The progress and prospects of potassium stable isotopes in hydrogeochemistry
-
摘要: 地表硅酸盐矿物风化通常是水体中钙、镁、钠、钾等元素的重要来源,然而相比于水体中的钙、镁和钠,前人对钾的水文地球化学行为的认识仍十分有限。表生地球化学领域最新研究证明风化、吸附等多种水岩反应伴随着较大的钾同位素分馏,表明钾同位素技术可以用于示踪地下水中钾的来源及迁移转化。文章通过系统总结上地壳、水圈和其他地表储库(植物、肥料)的钾同位素组成,发现水圈普遍比大陆上地壳富集41K,为识别地下水的钾来源提供了基础;通过总结钾同位素在常见的水岩作用过程(硅酸盐矿物溶解、次生黏土形成、吸附作用、离子交换反应)中的分馏行为,发现硅酸盐矿物溶解分馏有限,次生黏土矿物形成引起水体富集41K,表面吸附和离子交换使水体富集39K,不同水岩反应中K同位素行为差异为示踪地下水中钾的迁移转化过程提供了基础;列举了应用钾同位素示踪硅酸盐岩风化和水体污染的最新研究成果。由于钾同位素是硅酸盐岩风化的良好示踪剂,可以利用钾同位素揭示CO2较充足含水层中钾元素释放及迁移转化机理;由于表面吸附和离子交换控制的钾同位素分馏方向与风化控制的钾同位素分馏方向不同,可以利用钾同位素识别出地下水循环过程中多种水岩反应对钾迁移转化的共同控制。在此基础上,本文对钾同位素在水文地球化学领域的应用进行了展望:(1)开展对研究区多端元控制下地下水钾来源贡献的研究;(2)开展地下水漫长循环过程中钾迁移转化的定量研究;(3)联合使用多种同位素示踪碳循环相关的过程。Abstract: Chemical weathering of silicate minerals is an important source for Ca, Mg, Na and K, however, in comparison with other major elements (e.g., Ca, Mg and Na) in waters, how K behaves during water-rock interaction remains poorly constrained. Recent studies have shown that large K isotopic fractionation could occur during various processes of low-temperature water-rock interaction, making K isotopes gradually become a powerful tracer for K elemental cycle. This overview summarizes (1) K isotopic compositions of major reservoirs at the Earth’s surface, including upper continental crust, hydrosphere and other reservoirs (plants and fertilizers), (2) the magnitudes and mechanisms of K isotope fractionation during common water-rock interaction processes (i.e., silicate dissolution, secondary mineral formation, adsorption, cation exchange), and (3) The latest studies that applied K isotopes to trace silicate weathering and water pollution. Based on the discussion above, we conclude with an outlook on future K isotopic studies in the field of hydrogeochemistry.
-
Key words:
- K isotopes /
- water-rock interaction /
- isotope fractionation /
- adsorption /
- chemical weathering /
- pollution tracing
-
图 2 花岗岩剖面δ41K与CIA关系图。
注:风化花岗岩数据来自Teng等[15]。
Figure 2. The relationship between δ41K and CIA for weathered granites.
图 3 河流δ41K与CIA关系图 (a);河流δ41K与WI关系图 (b)。
注:河水数据来自Li等[19]
Figure 3. Cross-plots of δ41K in riverine dissolved loads versus CIA in river sediments (a) and WI (b).
