Granitic magma mixing versus basaltic magma mixing: New viewpoints on granitic magma mixing process: some crucial questions on granite study

	Granitic magma mixing versus basaltic magma mixing: New viewpoints on granitic magma mixing process: some crucial questions on granite study
	Zhang Qi ; Pan GuoQiang ; Li ChengDong ; Jin WeiJun ; Jia XiuQin
刊名	ACTA PETROLOGICA SINICA
	2007-05-01
卷号	23 期号:5 页码:1141-1152
关键词	granites mixing mingling basalts viscosity geochemisty
ISSN号	1000-0569
文献子类	Article
英文摘要	How granitic magmas are mixed has become an interesting topic in recent years. Many workers are trying to interpret the variation of the composition of mixing granites with the different proportion of several end-members. However, we argue that such kind of mixing process for granites is uncommon and is unlikely happened in the field on the basis of a comparison of the properties of granite and basalt. The ability or competence that two granitic magmas can be mixed mainly depends on the viscosity and temperature of the magmas. The viscosity is related to the structure of SiO4 tetrahedron in the rocks. Granites in comparison with basalts have relatively high SiO2 contents and low temperature, and therefore granitic magmas have low competence to be mixed with each other. Unlike the mixing process of basaltic magmas, granitic magmas are more likely mingling, rather than mixing, with each other. There is rare example for the mixing of granitic magmas, the only case is high-Mg andesite or high-Mg adakite formed by mixing of adakite and upwelling mantle. Many workers argued that mafic microgranular enclaves (MME) in granites are the direct evidence for the mixing of granitic magmas. However, we argue that it is an exact evidence for that granitic magmas are difficult to be mixed with these mafic enclaves. Granitic rocks are actually heterogeneous in compositions because they have derived from heterogeneous sources with complicated melting processes. It is thus unlikely to assume the original granites are homogeneous. The variation of compositions of granites and the correlation of elements in Harker diagrams are mainly the results of heterogeneity of sources, rather than mixing or differentiation processes. Usually magmas tend to be homogeneous by mixing in magma conduits on the way upwelling to emplacement and at the same time they may become heterogeneous with the crustal contamination. However, grantic magmas are hard to be as homogeneous as basaltic magmas in this process because of their higher viscosity than that of basaltic magmas. Therefore, not only geochernical compositions of granites but also their physical properties should be considered in the study of the origin of granites, and it should be cautious when using geochernical data to discriminate the origin and tectonic environment of granites.
WOS关键词	LACHLAN FOLD BELT ; CRUSTAL ARCHITECTURE ; PETROGENETIC MODELS ; HYBRID GRANITOIDS ; TECTONIC MODELS ; DYNAMICS ; COMPLEX ; DIFFERENTIATION ; CONSTRAINTS ; INFERENCES
WOS研究方向	Geology
语种	英语
出版者	SCIENCE CHINA PRESS
WOS记录号	WOS:000248135100026
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/67896]
专题	中国科学院地质与地球物理研究所
通讯作者	Zhang Qi
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China 2.Nanjing Univ, Dept Earth Sci, Nanjing 210093, Peoples R China 3.Tianjin Inst Geol & Mineral Resources, Tianjin 300170, Peoples R China 4.Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China
推荐引用方式 GB/T 7714	Zhang Qi,Pan GuoQiang,Li ChengDong,et al. Granitic magma mixing versus basaltic magma mixing: New viewpoints on granitic magma mixing process: some crucial questions on granite study[J]. ACTA PETROLOGICA SINICA,2007,23(5):1141-1152.
APA	Zhang Qi,Pan GuoQiang,Li ChengDong,Jin WeiJun,&Jia XiuQin.(2007).Granitic magma mixing versus basaltic magma mixing: New viewpoints on granitic magma mixing process: some crucial questions on granite study.ACTA PETROLOGICA SINICA,23(5),1141-1152.
MLA	Zhang Qi,et al."Granitic magma mixing versus basaltic magma mixing: New viewpoints on granitic magma mixing process: some crucial questions on granite study".ACTA PETROLOGICA SINICA 23.5(2007):1141-1152.