Zircon U/Pb dating and Hf-O isotopes of the Zhouan ultramafic intrusion in the northern margin of the Yangtze Block, SW China: Constraints on the nature of mantle source and timing of the supercontinent Rodinia breakup
Zircon U/Pb dating and Hf-O isotopes of the Zhouan ultramafic intrusion in the northern margin of the Yangtze Block, SW China: Constraints on the nature of mantle source and timing of the supercontinent Rodinia breakup
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扬子地块北缘周安超镁铁质岩体的锆石U/Pb定年及Hf-O同位素：对地幔源性质及超大陆Rodinia裂解时间的制约
DOI：
10.1007/s11434-012-5435-1
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发表时间：
2013-03
影响因子：
--
通讯作者：
Zhao JunHong
中科院分区：
文献类型：
--
作者：
Wang MengXi;Wang ChristinaYan;Zhao JunHong
扬子地块北缘周安超镁铁质岩体主要由辉橄榄岩组成。锆石颗粒形状不规则，具有明显的振荡和扇形分带，Th/U比值在0.8 ~ 10.6之间，为岩浆成因。206pb /238U的加权平均年龄为637±4 Ma (2σ,n=15)，可认为是周安岩体的结晶年龄。锆石颗粒的δ 18o值为5.2‰~ 7.0‰，平均值为5.8±0.4‰（1σ,n=33），与锆石的地幔δ 18o值相近。它们的176hf /177Hf(t)比值在0.282410 ~ 0.282594之间，δ Hf(t)值在1.3 ~ 7.6之间，低于亏缺地幔对应值（~ 15），表明地幔源富集。富集的地幔源可能是由俯冲板块的交代岩石圈地幔形成的。在水枣盆地，大量~ 635 Ma的基性-超镁铁质侵入岩与姚岭河组同时期的双峰火山活动有关，显示出大陆裂谷环境。该地区的~ 635 Ma岩浆事件可能是新元古代扬子地块北缘Rodinia超大陆最后一次分裂的产物。
The Zhouan ultramafic intrusion in the northern margin of the Yangtze Block is mainly composed of lherzolite. Zircon grains selected from lherzolite are irregular in shape with distinct oscillatory and sector zoning and have Th/U ratios ranging from 0.8 to 10.6, indicating a magmatic origin. The weighted average206Pb/238U age is 637±4 Ma (2σ,n=15), which can be considered as the crystallization age of the Zhouan intrusion. Zircon grains haveδ18O values ranging from 5.2‰ to 7.0‰, with an averaged value of 5.8±0.4‰ (1σ,n=33), similar to the mantleδ18O value of zircon. Their176Hf/177Hf(t)ratios range from 0.282410 to 0.282594 withɛHf(t) values ranging from 1.3 to 7.6, lower than the corresponding value of the depleted mantle (∼15), indicating an enriched mantle source. The enriched mantle source may have generated from a metasomatized lithospheric mantle with subducted slab. A number of ∼635 Ma mafic-ultramafic intrusions in the Suizao basin are associated with coeval bimodal volcanics of the Yaolinghe Formation, indicating a continental rift setting. The ∼635 Ma magmatic event in this region may represent the product of the last breakup of the Rodinia supercontinent in the northern margin of the Yangtze Block at Neoproterozoic.
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DOI：
--
发表时间：
2007
期刊：
Acta Geological Sinica
影响因子：
--
作者：
Cai Zhiyong
通讯作者：
Cai Zhiyong
影响因子：
--
作者：
Jian Wang;Xian‐Hua Li;T. Duan;Dunyi Liu;B. Song;Zhongxiong Li;Yonghua Gao
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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：
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通讯作者：
Mei‐Fu Zhou;A. Kennedy;M. Sun;J. Malpas;C. Lesher
影响因子：
5.8
作者：
R. Larson
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影响因子：
3.8
作者：
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Xiaolei Wang;Jincheng Zhou;J. Qiu;W. Zhang;Xiaoming Liu;G. Zhang