-
[1] BERNER E K, BERNER R A. Global environment: water, air, and geochemical cycles[M]. Princeton: Princeton University Press, 2012. [2] WANG K,LI W,LI S,et al. Geochemistry and Cosmochemistry of potassium stable isotopes[J]. Geochemistry,2021,81(3):125786. doi: 10.1016/j.chemer.2021.125786 [3] 王昆,李伟强,李石磊. 钾稳定同位素研究综述[J]. 地学前缘,2020,27(3):104 − 122. [WANG Kun,Li Weiqiang,Li Shilei. Stable potassium isotope geochemistry and cosmochemistry[J]. Earth Science Frontiers,2020,27(3):104 − 122. doi: 10.13745/j.esf.sf.2020.4.5 [4] WHITE A F,SCHULZ M S,LOWENSTERN J B,et al. The ubiquitous nature of accessory calcite in granitoid rocks:implications for weathering,solute evolution,and petrogenesis[J]. Geochimica et Cosmochimica Acta,2005,69(6):1455 − 1471. doi: 10.1016/j.gca.2004.09.012 [5] RUDNICK R, GAO S. Composition of the Continental Crust[J]. Treatise on Geochemistry (Second Edition), 2014. [6] GAILLARDET J,VIERS J,DUPRé B. Trace elements in river waters[J]. Treatise on Geochemistry (Second Edition),2014,5(Suppl 1):195 − 235. [7] HUFF G, WOODS L, MOKTAN H, et al. , 2012. Geochemistry of groundwater and springwater in the Paskapoo formation and overlying glacial drift, south‐central Alberta, ERCB/Alberta Geological Survey Open-File Report. Energy Resources Conservation Board. [8] SPARKS D L. Environmental soil chemistry[M]. Elsevier, 2003. [9] LI W,BEARD B L,LI S. Precise measurement of stable potassium isotope ratios using a single focusing collision cell multi-collector ICP-MS[J]. Journal of Analytical Atomic Spectrometry,2016,31(4):1023 − 1029. doi: 10.1039/C5JA00487J [10] LI X,HAN G,ZHANG Q,et al. An optimal separation method for high-precision K isotope analysis by using MC-ICP-MS with a dummy bucket[J]. Journal of Analytical Atomic Spectrometry,2020,35(7):1330 − 1339. doi: 10.1039/D0JA00127A [11] MORGAN L E,RAMOS D P S,DAVIDHEISER-KROLL B,et al. High-precision 41K/39K measurements by MC-ICP-MS indicate terrestrial variability of δ41K[J]. Journal of Analytical Atomic Spectrometry,2018,33(2):175 − 186. doi: 10.1039/C7JA00257B [12] GARNER E L,MURPHY T J,GRAMLICH J W,et al. Absolute isotopic abundance ratios and the atomic weight of a reference sample of potassium[J]. Journal of Research of the National Bureau of Standards Physics Chemistry,1975,79A(6):713 − 725. [13] WANG K,JACOBSEN S B. An estimate of the Bulk Silicate Earth potassium isotopic composition based on MC-ICPMS measurements of basalts[J]. Geochimica et Cosmochimica Acta,2016,178:223 − 232. doi: 10.1016/j.gca.2015.12.039 [14] HU Y,CHEN X-Y,XU Y-K,et al. High-precision analysis of potassium isotopes by HR-MC-ICPMS[J]. Chemical Geology,2018,493:100 − 108. doi: 10.1016/j.chemgeo.2018.05.033 [15] TENG F-Z,HU Y,MA J-L,et al. Potassium isotope fractionation during continental weathering and implications for global K isotopic balance[J]. Geochimica et Cosmochimica Acta,2020,278:261 − 271. doi: 10.1016/j.gca.2020.02.029 [16] CHEN H,TIAN Z,TULLER-ROSS B,et al. High-precision potassium isotopic analysis by MC-ICP-MS:An inter-laboratory comparison and refined K atomic weight[J]. Journal of Analytical Atomic Spectrometry,2019,34(1):160 − 171. doi: 10.1039/C8JA00303C [17] HUANG T-Y,TENG F-Z,RUDNICK R L,et al. Heterogeneous potassium isotopic composition of the upper continental crust[J]. Geochimica et Cosmochimica Acta,2020,278:122 − 136. doi: 10.1016/j.gca.2019.05.022 [18] MOYNIER F,HU Y,WANG K,et al. Potassium isotopic composition of various samples using a dual-path collision cell-capable