Proterozoic rapakivi granites from the North Qaidam orogen, NW China: Implications for basement attribution
Proterozoic rapakivi granites from the North Qaidam orogen, NW China: Implications for basement attribution
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中国西北柴达木造山带元古代拉帕基维花岗岩：对基底归属的影响
DOI：
10.1016/j.gr.2014.09.018
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发表时间：
2015-12
影响因子：
6.1
通讯作者：
Hu Nenggao
中科院分区：
文献类型：
--
作者：
Wang Xiaoxia;Wang Tao;Castro Antonio;Hu Nenggao
大量的元古代（~ 1700 Ma）环斑花岗岩出现在几个盆地中，特别是在北方。在中国中央造山系西段柴北缘古生代造山带中发现了类似的元古代环斑花岗岩。SHRIMP锆石U-Pb定年结果为1778 ± 17和1778 ± 12 Ma。这些花岗岩具有典型的环斑结构。它们为亚铁、碱性-碱性钙、偏铝质-过铝质，具有高Ga/Al比、高Na_2 O + K_2 O和稀土元素（Eu除外）含量，低MgO、CaO和Sr含量的特点。这是典型的A型花岗岩特征。花岗岩全岩εNd（t）值介于− 6.09 ~ − 5.74之间，Nd模式年龄为2762 ~ 2733 Ma;锆石εHf（t）值介于− 8.3 ~ − 5.2之间，两阶段Hf模式年龄为2944 ~ 2800 Ma，表明其来源于古老的陆壳。年龄、环斑结构和地球化学特征表明，这些花岗岩与华北地区典型的元古代（~ 1700 Ma）环斑花岗岩非常接近，属于北方元古代环斑花岗岩群。这表明，位于CCOS西部的柴北缘造山带部分基底与华北克拉通基底相似，或可能起源于华北克拉通基底，并参与了CCOS。这为解决该造山带基底成因的争论提供了新的资料。
Voluminous Proterozoic (~ 1700 Ma) rapakivi granites occur in several cratons, especially in the northern hemisphere. Similar Proterozoic rapakivi granites have recently been recognized in the Paleozoic North Qaidam orogen, western segment of the China Central Orogenic System (CCOS). SHRIMP zircon U–Pb dating of these granites yielded ages of 1778 ± 17 and 1778 ± 12 Ma. These granites exhibit typical rapakivi textures. They are ferroan, alkalic to alkalic-calc, metaluminous to peraluminous and characterized by high Ga/Al ratios, Na2O + K2O and rare earth elements (apart from Eu) contents, but low MgO, CaO and Sr contents. These are typical A-type granite features. Whole-rock εNd(t) values of the granites range from − 6.09 to − 5.74 with Nd model ages of 2762 to 2733 Ma, and their zircon εHf(t) values are from − 8.3 to − 5.2 with two-stage Hf model ages of 2944 to 2800 Ma, suggesting that these rocks were derived from old continental crust. The ages, rapakivi texture and geochemical features suggest that these granites are very close to typical Proterozoic (~ 1700 Ma) rapakivi granites within the North China Craton (NCC) and belong to the group of Proterozoic rapakivi granites of the northern hemisphere. These indicate that part of the basement of the North Qaidam orogen in the western CCOS is similar to that of the NCC or was probably derived from it, and then became involved in the CCOS. This provides new data to solve the dispute on the basement origin in this orogen.
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影响因子：
3.9
作者：
Shuguang Song;Lifei Zhang;Y. Niu;L. Su;B. Song;Dunyi Liu
通讯作者：
Shuguang Song;Lifei Zhang;Y. Niu;L. Su;B. Song;Dunyi Liu
影响因子：
--
作者：
M. Key
通讯作者：
M. Key
影响因子：
3.5
作者：
P. Patchett;M. Tatsumoto
通讯作者：
P. Patchett;M. Tatsumoto
影响因子：
3.4
作者：
J. Zhang;F. Meng;Y. Wan
通讯作者：
J. Zhang;F. Meng;Y. Wan
影响因子：
3.4
作者：
S. Song;L. F. Zhang;Y. Niu;C. Wei;J. Liou;G. Shu
通讯作者：
S. Song;L. F. Zhang;Y. Niu;C. Wei;J. Liou;G. Shu