Late Jurassic–Early Cretaceous irregular slab rollback of paleo-Pacific plate beneath southeastern China: Insights from the petrogenesis of volcanic rocks of Moshishan Group in Dazhou volcanic basin, Gan-Hang Belt
Late Jurassic–Early Cretaceous irregular slab rollback of paleo-Pacific plate beneath southeastern China: Insights from the petrogenesis of volcanic rocks of Moshishan Group in Dazhou volcanic basin, Gan-Hang Belt
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中国东南部古太平洋板块晚侏罗世—早白垩世不规则板片回滚——赣杭带达州火山盆地磨石山群火山岩成因的认识
DOI：
10.1016/j.lithos.2021.106137
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发表时间：
2021-03
期刊：
影响因子：
3.5
通讯作者：
Ruo-Xi Zhang
中科院分区：
文献类型：
--
作者：
Shui-Yuan Yang;Jia-Peng Liang;Shao-Yong Jiang;Xing Zhang;Ruo-Xi Zhang
晚中生代古太平洋板块向中国东南俯冲的地球动力学模式虽然已被普遍接受，但关于板块俯冲的确切模式仍存在争议。赣杭带达州火山盆地内磨石山群火山岩地层十分发育。在这项研究中，这些火山岩的地质年代学，元素地球化学和同位素组成进行了详细的调查，以限制其形成时代和岩石成因以及GHB的构造岩浆演化。LA-ICP-MS锆石U-Pb定年结果表明，达州火山盆地的火山喷发始于150.9 ± 2.7 ~ 128.8 ± 1.9 Ma，持续时间约为2000万年。这些火山岩具有较高的Ga/Al比值、较高的K2 O + Na 2 O和Zr + Nb + Ce + Y含量，以及较高的形成温度（~812-1022 °C），显示出与A型花岗岩的亲合性。这类A型火山岩形成于拉张构造环境，可能与古太平洋板块的板片回滚导致的弧后拉张作用相对应。磨石山群火山岩的εNd（t）值变化在−11.60 ~ −5.41之间，锆石εHf（t）值变化在−18.30 ~ −3.84之间，表明火山岩主要来源于准变质岩的部分熔融。不同比例的幔源物质也参与了它们的来源，如大双组早期很少或没有幔源物质的加入。但在高屋组、西山头组和九里坪组晚期，幔源物质的加入比例明显增加。研究发现，GHB西南部的火山岩形成于早白垩世（137-132 Ma），而东北部的火山岩形成于晚侏罗世~早白垩世（150-120 Ma）。沿着GHB分布有形成于与古太平洋板块俯冲有关的大陆弧环境的侏罗纪钙碱性花岗岩（181-151 Ma）。这表明，从弧环境为主的古太平洋板块俯冲到弧后拉张环境的特点是板卷回滚开始在~150 Ma的GHB。本文提出了一个不规则板片回滚模型来解释中国东南部GHB火山盆地的分布格局。GHB中的板卷回滚在整个区域内并不是同时开始的，也不是以均匀的速度开始的。GHB西南部的板卷回滚发生在137 ~ 132 Ma之间，而东北部的板卷回滚发生在150 ~ 120 Ma之间。此外，在~150 ~ 120 Ma之间，沿沿着GHB东北部产生A型花岗质岩浆的壳幔相互作用从早到晚逐渐加强。
The geodynamic model of the paleo-Pacific plate subduction beneath southeastern China during the Late Mesozoic, though generally accepted, remains controversial with respect to the exact plate subduction model. The Moshishan Group volcanic strata are well developed in the Dazhou volcanic basin in the Gan-Hang Belt (GHB). In this study, detailed investigations on geochronology, elemental geochemistry, and isotopic compositions of these volcanic rocks were performed to constrain their formation ages and petrogenesis as well as the tectonomagmatic evolution of the GHB. LA-ICP-MS zircon Usingle bondPb dating results show that the volcanic eruptions in the Dazhou volcanic basin began approximately 150.9 ± 2.7 Ma to 128.8 ± 1.9 Ma and lasted for ~20 Myr from the Late Jurassic to Early Cretaceous. These volcanic rocks show high Ga/Al ratio, high K2O + Na2O and Zr + Nb + Ce + Y contents, and high formation temperature (~812–1022 °C), indicating A-type granite affinity. Such types of A-type volcanic rocks formed in an extensional tectonic environment, likely corresponding to a back-arc extension due to the slab rollback of the paleo-Pacific plate. The εNd(t) values of the volcanic rocks of Moshishan Group vary from −11.60 to −5.41, and the zircon εHf(t) values vary from −18.30 to −3.84, indicating that these volcanic rocks were mainly derived from the partial melting of para-metamorphic rocks. Different proportions of mantle-derived materials were also involved in their sources, such as little or no addition of mantle-derived material in the early Dashuang Formation. However, a significantly increased proportion of mantle-derived material addition was found in the later Gaowu Formation, Xishantou Formation, and Jiuliping Formation. We found that the volcanic rocks in the southwestern GHB were formed during the Early Cretaceous (137–132 Ma), while those in the northeastern GHB formed during the Late Jurassic to Early Cretaceous (150–120 Ma). Jurassic calc-alkaline granites (181–151 Ma) that formed in a continental arc environment related to the paleo-Pacific plate subduction are also distributed along the GHB. This indicates that the shift from an arc environment dominated by the subduction of the paleo-Pacific plate to a back-arc extensional environment characterized by slab rollback began at ~150 Ma in the GHB. We propose an irregular slab rollback model beneath southeastern China to interpret the distribution pattern of the volcanic basins in the GHB. The slab rollback in the GHB did not initiate simultaneously, or with homogeneous velocity, throughout the region. Slab rollback in the southwestern part of the GHB occurred between 137 and 132 Ma, whereas in the northeastern part, rollback occurred between 150 and 120 Ma. In addition, the mantle-crust interaction that produced A-type granitic magmas along the northeastern part of the GHB gradually intensified from the early to late stage between ~150 and ~ 120 Ma.
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DOI：
--
发表时间：
2010
期刊：
Geological Journal of China Universities
影响因子：
--
作者：
Hu Li-hai
通讯作者：
Hu Li-hai
影响因子：
1.8
作者：
Y. Shui
通讯作者：
Y. Shui
影响因子：
3.8
作者：
Xiaolei Wang;Jincheng Zhou;J. Qiu;W. Zhang;Xiaoming Liu;G. Zhang
通讯作者：
Xiaolei Wang;Jincheng Zhou;J. Qiu;W. Zhang;Xiaoming Liu;G. Zhang
影响因子：
3.8
作者：
Jing‐Liang Guo;Shan Gao;Y. Wu;Ming Li;Kang Chen;Zhaochu Hu;Zhengwei Liang;Yongsheng Liu;
通讯作者：
Jing‐Liang Guo;Shan Gao;Y. Wu;Ming Li;Kang Chen;Zhaochu Hu;Zhengwei Liang;Yongsheng Liu;
影响因子：
3.5
作者：
Shuiyuan Yang;Shaoyong Jiang;K. Zhao;Yao-Hui Jiang;H. Ling;L. Luo
通讯作者：
Shuiyuan Yang;Shaoyong Jiang;K. Zhao;Yao-Hui Jiang;H. Ling;L. Luo