浙东小雄破火山晚白垩世火山-侵入杂岩成因及岩浆演化  

Petrogenesis and magmatic process of Late Cretaceous volcano-intrusive complex from Xiaoxiong Caldrea, Eastern Zhejiang Province

作　　者：高丽 洪文涛[2] 杨祝良[2] 余明刚[2] GAO Li;HONG Wen-tao;YANG Zhu-liang;YU Ming-gang(Chinese Academy of Geological Sciences,Beijing 100037,China;Nanjing Center,China Geological Survey,Nanjing 210016,China)

机构地区：[1]中国地质科学院,北京100037 [2]中国地质调查局南京地质调查中心,南京210016

出　　处：《华东地质》2019年第3期161-169,共9页East China Geology

基　　金：国家重点研发计划专题“东南沿海中生代巨型火山构造成因与成矿(编号:2016YFC0600203)”;中国地质调查局“国家地质数据库建设与整合(编号:DD20179384)”;国家自然科学基金“磷灰石地球化学特征对酸性火山喷发及浅部岩浆房过程的指示:以福建永泰云破火山为例(编号:4170261)”项目联合资助

摘　　要：通过对浙东小雄破火山晚白垩世火山岩(流纹岩)-浅成侵入岩(正长斑岩)进行系统的岩相学和地球化学分析,探讨了火山-侵入杂岩的成因及岩浆演化过程。研究表明,小雄破火山晚白垩世流纹岩和正长斑岩经历了不同的结晶分异过程:流纹岩经历了碱性长石+磷灰石+锆石的分异;正长斑岩经历了普通辉石+磷灰石+Ti-Fe氧化物的分异。流纹岩和正长斑岩的母岩浆均起源于地壳物质的重熔,但各自有相对独立的演化过程,两者非同一岩浆房内某一岩浆连续分异的产物。推测在小雄破火山之下不同深度存在由多个子岩浆房构成的复杂岩浆系统,暗示东南沿海晚中生代火山-侵入杂岩中的侵入岩并不完全代表岩浆房下部的堆晶部分。Xiaoxiong Caldera is a well-outcropped Late Cretaceous volcanic apparatus situated in eastern seashore of Zhejiang Province,which indicates the end of Mesozoic large-scale silicic volcanic activity of southeastern China.Rhyolite and syenite-porphyry were two important rock types of the volcano-intrusive complex outcropped in the caldera.Petrologic and geochemical studies showed that both of them had experienced different crystal differentiation processes,of which the syenite-porphyry were controlled by Augi-te+Apatite+Ti-Fe oxide differentiation while the rhyolite controlled by the differentiation of alkaline feldspar+apatite+zircon.Parent magmas of the both were originated from the remelting of the source crustal material but each had undergone a relatively independent evolution process,rather than the continuous magmatic evolution in one magma chamber.It is inferred that there should have some sub-magmatic chambers at different depths which contributed an integrated magmatic system beneath the Xiaoxiong Caldera and resulted in the variety of rock type.Thus it suggests that the intrusive rocks of the Late Mesozoic volcano-intrusive complexes in Southeastern China may probably not be supposed to the accumulate part of the lower magma chamber.

关 键 词：结晶分异 火山-侵入杂岩 岩浆系统 小雄破火山 浙江 

分 类 号：P588.121[天文地球—岩石学]