| 南秦岭勉略带两河弧内裂陷内火山岩组合地球化学 |
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| 引用本文： | 赖绍聪,杨瑞瑛.南秦岭勉略带两河弧内裂陷内火山岩组合地球化学[J].岩石学报,2000,16(3):317-326. |
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| 作者姓名： | 赖绍聪 杨瑞瑛 |
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| 作者单位： | 1. 西北大学地质系,西安,710069
2. 中国科学院高能物理研究所,北京,100080 |
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| 基金项目： | 国家自然科学基金秦岭重点项目 (4973 2 0 80 )，中科院 LNAT核分析技术联合开放实验室 (97B0 0 6)，陕西省教委专项科研基金资助 |
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| 摘 要： | 两河火山岩岩片位于秦岭微板块与扬子板块的分界断裂－巴山弧形构造混杂带内。岩石内亚碱性拉班系列玄武质岩石和钙碱性英安岩、流纹岩组成。基性岩和酸性岩均具有高Ｂａ，低Ｔｈ、Ｕ，显著的Ｎｂ、Ｔａ亏损和Ｔｉ的负异常等地球化学特征，玄武岩的Ｔｈ／Ｙｂ－Ｔａ和Ｔｉ／Ｚｒ－Ｔｉ／Ｙ不活动痕量元素组合特征指示这套火山岩可能产于弧间盆地环境。是勉略洋盆在古生代晚期－中生代早期发育期间洋壳俯冲及弧内裂陷的岩浆作用产物。
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| 关 键 词： | 火山岩 地球化学 岩石大地构造 勉略缝合带 秦岭 |
Geochemistry
of the volcanic rock association from Lianghe area in Mianlue suture zone, southern
Qinling and its tectonic significance |
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| Lai Shaocong,Zhang Guowei and Yang Ruiying..Geochemistry
of the volcanic rock association from Lianghe area in Mianlue suture zone, southern
Qinling and its tectonic significance[J].Acta Petrologica Sinica,2000,16(3):317-326. |
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| Authors: | Lai Shaocong Zhang Guowei and Yang Ruiying |
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| Institution: | Lai Shaocong,Zhang Guowei and Yang Ruiying.. Department of Geology,Northwest University,Xian,Chin,. Institute of High Energy Physics,Chinese Academy of Sciences,Beijing,China. |
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| Abstract: | The volcanic rock slab in Lianghe area
is located in the boundary tectonic zone Bashan arcuate tectonic melange between Qinling
microplate and Yangtze plate. The rocks consisted of subalkaline tholeiitic basalt and
calc-alkaline dacitic rhyolite. Both of the basalt and dacitic rhyolite exhibit the
typical geochemical features of high content of element Ba, low content of elements Th and
U, remarkable depletion of element Nb, Ta and Ti. Especially, the Th/Yb-Ta/Yb and
Ti/Zr-Ti/Y features of the basalt indicate that the volcanic rock association in the
studied area developed in a special tectonic setting which belongs to a rift valley within
an island-arc. The volcanic rock association in the studied area was the result of
magmatism that due to the ancient oceanic crust subduction and rift valley development
within the island-arc during the evolutionary process of Mianlue ancient ocean basin at
Middle Paleozoic-Early Mesozoic era. This volcanic rock block should be an important
evidence which indicates that the Mianxian-Lueyang suture zone had extended to the Bashan
arcuate area. |
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| Keywords: | Volcanic rock Geochemistry Petrotectonics Mianlue suture zone |
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