【摘要】：浙東地區(qū)巖漿巖廣泛分布,受區(qū)域構(gòu)造控制較明顯,總體沿北東向余姚-麗水?dāng)嗔褞Х植�。本文�?duì)東園花崗巖體開展了詳細(xì)的年代學(xué)和巖石地球化學(xué)研究。東園巖體主要由二長(zhǎng)花崗巖、石英二長(zhǎng)巖和少量花崗巖組成,主巖體二長(zhǎng)花崗巖的LA-ICP-MS鋯石U-Pb年齡為235.6±0.7 Ma(MSWD=0.97,2σ),花崗巖為238.1±0.8 Ma(MSWD=1.3,2σ),均屬中三疊世產(chǎn)物。二長(zhǎng)花崗巖和石英二長(zhǎng)巖為準(zhǔn)鋁質(zhì)-弱過鋁質(zhì)的鈣堿性花崗巖,具高硅(62.94%~75.29%)、富堿(Na_2O+K_2O=8.17%~9.34%)且富鉀(K_2O=4.54%~5.63%)的特征,輕重稀土分餾明顯,具有較強(qiáng)的Eu正異常(δEu=0.94~2.43),明顯虧損高場(chǎng)強(qiáng)元素(HFSE)Nb、P、Ti,而相對(duì)富集Th、Hf,富集輕稀土元素(LREE)和大離子親石元素(LILE)Rb,相對(duì)貧Ba。巖體屬高(-中等)分異I型花崗巖,巖漿來源于具弧屬性的加厚地殼部分熔融,形成于同碰撞向后碰撞階段轉(zhuǎn)變的大地構(gòu)造環(huán)境,可能與太平洋板塊向華南板塊俯沖作用事件有關(guān)。
[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 鹵0.7 Ma (MSWD=0.97,2 蟽) and the granite is 238.1 鹵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.
【作者單位】： 中國(guó)地質(zhì)調(diào)查局南京地質(zhì)調(diào)查中心;
【基金】：中國(guó)地質(zhì)調(diào)查局“浙江1∶50000崇仁鎮(zhèn)、長(zhǎng)樂鎮(zhèn)、嶺口鎮(zhèn)、巍山鎮(zhèn)幅區(qū)域地質(zhì)調(diào)查”項(xiàng)目(1212011120833)資助
【分類號(hào)】：P588.121

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