The Shimian ophiolite in the western Yangtze Block, SW China: Zircon SHRIMP U-Pb ages, geochemical and Hf-O isotopic characteristics, and tectonic implications
The Shimian ophiolite in the western Yangtze Block, SW China: Zircon SHRIMP U-Pb ages, geochemical and Hf-O isotopic characteristics, and tectonic implications
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扬子地块西部石棉蛇绿岩：锆石SHRIMP U-Pb年龄、地球化学和Hf-O同位素特征及构造意义
DOI：
10.1016/j.precamres.2017.06.005
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发表时间：
2017-09
影响因子：
3.8
通讯作者：
Guangming Ren
中科院分区：
文献类型：
--
作者：
Peiyuan Hu;Qingguo Zhai;Jun Wang;Yue Tang;Guangming Ren
扬子陆块西部石棉镁铁质-超镁铁质岩是一个受新元古代花岗岩侵入并与新元古代苏雄群相对断裂的构造破碎杂岩。根据野外产状、时代和地球化学特征的差异，将石棉镁铁质-超镁铁质岩分为中元古代晚期石棉蛇绿岩和新元古代早期辉长岩两套。晚中元古代石棉蛇绿岩主要由蛇纹岩、辉长岩、玄武岩和杆柱岩组成。采用高灵敏度高分辨离子探针（SHRIMP）对辉长岩样品进行锆石U-Pb定年，获得1066 ± 11 Ma的年龄，代表石棉蛇绿岩的形成年龄。所有玄武岩和辉长岩样品的拉斑玄武岩和具有正常的洋中脊玄武岩（N-MORB）一样的不动元素模式与负Nb和Ti异常。低的锆石δ 18 O（4.6-5.6 ‰）和高的锆石εHf（t）正值（+10.8-+18.3）表明它们来自亏损地幔源区。这些特征与SSZ型蛇绿岩中的玄武质岩石具有可比性。新元古代早期辉长岩侵入石棉蛇绿岩中。公元937年。这些辉长岩的地球化学和同位素特征与岛弧玄武岩相似。综合前人的研究和本文的资料，我们认为扬子地块西北部可能经历了中元古代晚期-新元古代早期的穿时俯冲作用。
The Shimian mafic-ultramafic rocks in the western Yangtze Block is a structurally dismembered complex which is intruded by the Neoproterozoic granite and faulted against the Neoproterozoic Suxiong Group. In this study, we divide the Shimian mafic-ultramafic rocks into two suites including the Late Mesoproterozoic Shimian ophiolite and Early Neoproterozoic gabbros, based on differences in the field occurrence, age, and geochemical characteristics. The Late Mesoproterozoic Shimian ophiolite mainly consist of serpentinites, gabbros, basalts, and rodingites. Zircon U–Pb dating using a sensitive high-resolution ion microprobe (SHRIMP) on a gabbro sample yielded an age of 1066 ± 11 Ma, representing the formation age of the Shimian ophiolite. All basalt and gabbro samples are tholeiitic and have normal mid-ocean ridge basalt (N-MORB)-like immobile element patterns with negative Nb and Ti anomalies. The low zircon δ18O (4.6–5.6 ‰) and high positive zircon εHf(t) (+10.8 to +18.3) values indicate that these rocks were derived from a depleted mantle source. These features are comparable with those of the basaltic rocks in SSZ-type ophiolite. The Early Neoproterozoic gabbros intruded into the Shimian ophiolite at ca. 937 Ma. The geochemical and isotopic characteristics of these gabbros are similar to those of the island arc basalts. Integrating previous studies with the data presented in this contribution, we suggest that the northwestern Yangtze Block has probably witnessed the Late Mesoproterozoic–Early Neoproterozoic diachronous subduction.
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DOI：
10.1086/341762
发表时间：
2002-09
期刊：
The Journal of Geology
影响因子：
--
作者：
Mei‐Fu Zhou;A. Kennedy;M. Sun;J. Malpas;C. Lesher
通讯作者：
Mei‐Fu Zhou;A. Kennedy;M. Sun;J. Malpas;C. Lesher
影响因子：
1.8
作者：
Shen Wei
通讯作者：
Shen Wei
春季孟加拉湾涡旋生成及其在亚洲夏季风爆发中的作用
DOI：
10.1007/s11430-010-4125-6
发表时间：
2011
期刊：
Science China Earth Sciences
影响因子：
--
作者：
Wu GuoXiong;Guan Yue;Wang TongMei;Liu YiMin;Yan JingHui;Mao JiangYu
通讯作者：
Mao JiangYu
DOI：
--
发表时间：
2013
期刊：
--
影响因子：
--
作者：
Y. Wang;T. Gu;X. Wang;Y. Gao;K. Jochum;W. Müller
通讯作者：
Y. Wang;T. Gu;X. Wang;Y. Gao;K. Jochum;W. Müller
影响因子：
5.3
作者：
S. Hart;H. Staudigel
通讯作者：
S. Hart;H. Staudigel