Zircon U–Pb age and Hf isotopic compositions of Mesozoic granitoids in southern Qiangtang, Tibet: Implications for the subduction of the Bangong–Nujiang Tethyan Ocean
Zircon U–Pb age and Hf isotopic compositions of Mesozoic granitoids in southern Qiangtang, Tibet: Implications for the subduction of the Bangong–Nujiang Tethyan Ocean
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西藏羌塘南部中生代花岗岩体锆石U-Pb年龄和Hf同位素组成：对班公怒江特提斯洋俯冲的启示
DOI：
10.1016/j.gr.2015.04.007
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发表时间：
2017
影响因子：
6.1
通讯作者：
Liyun Zhang
中科院分区：
文献类型：
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作者：
Qishuai Huang;Xiaoran Zhang;Yahui Yue;Liyun Zhang
中生代班公湖-怒江特提斯洋向北俯冲形成南羌塘岩浆带。为了更好地了解该带的岩石成因、沿着的时空分布，从西向东，在班公错、改则、东桥和安多地区选取了几个花岗岩类岩体的21个样品，进行了原位锆石U-Pb定年、Hf同位素和全岩化学分析。结果表明，本区岩浆活动时间较长（185-84 Ma），主要经历了侏罗纪（185-150 Ma）和早白垩世（126-100 Ma）两个阶段。除东部安多白垩纪二云母花岗岩属S型外，其余均为高钾钙碱性I型花岗岩。锆石Hf同位素组成表明，花岗岩类是由不同的源区物质形成的。班公错和东桥花岗岩类的锆石εHf（t）值较高，为− 1.3-13.6，较年轻的TDMCage年龄为293-1263 Ma，表明源区相对较年轻;改则和安多花岗岩类的εHf（t）值较低，为− 16.1-2.9，较老的TDMCage年龄为999-2024 Ma，表明源区较老。Sr/Y比值和TZr值表明，这些烃源岩在不同的P-T条件下熔融。两个阶段花岗岩类的Sr/Y比值均随年龄的减小而增大。而侏罗纪花岗岩类的TZr则随年龄的减小而减小，而白垩纪花岗岩类的TZr则随年龄的减小而增大。这些花岗岩类的对比鲜明的地球化学特征可能是由不同的贡献板派生的流体参与侏罗纪和白垩纪花岗岩岩浆的生成，即增加量的流体在侏罗纪，而减少量的流体在白垩纪。因此，认为侏罗纪和白垩纪岩浆活动可能分别与班公湖-怒江特提斯洋的俯冲和闭合有关。侏罗纪和白垩纪花岗岩类的年龄模式表明班公湖-怒江特提斯洋斜向俯冲，拉萨地块和羌塘地块发生穿时碰撞。
The southern Qiangtang magmatic belt was formed by the north-dipping subduction of the Bangong–Nujiang Tethyan Ocean during Mesozoic. To better understand the petrogenesis, time–space distribution along the length of this belt, 21 samples of several granitoid bodies, from west to east, in the Bangong Co, Gaize, Dongqiao and Amdo areas were selected for in-situ zircon U–Pb dating, Hf isotopic and whole-rock chemical analyses. The results suggest a prolonged period of magmatic activity (185–84 Ma) with two major stages during the Jurassic (185–150 Ma) and the Early Cretaceous (126–100 Ma). Both the Jurassic and Cretaceous granitoids are high-K calc-alkaline I-type rocks, except the Cretaceous two-mica granite from Amdo in the east, which belongs to S-type. The granitoids are generated from different source materials as indicated by zircon Hf isotopic compositions. The Bangong Co and Dongqiao granitoids show high zircon εHf(t) values of − 1.3–13.6 with younger TDMCages of 293–1263 Ma, suggesting a relatively juvenile source; whereas the Gaize and Amdo granitoids have low εHf(t) values of − 16.1–2.9 with older TDMCages of 999–2024 Ma, indicating an old crustal contribution. These source rocks melt at different P–T conditions as suggested by Sr/Y ratio and TZr. The Sr/Y ratio of both stage granitoids increases with decreasing age. However, the TZrof the Jurassic granitoids decreases, whereas the TZrof the Cretaceous granitoids increases with decreasing age. The contrasting geochemical signatures of these granitoids may be controlled by the varying contribution of slab-derived fluids involved in the generation of the Jurassic and Cretaceous granitic magmas; i.e. increasing amount of fluids in the Jurassic, whereas decreasing amount of fluids in the Cretaceous. Therefore, it is proposed that the Jurassic and Cretaceous magmatism may be related to subduction and closure of the Bangong–Nujiang Tethyan Ocean, respectively. The age pattern of the Jurassic and Cretaceous granitoids suggests an oblique subduction of the Bangong–Nujiang Tethyan Ocean and a diachronous collision between the Lhasa and Qiangtang blocks.
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影响因子：
--
作者：
Michael Haschke;W. Siebel;A. Günther;E. Scheuber
通讯作者：
Michael Haschke;W. Siebel;A. Günther;E. Scheuber
藏中安多地体的构造演化：岩石化学与锆石U-Pb年代学
影响因子：
1.8
作者：
Zhang, Ze-Ming;Dong, Xin;Liu, Feng;Lin, Yan-Hao;Yan, Rong;Santosh, M.
通讯作者：
Santosh, M.
DOI：
10.1098/rsta.1988.0124
发表时间：
1988-12
期刊：
Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences
影响因子：
--
作者：
N. Harris;Xu Ronghua;C. Lewis;Jin Chengwei
通讯作者：
N. Harris;Xu Ronghua;C. Lewis;Jin Chengwei
影响因子：
3.5
作者：
Jinxiang Li;K. Qin;Guangming Li;J. Richards;Junxing Zhao;Mingjian Cao
通讯作者：
Jinxiang Li;K. Qin;Guangming Li;J. Richards;Junxing Zhao;Mingjian Cao
影响因子：
3
作者：
Weiliang Wang;J. Aitchison;C. Lo;Q. Zeng
通讯作者：
Weiliang Wang;J. Aitchison;C. Lo;Q. Zeng