| 浙东地区东园花岗岩体年代学、地球化学特征及其地质意义 |
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| 引用本文： | 廖圣兵,陈荣,褚平利,曾剑威,张彦杰,王存智,黄文成.浙东地区东园花岗岩体年代学、地球化学特征及其地质意义[J].大地构造与成矿学,2017,41(5). |
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| 作者姓名： | 廖圣兵 陈荣 褚平利 曾剑威 张彦杰 王存智 黄文成 |
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| 作者单位： | 中国地质调查局南京地质调查中心,江苏南京,210016 |
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| 基金项目： | 中国地质调查局“浙江1∶50000崇仁镇、长乐镇、岭口镇、巍山镇幅区域地质调查”项目 |
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| 摘 要： | 浙东地区岩浆岩广泛分布,受区域构造控制较明显,总体沿北东向余姚-丽水断裂带分布。本文对东园花岗岩体开展了详细的年代学和岩石地球化学研究。东园岩体主要由二长花岗岩、石英二长岩和少量花岗岩组成,主岩体二长花岗岩的LA-ICP-MS锆石U-Pb年龄为235.6±0.7 Ma(MSWD=0.97,2σ),花岗岩为238.1±0.8 Ma(MSWD=1.3,2σ),均属中三叠世产物。二长花岗岩和石英二长岩为准铝质-弱过铝质的钙碱性花岗岩,具高硅(62.94%~75.29%)、富碱(Na_2O+K_2O=8.17%~9.34%)且富钾(K_2O=4.54%~5.63%)的特征,轻重稀土分馏明显,具有较强的Eu正异常(δEu=0.94~2.43),明显亏损高场强元素(HFSE)Nb、P、Ti,而相对富集Th、Hf,富集轻稀土元素(LREE)和大离子亲石元素(LILE)Rb,相对贫Ba。岩体属高(-中等)分异I型花岗岩,岩浆来源于具弧属性的加厚地壳部分熔融,形成于同碰撞向后碰撞阶段转变的大地构造环境,可能与太平洋板块向华南板块俯冲作用事件有关。
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| 关 键 词： | 浙东地区 印支期 锆石U-Pb年代学 I型花岗岩 后造山 |
Geochronological and Geochemical Characteristics of the Dongyuan Granite Pluton in Eastern Zhejiang Province,and their Geological Significance |
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| LIAO Shengbing,CHEN Rong,CHU Pingli,ZENG Jianwei,ZHANG Yanjie,WANG Cunzhi,HUANG Wencheng.Geochronological and Geochemical Characteristics of the Dongyuan Granite Pluton in Eastern Zhejiang Province,and their Geological Significance[J].Geotectonica et Metallogenia,2017,41(5). |
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| Authors: | LIAO Shengbing CHEN Rong CHU Pingli ZENG Jianwei ZHANG Yanjie WANG Cunzhi HUANG Wencheng |
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| Abstract: | Igneous rocks are widespread in the eastern Zhejiang province,which commonly occur along the Yuyao-Lishui North-East trending fault zones.In this paper,detailed zircon U-Pb geochronological and element geochemical studies were carried out for the Dongyuan granitoids.The granitoids mainly consist of monzogranite,quartz monzonite,and granite.LA-ICP-MS zircon U-Pb dating of the monzogranite and granite yielded weighted average ages of 235.6±0.7 Ma and 238.1±0.8 Ma,respectively.The monzogranite and granite are peraluminouscal-alkaline,characterized by high SiO2 (62.94％-75.29％),high potassium and alkali content (K2O=4.54％-5.63％,Na2O+K2O=8.17％-9.34％).The granitic rocks are enriched in LILE and LREE,and depleted in HFSE.LREE fractionation are more obviously than HREE,showing significant positive Eu anomalies (δEu=0.94-2.43),and depletion of Sr,Ba,P,Ti,Nb,enrichment of Rb,Th,Hf.The geochemical characteristics show that the Dongyuan granites are moderate to high fractionated I-type granite.lndosinian magmatic activities in the eastern Zhejiang province mainly took place in the Early Mesozoic,formed in a transitional tectonic setting from syn-collision to post-collision.The magmas were the product of partial melting of the thickened arc-like crust related to the subduction of the Pacific plate underneath the South China Plate. |
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| Keywords: | eastern Zhejiang province Indosinian zircon U-Pb dating I-type granites post-orogenic |
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