multiple-collector inductively coupled plasma mass spectrometer,Nu instruments Sapphire[J]. Chemical Geology,2021,571:120144. doi: 10.1016/j.chemgeo.2021.120144 [19] LI S,LI W,BEARD B L,et al. K isotopes as a tracer for continental weathering and geological K cycling[J]. Proceedings of the National Academy of Sciences,2019,116(18):8740 − 8745. doi: 10.1073/pnas.1811282116 [20] LI X,HAN G,LIU M,et al. Potassium and its isotope behaviour during chemical weathering in a tropical catchment affected by evaporite dissolution[J]. Geochimica et Cosmochimica Acta,2022,316:105 − 121. doi: 10.1016/j.gca.2021.10.009 [21] WANG X-K,LIU X-M,CHEN H. An efficient method for high-precision potassium isotope analysis in carbonate materials[J]. Journal of Analytical Atomic Spectrometry,2022,37(11):2410 − 2419. doi: 10.1039/D2JA00170E [22] LI W,LIU X-M,WANG K,et al. Potassium phases and isotopic composition in modern marine biogenic carbonates[J]. Geochimica et Cosmochimica Acta,2021,304:364 − 380. doi: 10.1016/j.gca.2021.04.018 [23] LI W,LIU X-M,WANG K,et al. Soil potassium isotope composition during four million years of ecosystem development in Hawai ‘i[J]. Geochimica et Cosmochimica Acta,2022,332:57 − 77. doi: 10.1016/j.gca.2022.06.025 [24] LI W,LIU X-M,HU Y,et al. Potassium isotope fractionation during chemical weathering in humid and arid Hawaiian regoliths[J]. Geochimica et Cosmochimica Acta,2022,333:39 − 55. doi: 10.1016/j.gca.2022.07.001 [25] LI W,LIU X-M,HU Y,et al. Potassium isotopic fractionation in a humid and an arid soil–plant system in Hawai ‘i[J]. Geoderma,2021,400:115219. doi: 10.1016/j.geoderma.2021.115219 [26] SUN Y,TENG F-Z,HU Y,et al. Tracing subducted oceanic slabs in the mantle by using potassium isotopes[J]. Geochimica et Cosmochimica Acta,2020,278:353 − 360. doi: 10.1016/j.gca.2019.05.013 [27] HILLE M,HU Y,HUANG T-Y,et al. Homogeneous and heavy potassium isotopic composition of global oceans[J]. Science Bulletin,2019,64(23):1740 − 1742. doi: 10.1016/j.scib.2019.09.024 [28] WANG K,CLOSE H G,TULLER-ROSS B,et al. Global average potassium isotope composition of modern seawater[J]. ACS Earth Space Chemistry,2020,4(7):1010 − 1017. doi: 10.1021/acsearthspacechem.0c00047 [29] ZHENG X-Y,CHEN X-Y,DING W,et al. High precision analysis of stable potassium (K) isotopes by the collision cell MC-ICP-MS “Sapphire” and a correction method for concentration mismatch[J]. Journal of Analytical Atomic Spectrometry,2022,37:1273 − 1287. doi: 10.1039/D2JA00078D [30] WANG K,PEUCKER-EHRENBRINK B,CHEN H,et al. Dissolved potassium isotopic composition of major world rivers[J]. Geochimica et Cosmochimica Acta,2021,294:145 − 159. doi: 10.1016/j.gca.2020.11.012 [31] RAMOS D P S,MORGAN L E,LLOYD N S,et al. Reverse weathering in marine sediments and the geochemical cycle of potassium in seawater:Insights from the K isotopic composition (41K/39K) of deep-sea pore-fluids[J]. Geochimica et Cosmochimica Acta,2018,236:99 − 120. doi: 10.1016/j.gca.2018.02.035 [32] 姬韬韬. 砂岩含水层中锂钾元素循环与同位素变化规律——以鄂尔多斯盆地为例[D]. 北京: 中国地质大学 (北京), 2022 JI Taotao. Elemental cycling and isotopic variations of lithium and potassium in sandstone aquifers: A case study in the Ordos Basin[D]. Beijing: China University of Geosciences (Beijing), 2022. (in Chinese with English Abstract) [33] CHRISTENSEN J N,QIN L,BROWN S T,et al. Potassium and calcium isotopic fractionation by plants (soybean [Glycine max],rice [Oryza sativa],and wheat [Triticum aestivum])[J]. ACS Earth Space Chemistry,2018,2(7):745 − 752. doi: 10.1021/acsearthspacechem.8b00035 [34] LI W. Vital effects of K isotope fractionation in organisms:observations and a hypothesis[J]. Acta Geochimica,2017,36(3):374 − 378. doi: 10.1007/s11631-017-0167-1 [35] QU R, HAN G. Potassium Isotopes in Herbaceous Plants: A Potential New Tool for C3 and C4 Plant Research[J]. 