岩浆混合作用:来自岩石包体的证据  

Magma Mingling:Evidence from Enclaves

作　　者：王德滋[1] 谢磊[1] 

机构地区：[1]南京大学地球科学系,南京210093

出　　处：《高校地质学报》2008年第1期16-21,共6页Geological Journal of China Universities

摘　　要：镁铁质岩浆与长英质岩浆之间的混合作用是导致壳幔混源花岗岩类形成的主要机制。暗色、细粒且具火成结构的岩石包体是指示岩浆混合作用存在的可靠证据。这些岩石包体具有下列特征:(1)包体常呈等轴状,表明包体岩浆曾以液态球滴状存在于寄主岩浆中;(2)由于基性岩浆温度恒高于酸性岩浆(温度超出约300℃),这类包体常具有淬冷边;(3)包体有时含有反向脉;(4)包体中能见到自寄主岩浆捕获的长石捕虏晶。进一步分析了三个典型的含暗色微粒包体的花岗质杂岩(平潭、普陀山、花山—姑婆山)研究实例,认为暗色微粒包体的形成,可用来自深部岩浆房的玄武质岩浆向浅部酸性岩浆房的注入作用来解释。The magma mingling between mafic magma and felsic magma is the primary mechanism responsible for the granitoids of crust-mantle mixed source. The dark colored, microgranular and igneous-texture enclaves provide reliable evidence that indicates the existence of magma mingling. These enclaves have the following characteristics： （1） the form of enclaves usually presents an equi-axed shape, which shows that enclave magma existed in the host magma with a globule liquid state; （2） since the temperature of basic magma is higher than acidic magma （temperature excess about 300℃）, this type of enclaves often has quenched margin; （3） the enclaves sometimes contain back veins; （4） feldspar xenocrysts captured from the host magma can be seen in the enclaves. Three typical granitic complexes （Pingtan, Putuoshan, Huashan-Guposhan） containing dark colored micro-granular enclaves are exemplified in this paper. The formation of dark colored microgranular enclaves can be explained by the injection of the basaltic magma from deep seated magma chamber toward hypabyssal acidic magma champer.

关 键 词：岩浆混合作用 包体 壳幔作用 

分 类 号：P588.1[天文地球—岩石学]