中国科学院机构知识库网格
Chinese Academy of Sciences Institutional Repositories Grid
Potassium isotopic composition of low-temperature altered oceanic crust and its impact on the global K cycle

文献类型:期刊论文

作者Liu, Haiyang1,2,3,4,5; Xue, Ying-Yu1,2,3; Zhang, Guoliang1,2,3; Sun, Wei-Dong1,2,3,6; Tian, Zhen4,5; Tuller-Ross, Brenna4,5; Wang, Kun4,5
刊名GEOCHIMICA ET COSMOCHIMICA ACTA
出版日期2021-10-15
卷号311页码:59-73
关键词K isotopes K oceanic budget Low temperature seafloor alteration IODP U1365 and U1368 Global K cycle Mantle heterogeneity
ISSN号0016-7037
DOI10.1016/j.gca.2021.08.001
通讯作者Liu, Haiyang(hyliu@qdio.ac.cn) ; Wang, Kun(wangkun@wustl.edu)
英文摘要To constrain the behavior of K isotopes during the low-temperature alteration of oceanic crust and reveal its impact on the global K cycle, we measured the K isotopic compositions of 49 fresh and altered basalts recovered from the Integrated Ocean Drilling Program (IODP) Sites U1365 (similar to 100 Ma) and U1368 (similar to 13.5 Ma) in the South Pacific Ocean. The measured basalts representing the uppermost oceanic crust have been subjected to low-temperature (<150 degrees C) alteration of different types and intensities as reflected by different secondary mineral modal abundances and element mobility. Both Sites have remarkably low sedimentation rates (0.71 and 1.1 m/Myr, respectively). The altered basalts from both Sites show higher K2O contents and K/Nb ratios than fresh basalts, suggesting the addition of K during low-temperature alteration. The measured delta K-41 values of the altered basalts vary over a large range (-0.76 parts per thousand to -0.17 parts per thousand) compared to unaltered basalts, indicating significant K isotopic fractionation during low-temperature alteration of the oceanic crust. We propose that the K isotopic characteristics of the altered basalts were caused by the combined effects of equilibrium and kinetic isotopic fractionations between seawater and alteration minerals during the incorporation and adsorption of K into alteration minerals. A weighted average delta K-41 value of -0.40 +/- 0.33 parts per thousand (2sd) is given for the low-temperature altered oceanic crust (AOC) at Sites U1365 and U1368, which is indistinguishable from the fresh N-MORB value (-0.44 +/- 0.17 parts per thousand), but significantly lower than its K source, i.e., seawater {delta K-41 = +0.12 +/- 0.07 parts per thousand, 2sd). Therefore, low-temperature AOC serves as an important sink for K and is a cause for the heavy K isotopic composition of seawater. In addition, the heterogeneous K isotopic compositions of the low-temperature AOC, together with large scale fractionation during various crustal processes, further highlights the utility of the K isotope system to trace subducted crustal materials. (C) 2021 Elsevier Ltd. All rights reserved.
资助项目Chinese Academy of Sciences[XDB42020303] ; National Natural Science Foundation of China[91858206] ; National Natural Science Foundation of China[41903006] ; China Postdoctoral Science Foundation[Y9KY06110H] ; China Postdoctoral Science Foundation[2020T130656] ; AoShan Talents Cultivation Program - Qingdao National Laboratory for Marine Science and Technology[2017ASTCP-OS07]
WOS研究方向Geochemistry & Geophysics
语种英语
WOS记录号WOS:000693337600005
出版者PERGAMON-ELSEVIER SCIENCE LTD
源URL[http://ir.qdio.ac.cn/handle/337002/176382]  
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; Wang, Kun
作者单位1.Chinese Acad Sci, Ctr Deep Sea Res, Inst Oceanol, Qingdao 266071, Peoples R China
2.Pilot Natl Lab Marine Sci & Technol Qingdao, Lab Marine Mineral Resources, Qingdao 266237, Peoples R China
3.Chinese Acad Sci, Ctr Ocean Megasci, Qingdao 266071, Peoples R China
4.Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA
5.Washington Univ, McDonnell Ctr Space Sci, St Louis, MO 63130 USA
6.Univ Chinese Acad Sci, Beijing 100049, Peoples R China
推荐引用方式
GB/T 7714
Liu, Haiyang,Xue, Ying-Yu,Zhang, Guoliang,et al. Potassium isotopic composition of low-temperature altered oceanic crust and its impact on the global K cycle[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2021,311:59-73.
APA Liu, Haiyang.,Xue, Ying-Yu.,Zhang, Guoliang.,Sun, Wei-Dong.,Tian, Zhen.,...&Wang, Kun.(2021).Potassium isotopic composition of low-temperature altered oceanic crust and its impact on the global K cycle.GEOCHIMICA ET COSMOCHIMICA ACTA,311,59-73.
MLA Liu, Haiyang,et al."Potassium isotopic composition of low-temperature altered oceanic crust and its impact on the global K cycle".GEOCHIMICA ET COSMOCHIMICA ACTA 311(2021):59-73.

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来源:海洋研究所

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