2022, 127 (11): e2021JG006682. [36] QU R, HAN G. Potassium isotopes of fertilizers as potential markers of anthropogenic input in ecosystems[J]. Environmental Chemistry Letters, 2022: 1 − 5. [37] WALKER J C,HAYS P,KASTING J F. A negative feedback mechanism for the long‐term stabilization of Earth's surface temperature[J]. Journal of Geophysical Research:Oceans,1981,86(C10):9776 − 9782. doi: 10.1029/JC086iC10p09776 [38] VIERS J,OLIVA P,DANDURAND J-L,et al. Chemical weathering rates,CO2 consumption,and control parameters deduced from the chemical composition of rivers[J]. Treatise on geochemistry,2003,5:661 − 686. [39] GAILLARDET J,DUPRé B,LOUVAT P,et al. Global silicate weathering and CO2 consumption rates deduced from the chemistry of large rivers[J]. Chemical Geology,1999,159(1 − 4):3 − 30. doi: 10.1016/S0009-2541(99)00031-5 [40] SOULET G,HILTON R G,GARNETT M H,et al. Temperature control on CO2 emissions from the weathering of sedimentary rocks[J]. Nature Geoscience,2021,14(9):665 − 671. doi: 10.1038/s41561-021-00805-1 [41] REGNIER P,RESPLANDY L,NAJJAR R G,et al. The land-to-ocean loops of the global carbon cycle[J]. Nature,2022,603(7901):401 − 410. doi: 10.1038/s41586-021-04339-9 [42] TENG F-Z,LI W-Y,RUDNICK R L,et al. Contrasting lithium and magnesium isotope fractionation during continental weathering[J]. Earth and Planetary Science Letters,2010,300(1-2):63 − 71. doi: 10.1016/j.jpgl.2010.09.036 [43] TIPPER E T,LEMARCHAND E,HINDSHAW R S,et al. Seasonal sensitivity of weathering processes:Hints from magnesium isotopes in a glacial stream[J]. Chemical Geology,2012,312:80 − 92. [44] POGGE VON STRANDMANN P A E,PORCELLI D,JAMES R H,et al. Chemical weathering processes in the Great Artesian Basin:Evidence from lithium and silicon isotopes[J]. Earth and Planetary Science Letters,2014,406:24 − 36. doi: 10.1016/j.jpgl.2014.09.014 [45] CHEN B-B,LI S-L,POGGE VON STRANDMANN P A E,et al. Calcium isotopes tracing secondary mineral formation in the high-relief Yalong River Basin,Southeast Tibetan Plateau[J]. Science of The Total Environment,2022,827:154315. doi: 10.1016/j.scitotenv.2022.154315 [46] DELLINGER M,GAILLARDET J,BOUCHEZ J,et al. Riverine Li isotope fractionation in the Amazon River basin controlled by the weathering regimes[J]. Geochimica et Cosmochimica Acta,2015,164:71 − 93. doi: 10.1016/j.gca.2015.04.042 [47] JACOBSON A D,ANDREWS M G,LEHN G O,et al. Silicate versus carbonate weathering in Iceland:New insights from Ca isotopes[J]. Earth Planetary Science Letters,2015,416:132 − 142. doi: 10.1016/j.jpgl.2015.01.030 [48] POGGE VON STRANDMANN P A E,BURTON K W,JAMES R H,et al. Assessing the role of climate on uranium and lithium isotope behaviour in rivers draining a basaltic terrain[J]. Chemical Geology,2010,270(1 − 4):227 − 239. doi: 10.1016/j.chemgeo.2009.12.002 [49] RYU J-S,JACOBSON A D,HOLMDEN C,et al. The major ion,δ44/40Ca,δ44/42Ca,and δ26/24Mg geochemistry of granite weathering at pH=1 and T=25°C:power-law processes and the relative reactivity of minerals[J]. Geochimica et Cosmochimica Acta,2011,75(20):6004 − 6026. doi: 10.1016/j.gca.2011.07.025 [50] LI W,LIU X-M,WANG K,et al. Lithium and potassium isotope fractionation during