浙东晚中生代岩浆混合作用新证据:新昌儒岙岩石包体群的发现与地质意义  

A new case of Late Mesozoic magma mixing in eastern Zhejiang:Discovery of the Ruao enclave swarms,Xinchang County and its geological implication

作　　者：董传万[1] 沈忠悦[1] 杜振永[1] 杨永峰[1] 顾红艳[1] 

机构地区：[1]浙江大学地球科学系,浙江杭州310027

出　　处：《浙江大学学报（理学版）》2009年第2期224-230,242,共8页Journal of Zhejiang University（Science Edition）

基　　金：国家自然科学基金资助项目(批准号:40372035;40872051)

摘　　要：在浙江东部新昌儒岙花岗岩体中,新发现大量闪长岩-石英闪长岩包体.它们成群出现,大小不一,大部分呈圆或次圆形,具微细粒结构和冷凝边构造,并发育针状磷灰石.包体的分布,形态和结构构造特点表明,它们属淬冷包体.在化学上,岩石包体与寄主花岗岩及共生的辉绿岩都属亚碱性系列.微量元素协变关系证实,它们由玄武质岩浆和花岗质岩浆不均匀混合形成.新昌儒岙岩石包体群的发现和研究,为研究浙东地区晚中生代的岩浆混合作用、壳幔作用及花岗岩的成因提供了一个新的例证.A large number of dioritic, quartz dioritic enclaves are recently found in a restricted part of the Ruao granite, Xinchang County, East Zhejiang. The enclaves occurring in groups are generally round or sub-round with diameters from 20 cm to 1 m, and are often gray or dark-gray in color. Generally, there are clear boundaries between the enclaves and host granite, and some enclaves show fine-grained margins, i. e. , chilled margins and have needle like apatites. The characteristics of their distribution, shape, structure and texture show that they are quenched enclaves. Chemically, the enclaves and the host granite and diabase belong to sub alkaline series. The plots of trace elements of them testify that they are the products of the mechanical mixing between basaltic and granitic magmas. Therefore, this research provides a new case of Late Mesozoic magma mixing, crust mantle interaction and granite origins in East Zhejiang.

关 键 词：岩石包体 岩浆混合作用 晚中生代 浙东 新昌 

分 类 号：P588[天文地球—岩石学]