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
发布时间：2018-11-13 15:45
【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。
[Abstract]:Magmatic rocks are widely distributed in eastern Zhejiang, which is controlled by regional structure and distributes along the Yuyao-Lishui fault zone. Detailed geochronological and petrogeochemical studies of the Dongyuan granite body have been carried out in this paper. The Dongyuan rock body is mainly composed of monzogranite, quartz monosite and a small amount of granite. The LA-ICP-MS zircon U-Pb age of the main monzomorphic granite is 235.6 卤0.7 Ma (MSWD=0.97,2 蟽) and the granite is 238.1 卤0.8 Ma (MSWD=1.3,2 蟽). They all belong to the products of the Middle Triassic. The calc-alkaline granites of bauxite and quartz monzonite are characterized by high silicon (62.94%), and weak peraluminous calc-alkaline granites (75.29%). The characteristics of Na_2O K _ 2O _ (8.17) and K _ 2O _ (4.54) are 9.34% and 5.63% respectively. The fractionation of light and heavy rare earths is obvious, with strong Eu positive anomaly (未 Eu=0.94~2.43) and obvious depletion of high field strength element (HFSE) Nb,. Th,Hf, enriched light rare earth element (LREE) and large ion lithophile element (LILE) Rb, (LILE) Rb,) was relatively poor in Ba.. The magma originated from the partial melting of the thickened crust with arc property, and formed in the tectonic environment of the same collision to the post-collision stage, and the magma originated from the partial melting of the thickened crust with arc properties, and the rock mass is of high (-medium) differentiation I-type granite. It may be related to the subduction of the Pacific plate to the South China plate.
【作者单位】： 中国地质调查局南京地质调查中心;
【基金】：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(1212011120833)资助
【分类号】：P588.121
本文编号：2329590
[Abstract]:Magmatic rocks are widely distributed in eastern Zhejiang, which is controlled by regional structure and distributes along the Yuyao-Lishui fault zone. Detailed geochronological and petrogeochemical studies of the Dongyuan granite body have been carried out in this paper. The Dongyuan rock body is mainly composed of monzogranite, quartz monosite and a small amount of granite. The LA-ICP-MS zircon U-Pb age of the main monzomorphic granite is 235.6 卤0.7 Ma (MSWD=0.97,2 蟽) and the granite is 238.1 卤0.8 Ma (MSWD=1.3,2 蟽). They all belong to the products of the Middle Triassic. The calc-alkaline granites of bauxite and quartz monzonite are characterized by high silicon (62.94%), and weak peraluminous calc-alkaline granites (75.29%). The characteristics of Na_2O K _ 2O _ (8.17) and K _ 2O _ (4.54) are 9.34% and 5.63% respectively. The fractionation of light and heavy rare earths is obvious, with strong Eu positive anomaly (未 Eu=0.94~2.43) and obvious depletion of high field strength element (HFSE) Nb,. Th,Hf, enriched light rare earth element (LREE) and large ion lithophile element (LILE) Rb, (LILE) Rb,) was relatively poor in Ba.. The magma originated from the partial melting of the thickened crust with arc property, and formed in the tectonic environment of the same collision to the post-collision stage, and the magma originated from the partial melting of the thickened crust with arc properties, and the rock mass is of high (-medium) differentiation I-type granite. It may be related to the subduction of the Pacific plate to the South China plate.
【作者单位】： 中国地质调查局南京地质调查中心;
【基金】：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(1212011120833)资助
【分类号】：P588.121
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，本文编号：2329590
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