中的碎屑锆石沉积于1.85 ~ 1.82Ga之间，显示出一个独特的年龄峰，约为1.85Ga。1.85Ga和可变的，但大部分是亚太古宙的ε Hf 1.85 Ga，介于−1.3和−21.0之间，对应于铪模型年龄2.5到3.6Ga。这些数据表明，一个重要时期的改造古代（Eo-新太古代），强烈的非均质大陆地壳在这个时候。CA的流行。1.85Ga与俯冲作用有关的花岗岩类，约1.85Ga的碎屑锆石U-Pb年龄谱和ε Hft几乎一致。阿拉瓦利造山带和小喜马拉雅山脉内部的1.85Ga变质沉积岩表明，在晚古元古代，这两个造山带之间存在相似的沉积物源，因此存在地质联系。总之，这些数据限制了沉积，变质和俯冲相关的岩浆活动的快速继承，并支持一个活跃的地球动力学领域的解释，沿着整个北印度边缘约。1.85Ga.此外，将碎屑锆石数据与已发表的印度北部和哥伦比亚超大陆其他地壳块体的古地磁数据进行比较，表明印度北部与马达加斯加、华南华夏块体和韩国在哥伦比亚时代有密切的亲缘关系。
Detrital zircons from a Palaeoproterozoic quartzite, deposited between 1.85 and 1.82Ga in the northern Aravalli orogen of NW India, show a distinctive age peak of ca. 1.85Ga and variable, but largely subchondritic εHf1.85 Gabetween −1.3 and −21.0 corresponding to hafnium model ages of 2.5 to 3.6Ga. These data indicate an important period of reworking of ancient (Eo- to Neoarchaean), strongly heterogeneous continental crust at this time. Prevalence of ca. 1.85Ga subduction-related granitoids, almost identical U–Pb age spectra and εHftof detrital zircons in ca. 1.85Ga metasedimentary rocks in the Aravalli orogen and the inner Lesser Himalaya indicate similar sediment provenances and thus a geological connection between these two terranes during late Palaeoproterozoic. All together, the data constrain a rapid succession of sedimentation, metamorphism and subduction-related magmatic activity and support the interpretation of an active geodynamic realm along the entire north Indian margin at ca. 1.85Ga. Comparison of detrital zircon data in conjunction with published paleomagnetic data from north India and other crustal blocks of the Columbia supercontinent, additionally, suggest a close affinity of north India with Madagascar, the Cathaysia block of South China and South Korea during Columbia times.