Chromite-induced magnesium isotope fractionation during mafic magma differentiation

doi:10.1016/j.scib.2017.11.001

	Chromite-induced magnesium isotope fractionation during mafic magma differentiation
	Su, Ben-Xun 1,2,3; Hu, Yan 2; Teng, Fang-Zhen 2; Qin, Ke-Zhang 1,3; Bai, Yang 1,3; Sakyi, Patrick Asamoah 4; Tang, Dong-Mei 1
刊名	SCIENCE BULLETIN
	2017-11-30
卷号	62 期号:22 页码:1538-1546
关键词	Mg Isotopes Alaskan-type Intrusion Arc Magmatism Magma Differentiation Chromite
ISSN号	2095-9273
DOI	10.1016/j.scib.2017.11.001
文献子类	Article
英文摘要	To better understand the mechanism of Mg isotopic variation in magma systems, here we report high precision Mg isotopic data of 17 bulk rock samples including dunite, clinopyroxenite, hornblendite and gabbro and 10 pairs of dunite-hosted olivine and chromite separates from the well-characterized Alaskan-type Xiadong intrusion in NW China, which formed by continuous and high degree of lithological differentiation from mafic magmas. Chromite separates have highly variable delta Mg-26 values from -0.10% to 0.40%, and are consistently heavier than coexisting olivine separates (-0.39% to -0.15%). Both mineral delta Mg-26 values and the degrees of inter-mineral fractionation are well correlated with geochemical indicators of magma differentiation, indicating that these inter-sample and inter-mineral Mg isotope fractionations are caused by magma evolution. The delta Mg-26 values range from -0.20% to -0.02% in the dunite, -0.43% in the clinopyroxenite, -0.43% to -0.28% in the hornblendite, 0.18% in the chromite-bearing hornblendite, and -0.56% to -0.16% in the gabbro. The Mg isotopic variations in different types of rocks are closely related to fractional crystallization and accumulation of different proportions of oxides vs. silicates. Chromite crystallization and accumulation is the most important factor in controlling Mg isotope fractionation during the formation of the Xiadong intrusion. Compared to basaltic and granitic magmas, differentiation of the Alaskan-type intrusions occurs at a relatively high oxygen fugacity, which favors chromite crystallization and consequently significant Mg isotope fractionations at both mineral and whole-rock scales. Therefore, Mg isotope systematics can be used to trace the degree of magma differentiation and related-mineralization. (C) 2017 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.
WOS关键词	ALASKAN-TYPE COMPLEX ; NORTH CHINA CRATON ; NW CHINA ; CONTINENTAL BASALTS ; CONSTRAINTS ; ORIGIN ; MANTLE ; OLIVINE ; DIFFUSION ; SPINEL
WOS研究方向	Science & Technology - Other Topics
语种	英语
出版者	SCIENCE PRESS
WOS记录号	WOS:000416211500010
资助机构	National Key R&D Program of China(2017YF0601204) ; National Key R&D Program of China(2017YF0601204) ; National Natural Science Foundation of China(41522203) ; National Natural Science Foundation of China(41522203) ; National Science Foundation of United States(EAR-1747706) ; National Science Foundation of United States(EAR-1747706) ; National Key R&D Program of China(2017YF0601204) ; National Key R&D Program of China(2017YF0601204) ; National Natural Science Foundation of China(41522203) ; National Natural Science Foundation of China(41522203) ; National Science Foundation of United States(EAR-1747706) ; National Science Foundation of United States(EAR-1747706) ; National Key R&D Program of China(2017YF0601204) ; National Key R&D Program of China(2017YF0601204) ; National Natural Science Foundation of China(41522203) ; National Natural Science Foundation of China(41522203) ; National Science Foundation of United States(EAR-1747706) ; National Science Foundation of United States(EAR-1747706) ; National Key R&D Program of China(2017YF0601204) ; National Key R&D Program of China(2017YF0601204) ; National Natural Science Foundation of China(41522203) ; National Natural Science Foundation of China(41522203) ; National Science Foundation of United States(EAR-1747706) ; National Science Foundation of United States(EAR-1747706)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/82168]
专题	中国科学院地质与地球物理研究所
通讯作者	Su, Ben-Xun
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Mineral Resources, Beijing 100029, Peoples R China 2.Univ Washington, Dept Earth & Space Sci, Seattle, WA 98195 USA 3.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 4.Univ Ghana, Dept Earth Sci, LG 5, Legon, Accra, Ghana
推荐引用方式 GB/T 7714	Su, Ben-Xun,Hu, Yan,Teng, Fang-Zhen,et al. Chromite-induced magnesium isotope fractionation during mafic magma differentiation[J]. SCIENCE BULLETIN,2017,62(22):1538-1546.
APA	Su, Ben-Xun.,Hu, Yan.,Teng, Fang-Zhen.,Qin, Ke-Zhang.,Bai, Yang.,...&Tang, Dong-Mei.(2017).Chromite-induced magnesium isotope fractionation during mafic magma differentiation.SCIENCE BULLETIN,62(22),1538-1546.
MLA	Su, Ben-Xun,et al."Chromite-induced magnesium isotope fractionation during mafic magma differentiation".SCIENCE BULLETIN 62.22(2017):1538-1546.