Precambrian tectonothermal evolution of South Qinling and its affinity to the Yangtze Block: Evidence from zircon ages and Hf-Nd isotopic compositions of basement rocks
Precambrian tectonothermal evolution of South Qinling and its affinity to the Yangtze Block: Evidence from zircon ages and Hf-Nd isotopic compositions of basement rocks
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南秦岭前寒武纪构造热演化及其与扬子地块的关系：来自基岩锆石年龄和Hf-Nd同位素组成的证据
DOI：
10.1016/j.precamres.2016.10.005
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发表时间：
2016-11
影响因子：
3.8
通讯作者：
Chen Fukun
中科院分区：
文献类型：
--
作者：
Nie Hu;Yao Jin;Wan Xin;Zhu Xi Yan;Siebel Wolfgang;Chen Fukun
南秦岭是中国中部中生代秦岭造山带的一个构造块体，一般认为在前寒武纪与扬子地块有密切的亲缘关系。近年来，人们认识到南秦岭地块存在多个前寒武纪基底杂岩。本文报道了南秦岭最古老的岩石单元——杜岭杂岩的锆石U-Pb年龄和Hf同位素数据，以及整个岩石的Sr-Nd同位素数据，揭示了该基底的早期演化。双岭杂岩主要由副长岩和花岗质正长岩组成。3个正长岩样品的岩浆锆石U-Pb年龄均为2.5 Ga，表明其存在早古元古代岩浆活动。锆石Hf同位素组成暗示3.0 Ga以来的幼年地壳发育。2.5 Ga的岩浆活动表明南秦岭前寒武纪与太古宙孔岭地系（扬子地块最古老的基底）存在差异。3个副辉岩样品含有不同年龄、不同来源的复杂碎屑锆石。它们的U-Pb年龄主要集中在2.5 Ga、2.0 Ga、1.5 Ga和800 Ma左右。年龄为2.0 Ga和800 Ma的锆石颗粒Th/U比值较低，无振荡带，暗示有2期变质叠印。这类古元古代变质事件在扬子地块也有迹可寻，证实了其与南秦岭的密切关系。碎屑锆石中新元古代角闪岩相变质作用的记录表明，扬子地块由辐合环境向伸展环境的构造转变一定发生在800 Ma之前。
South Qinling is a tectonic block in the Mesozoic Qinling orogenic belt, central China, which is generally believed to have had tight affinity with the Yangtze Block during Precambrian times. In recent years, it has been recognized that the South Qinling Block hosts several Precambrian basement complexes. Here we report U-Pb ages and Hf isotopic data for zircons and Sr-Nd isotopic data for whole-rocks of the Douling complex, the oldest rock unit exposed in South Qinling, to reveal the early evolution of this basement. The Douling complex mainly consists of paragneisses and granitic orthogneisses. Zircons of magmatic origin from three orthogneiss samples give U-Pb ages ofc.2.5 Ga, suggesting an early Paleoproterozoic magmatic activity. Zircon Hf isotopic compositions imply the growth of juvenile crust sincec.3.0 Ga. The magmatic activity atc.2.5 Ga points to differences in the Precambrian history between South Qinling and the Archean Kongling terrene, the oldest basement of the Yangtze Block. Three paragneiss samples contain complex detrital zircons of different ages and origins. Their U-Pb ages mainly cluster around 2.5 Ga, 2.0 Ga, 1.5 Ga and 800 Ma. Zircon grains with ages of 2.0 Ga and 800 Ma have low Th/U ratios and no oscillatory zoning, implying two episodes of metamorphic overprint. Such Paleoproterozoic metamorphic event has also been traced in the Yangtze Block, confirming its close relationship with South Qinling. The record of Neoproterozoic amphibolite-facies metamorphism in detrital zircons suggest that the tectonic transition from convergent to extensional environments in the Yangtze Block must have occurred later than 800 Ma ago.
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影响因子：
5.3
作者：
Wang, Wei;Cawood, Peter A.;Zhou, Mei-Fu;Zhao, Jun-Hong
通讯作者：
Zhao, Jun-Hong
DOI：
10.1086/341762
发表时间：
2002-09
期刊：
The Journal of Geology
影响因子：
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作者：
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Mei‐Fu Zhou;A. Kennedy;M. Sun;J. Malpas;C. Lesher
影响因子：
3.8
作者：
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Kang Chen;Shan Gao;Y. Wu;Jing‐Liang Guo;Zhaochu Hu;Yongsheng Liu;K. Zong;Zhengwei Liang;
影响因子：
3.8
作者：
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通讯作者：
Shao‐Bing Zhang;Yong Zheng;Y. Wu;Zi‐Fu Zhao;Shan Gao;Fu-Yuan Wu
影响因子：
6.1
作者：
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通讯作者：
F. Hu;Shuwen Liu;M. Santosh;Z. Deng;Wei Wang;Wanyi Zhang;Ming Yan