Geochronology and geochemistry of late Carboniferous–middle Permian I- and A-type granites and gabbro–diorites in the eastern Jiamusi Massif, NE China: Implications for petrogenesis and tectonic setting
Geochronology and geochemistry of late Carboniferous–middle Permian I- and A-type granites and gabbro–diorites in the eastern Jiamusi Massif, NE China: Implications for petrogenesis and tectonic setting
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中国东北佳木斯地块东部晚石炭世—中二叠世 I 型和 A 型花岗岩和辉长闪长岩的年代学和地球化学：对岩石成因和构造环境的启示
DOI：
10.1016/j.lithos.2016.10.001
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发表时间：
2016-12
期刊：
影响因子：
3.5
通讯作者：
陈会军
中科院分区：
文献类型：
--
作者：
毕君辉;葛文春;杨浩;王智慧;许文良;杨进辉;邢德和;陈会军
中亚造山带东段佳木斯地块的晚石炭世-中二叠世岩浆活动为研究该地区的构造历史和地球动力学过程提供了重要证据。龙头桥岩体中的辉长闪长岩与两组同时代花岗岩组成了一套双峰式岩浆岩。精确的LA-ICP-MS锆石U-Pb年龄表明，花岗岩类和辉长闪长岩的侵位时代为晚石炭世-中二叠世（302-267 Ma）。和K2 O（3.65-5.89重量%）内容物，富含LILE（例如，第II类花岗岩为弱过铝质（A/CNK = 1.03-1.07），富碱（Na_2 O + K_2 O = 8.22- 8.90wt.%），具Nb、Ta、P、Ti负异常，与俯冲岩浆密切相关。低MgO（0.04-0.09 wt.%）和P2 O 5（0.01-0.04重量%）高Zr、Nb含量，高10，000 × Ga/Al比值，与铝质A型花岗岩地球化学特征相似。岩浆锆石εHf（t）值变化较大（+7.89 ~-5.60），两阶段Hf模式年龄（TDM 2）为0.8- 1.7Ga，表明前体岩浆起源于一个不均匀的源区，岩浆生成过程中有来自亏损地幔源区的年轻组分参与。铝质A型花岗岩岩浆可能是长英质地壳源高温部分熔融的产物，而其他花岗岩岩浆可能是镁铁质下地壳部分熔融的产物。龙头桥岩体的辉长闪长岩亏损Nb、Ta、P和Ti，除Ba、K和Pb有较大的正异常外，大部分LILE和HFSE呈平坦分布。这些特征反映了有限程度的地壳污染与俯冲有关的岩浆过程。结合前人的研究成果和佳木斯地块东部沿着各类岩石的性质，认为这些侵入岩形成于古太平洋洋壳向西俯冲过程中由挤压向伸展转变的地球动力学环境，可能是俯冲板块板片断裂的结果。
Late Carboniferous–middle Permian magmatism in the Jiamusi Massif of northeast China, in the eastern segment of the Central Asian Orogenic Belt (CAOB), provides critical evidence regarding the tectonic history and geodynamic processes in the region. The gabbro–diorites of the Longtouqiao pluton and two groups of coeval granite in the study area comprise a bimodal magmatic suite. Precise LA-ICP-MS U–Pb zircon ages indicate that the granitoids and gabbro–diorites were emplaced in the late Carboniferous–middle Permian (302–267 Ma).Group Igranites have high SiO2(70.75–77.04 wt.%) and K2O (3.65–5.89 wt.%) contents, are enriched in LILEs (e.g., Rb, Th, and U) relative to HFSEs and LREEs, and have negative Nb, Ta, P, and Ti anomalies, which collectively indicate affinities with subduction-related magmas.Group IIgranites are weakly peraluminous (A/CNK = 1.03–1.07) and are characterized by enrichment in alkalis (Na2O + K2O = 8.22–8.90 wt.%), low MgO (0.04–0.09 wt.%) and P2O5(0.01–0.04 wt.%) contents, high Zr and Nb contents, high 10,000 × Ga/Al ratios, and they are geochemically similar to aluminous A-type granites. All the magmatic zircons in these granitoids have great variations ofεHf(t) (+ 7.89 to − 5.60) and two-stage Hf model ages (TDM2) of 0.8–1.7 Ga, which suggest that the precursor magmas originated from a heterogeneous source that involved juvenile components derived from a depleted mantle source during magma generation. The aluminous A-type granite magmas were probably derived by high-temperature partial melting of a felsic crustal source, whereas the other granite magmas probably resulted from partial melting of a mafic lower crust. The gabbro–diorites of the Longtouqiao pluton are depleted in Nb, Ta, P, and Ti, and show flat distributions of most LILEs and HFSEs, except for large positive anomalies in Ba, K, and Pb. These features reflect a limited degree of crustal contamination associated with the subduction-related magmatic processes. These data, together with previously reported data and the nature of various rock types along the eastern part of the Jiamusi Massif, suggest that the intrusive rocks were formed in a geodynamic regime that changed from compression to extension during the westwards subduction of the Paleo-Pacific oceanic lithosphere, probably as a result of slab break-off of the subducting plate.
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影响因子：
1.8
作者：
Cheng Rui
通讯作者：
Cheng Rui
DOI：
--
发表时间：
2013
期刊：
--
影响因子：
--
作者：
Yu Jiejiang;Zhang Yan-long;Ge Wen-chun;Yang Hao
通讯作者：
Yu Jiejiang;Zhang Yan-long;Ge Wen-chun;Yang Hao
影响因子：
5.8
作者：
R. Larson
通讯作者：
R. Larson
影响因子：
1.5
作者：
Fu-Yuan Wu;Jin-Hui Yang;C. Lo;S. Wilde;Dejun Sun;B. Jahn
通讯作者：
Fu-Yuan Wu;Jin-Hui Yang;C. Lo;S. Wilde;Dejun Sun;B. Jahn
影响因子：
2.9
作者：
S. Wilde
通讯作者：
S. Wilde