魏小林,康波,甘承萍,保善斌,王维.东昆仑马尼特地区晚三叠世侵入岩地球化学特征及地质意义[J].西北地质,2019,52(1):41-51
东昆仑马尼特地区晚三叠世侵入岩地球化学特征及地质意义
Geochemical Characteristics and Geological Significance of Late Triassic Intrusive Rock in the Manite Area, East Kunlun
投稿时间:2018-04-09  修订日期:2018-09-04
DOI:10.19751/j.cnki.61-1149/p.2019.01.004
中文关键词:  石英闪长岩;晚三叠世;地球化学;马尼特地区;东昆仑
英文关键词:quartz diorite;Late Triassic;geochemistry;Manite area;East Kunlun
基金项目:中国地质调查局“东昆仑铜镍多金属资源基地调查”二级项目的子项目(121201011000150005-05)
作者单位
魏小林 青海省地质调查局, 青海 西宁 810001 
康波 青海省地质调查局, 青海 西宁 810001 
甘承萍 青海省第三地质矿产勘查院, 青海 西宁 810029 
保善斌 青海省地质调查局, 青海 西宁 810001 
王维 青海省地质调查局, 青海 西宁 810001 
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中文摘要:
      马尼特地区位于东昆仑阿尼玛卿成矿带,为确定该区石英闪长岩的形成时代、源区性质和构造背景,笔者对其进行了LA-ICP-MS锆石U-Pb年代学和同位素和地球化学研究。结果显示岩体侵位时间为(206.8±1.7)Ma(MSWK=0.50),属于晚三叠世。岩石SiO2含量为57.17%~68.55%,Na2O、K2O含量分别为3.31%~5.39%和1.52%~3.37%,全碱ALK=5.19%~7.24%,铝饱和指数A/CNK=0.93~1.25,属准铝质-弱过铝质系列岩石。稀土元素分布模式为轻稀土富集,具弱负Eu异常。岩石具有富集大离子亲石元素(Rb、Ba、K)和不相容元素(U、Th),不同程度亏损Nb、Ta、Ti、P等元素的特征。以上特征表明,岩石为钙碱性-高钾钙碱性的I型花岗岩,结合岩石成岩年龄、地球化学特征以及区域构造演化,岩石具有后碰撞岩浆活动的特征,推测其属于东昆仑地块与巴颜喀拉地块碰撞后地壳部分熔融的产物。
英文摘要:
      The Manite area is located in the Animaqing metallogenic belt of East Kunlun. In order to determine the formation time, magma source and tectonic setting of the quartz diorite in this area, the zircon LA-ICP-MS U-Pb dating, isotopic composition and geochemistry have been studied in this paper. The results show that the pluton emplacement time is (206.8±1.7)Ma(MSWK=0.50),belonging to the Late Triassic. The quartz diorite have SiO2 of 57.17%~68.55%,Na2O of 3.31%~5.39%, K2O of 1.52%~3.37%,ALK of 5.19%~7.24% and A/CNK of 0.93~1.25, they are Aluminiums and belong to calc-alkaline rock series. The REE distribution modes show the LREE accumulation and weak negative Eu anomalies. The quartz diorite is characterized by the enrichment of LILEs (Rb,Ba and K) and incompatible elements(U and Th), as well as the depletion of HFSEs (Nb,Ta,Ti and P). Above features show that this rock belongs to high-K calc-alkaline I-type granite. Combined with the geochronological data, geochemical characteristics and the regional tectonic evolution, it's included that this rock has the characteristics of post-collisional magmatism, and the quartz diorite was the product of crustal partial melting after the collision of the East Kunlun block and Bayan Har block.
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