新疆北部二叠纪基性岩墙群岩浆作用及其动力学背景

新疆北部西准噶尔、吐哈盆地、东天山、西天山以及塔里木东北缘广泛发育的二叠纪(260-290Ma)基性岩墙群与塔里木大火成岩省形成时代相近。基性岩墙群主量元素与MgO含量具有较好的相关性,富集Rb、Ba和Sr等大离子亲石元素以及轻稀土元素,亏损Nb、Ta和Ti等高场强元素,无明显Eu异常,与岛弧岩浆特征相似。εNd(t)值为-11.25-7.86,初始N(87Sr)/N(86Sr)值为0.703-0.710。西天山基性岩墙群亏损轻稀土元素,塔里木东北缘亏损Sr。新疆北部二叠纪基性岩墙群岩浆可能起源于富集型软流圈地幔源区,岩浆演化过程中存在不同程度的地壳物质或俯冲交代岩石圈地幔的混染,其中西准噶尔...

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Published in地球科学与环境学报 Vol. 36; no. 3; pp. 73 - 82
Main Author 林瑶 汤庆艳 张铭杰 焦建刚 陈思童 虎啸
Format Journal Article
LanguageChinese
Published 兰州大学 地质科学与矿产资源学院,甘肃 兰州,730000%长安大学 地球科学与资源学院,陕西 西安,710054 2014
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Summary:新疆北部西准噶尔、吐哈盆地、东天山、西天山以及塔里木东北缘广泛发育的二叠纪(260-290Ma)基性岩墙群与塔里木大火成岩省形成时代相近。基性岩墙群主量元素与MgO含量具有较好的相关性,富集Rb、Ba和Sr等大离子亲石元素以及轻稀土元素,亏损Nb、Ta和Ti等高场强元素,无明显Eu异常,与岛弧岩浆特征相似。εNd(t)值为-11.25-7.86,初始N(87Sr)/N(86Sr)值为0.703-0.710。西天山基性岩墙群亏损轻稀土元素,塔里木东北缘亏损Sr。新疆北部二叠纪基性岩墙群岩浆可能起源于富集型软流圈地幔源区,岩浆演化过程中存在不同程度的地壳物质或俯冲交代岩石圈地幔的混染,其中西准噶尔、东天山、西天山和吐哈盆地岩墙经历了板片俯冲流体交代的岩石圈地幔混染,东天山及塔里木东北缘基性岩墙在岩浆演化过程中受到明显的地壳物质混染。新疆北部二叠纪基性岩墙群可能是地幔柱岩浆作用不同演化过程的产物。
Bibliography:61-1423/P
LIN Yao , TANG Qing-yan , ZHANG Ming-jie , JIAO Jian-gang , CHEN Si-tong , HU Xiao (1. School of Earth Sciences, Laazhou University, Lanzhou 730000, Gansu, China; 2. School of Earth Science and Resources, Chang'an University, Xi'an 710054, Shaanxi, China)
mantle plume; contamination; magma evolution; mafic dyke; Permian; Xinjiang
Permian(260-290Ma)mafic dyke swarms in the northern of Xinjiang widely develop in West Junggar,Turpan-Hami Basin,East Tianshan,West Tianshan and the northeast margin of Tarim.The formation age of mafic dyke swarm is similar to that of Tarim large igneous provinces.The correlations between contents of major elements and MgO of mafic dyke swarms are obvious.Mafic dykes are enriched in large ion lithophile elements(Rb,Ba,Sr,etc.)and light rare earth elements(LREE),and depleted in high field strength element(Nb,Ta,Ti,etc.),and there is no obvious Eu anomaly,the characteristics are similar to island arc magma.εNd(t)values of mafic dykes are-11.25-7.86,and the initial N(87Sr)/N(86Sr
ISSN:1672-6561