High-temperature inter-mineral potassium isotope fractionation in ultrapotassic and granitic rocks: Implications for the potassium isotopic compositions of arc magmas

doi:10.1016/j.chemgeo.2023.121770

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	High-temperature inter-mineral potassium isotope fractionation in ultrapotassic and granitic rocks: Implications for the potassium isotopic compositions of arc magmas
	Yang, Tinggen 1,3,5; Liu, Haiyang 1,5; Li, Yonghui 6; Xue, Ying-Yu 1,5; Li, Xiaoqiang 2; Wang, Kun 4; Sun, Wei-Dong 1,3,5
刊名	CHEMICAL GEOLOGY
	2023-12-20
卷号	641 页码:15
关键词	Potassium isotopes Inter-mineral potassium isotope fractionation First-principles calculation Amphibole Arc magma
ISSN号	0009-2541
DOI	10.1016/j.chemgeo.2023.121770
通讯作者	Liu, Haiyang(hyliu@qdio.ac.cn)
英文摘要	To constrain the mechanism and magnitude of inter-mineral K isotope fractionation during high-temperature magmatic processes, we conducted high-precision K isotope measurements on ultrapotassic and granitic rocks and mineral separates from the Qinling Orogenic Belt, China, as well as first-principles investigations of the corresponding K-bearing minerals. Our results show that the ultrapotassic rocks (-0.33 to-0.14%o) have considerably higher 841K than the primitive mantle (-0.42 +/- 0.08%o), confirming the previous conclusion that slab-derived fluids have contributed heavy K isotopic signatures to their mantle sources. Specifically, the K isotopic fractionation between biotite and microcline (A41Kbiotite-microcline =-0.11 to 0.05%o, with biotite and microcline ranging from-0.49 to-0.14%o and -0.48 to-0.12%o, respectively) agrees well with the calculated equilibrium isotopic fractionation scale. This evidence, together with the homogeneous mineral chemical com-positions, suggests equilibrium K isotopic fractionation between biotite and microcline. Notably, amphiboles (841K ranging from-0.41 to 0.48%o) have heterogeneous K isotopic compositions and are generally heavier than coexisting microcline and biotite. In addition, the determined K isotopic fractionation between amphibole/ plagioclase and microcline is inconsistent with the calculated results and is likely caused by the kinetic fractionation processes. To reveal the potential controls on the K isotopic compositions of arc magma, we utilized theoretical and measured K isotopic fractionation factors to model K isotopic fractionation behavior during amphibole crystallization. The results show that when A41Kamphibole-melt = 0.05%o, the fractional crystallization of amphibole shows negligible effect on the K isotopic composition of the residual melts. Even in the case of A41Kamphibole-melt = 0.24%o, fractional crystallization of amphibole exerts an insignificant control on the K isotopic composition of arc magma. Therefore, although amphibole may have heavier K isotopic compositions than the melts, its fractional crystallization may not distinctly decrease the K isotopic composition of residual melts.
资助项目	Scientific and Technological Innovation Program of the Laoshan Laboratory[LSKJ202204100] ; National Natural Science Foundation of China[92258303] ; National Natural Science Foundation of China[42373003] ; National Natural Science Foundation of China[41903006] ; Strategic Priority Research Program of the Chinese Academy of Sciences[XDB42020303] ; Strategic Priority Research Program of the Chinese Academy of Sciences[XDA22050103] ; State Key Laboratory of Marine Geology, Tongji University[MGK202305] ; State Key Laboratory for Mineral Deposits Research, Nanjing University[2023-LAMD-K05] ; Open Research Project from the State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences[GPMR202313]
WOS关键词	ALTERED OCEANIC-CRUST ; MC-ICP-MS ; EQUILIBRIUM FRACTIONATION ; K ISOTOPES ; COLLISION ; SR ; ND ; RATIOS ; MANTLE ; NORTH
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	ELSEVIER
WOS记录号	WOS:001097362800001
内容类型	期刊论文
源URL	[http://ir.qdio.ac.cn/handle/337002/183840]
专题	海洋研究所_深海极端环境与生命过程研究中心
通讯作者	Liu, Haiyang
作者单位	1.Chinese Acad Sci, Ctr Deep Sea Res, Inst Oceanol, Qingdao 266071, Peoples R China 2.China Univ Geosci Beijing, Inst Earth Sci, Beijing 100083, Peoples R China 3.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 4.McDonnell Ctr Space Sci, Dept Earth Environm & Planetary Sci, St. Louis, MO 63130 USA 5.Deep Sea Multidisciplinary Res Ctr, Laoshan Lab, Qingdao 266237, Peoples R China 6.Natl Supercomp Ctr Chengdu, Chengdu 610213, Sichuan, Peoples R China
推荐引用方式 GB/T 7714	Yang, Tinggen,Liu, Haiyang,Li, Yonghui,et al. High-temperature inter-mineral potassium isotope fractionation in ultrapotassic and granitic rocks: Implications for the potassium isotopic compositions of arc magmas[J]. CHEMICAL GEOLOGY,2023,641:15.
APA	Yang, Tinggen.,Liu, Haiyang.,Li, Yonghui.,Xue, Ying-Yu.,Li, Xiaoqiang.,...&Sun, Wei-Dong.(2023).High-temperature inter-mineral potassium isotope fractionation in ultrapotassic and granitic rocks: Implications for the potassium isotopic compositions of arc magmas.CHEMICAL GEOLOGY,641,15.
MLA	Yang, Tinggen,et al."High-temperature inter-mineral potassium isotope fractionation in ultrapotassic and granitic rocks: Implications for the potassium isotopic compositions of arc magmas".CHEMICAL GEOLOGY 641(2023):15.