silicate rock dissolution:An experimental approach[J]. Chemical Geology,2021,568:120142. doi: 10.1016/j.chemgeo.2021.120142 [51] LI W,LIU X-M,HU Y,et al. Potassium isotopic fractionation during clay adsorption[J]. Geochimica et Cosmochimica Acta,2021,304:160 − 177. doi: 10.1016/j.gca.2021.04.027 [52] ZENG H,ROZSA V F,NIE N X,et al. Ab initio calculation of equilibrium isotopic fractionations of potassium and rubidium in minerals and water[J]. ACS Earth Space Chemistry,2019,3(11):2601 − 2612. doi: 10.1021/acsearthspacechem.9b00180 [53] POKROVSKY O S,VIERS J,FREYDIER R. Zinc stable isotope fractionation during its adsorption on oxides and hydroxides[J]. Journal of Colloid Interface Science,2005,291(1):291. [54] BRYAN A L,DONG S,WILKES E B,et al. Zinc isotope fractionation during adsorption onto Mn oxyhydroxide at low and high ionic strength[J]. Geochimica et Cosmochimica Acta,2015,157:182 − 197. doi: 10.1016/j.gca.2015.01.026 [55] WASYLENKI L E,SWIHART J W,ROMANIELLO S J. Cadmium isotope fractionation during adsorption to Mn oxyhydroxide at low and high ionic strength[J]. Geochimica et Cosmochimica Acta,2014,140:212 − 226. doi: 10.1016/j.gca.2014.05.007 [56] LI W,LIU X-M. Experimental investigation of lithium isotope fractionation during kaolinite adsorption:Implications for chemical weathering[J]. Geochimica et Cosmochimica Acta,2020,284:156 − 172. doi: 10.1016/j.gca.2020.06.025 [57] SPIVAK-BIRNDORF L J,WANG S-J,BISH D L,et al. Nickel isotope fractionation during continental weathering[J]. Chemical Geology,2018,476:316 − 326. doi: 10.1016/j.chemgeo.2017.11.028 [58] HUANG K-J,TENG F-Z,WEI G-J,et al. Adsorption-and desorption-controlled magnesium isotope fractionation during extreme weathering of basalt in Hainan Island,China[J]. Earth Planetary Science Letters,2012,359:73 − 83. [59] GRIFFIOEN J. Potassium adsorption ratios as an indicator for the fate of agricultural potassium in groundwater[J]. Journal of Hydrology,2001,254(1 − 4):244 − 254. doi: 10.1016/S0022-1694(01)00503-0 [60] CEAZAN M L,THURMAN E M,SMITH R L. Retardation of ammonium and potassium transport through a contaminated sand and gravel aquifer:the role of cation exchange[J]. Environmental Science Technology,1989,23(11):1402 − 1408. doi: 10.1021/es00069a012 [61] TEPPEN B J,MILLER D M. Hydration energy determines isovalent cation exchange selectivity by clay minerals[J]. Soil Science Society of America Journal,2006,70(1):31 − 40. doi: 10.2136/sssaj2004.0212 [62] RUIZ PESTANA L,KOLLURI K,HEAD-GORDON T,et al. Direct exchange mechanism for interlayer ions in non-swelling clays[J]. Environmental Science & Technology,2017,51(1):393 − 400. [63] TAYLOR T I,UREY H C. Fractionation of the lithium and potassium isotopes by chemical exchange with zeolites[J]. The Journal of Chemical Physics,1938,6(8):429 − 438. doi: 10.1063/1.1750288 [64] KAWADA K,OL T,HOSOE M,et al. Fractionation of potassium isotopes in cation-exchange chromatography[J]. Journal of Chromatography A,1991,538(2):355 − 364. doi: 10.1016/S0021-9673(01)88856-7 [65] 苟龙飞,金章东,贺茂勇. 锂同位素示踪大陆风化:进展与挑战[J]. 地球环境学报,2017,8(2):89 − 102. [GOU Longfei,Jin Zhangdong,He Maoyong. Using lithium isotopes traces continental weathering:Progresses and challenges[J]. Journal of Earth Environment,2017,8(2):89 − 102. doi: 10.7515/JEE201702001 [66] CHETELAT B,LIU C Q,ZHAO Z Q,et al. Geochemistry of the dissolved load of the Changjiang Basin rivers:anthropogenic impacts and chemical weathering[J]. Geochimica et Cosmochimica Acta,2008,72(17):4254 − 4277. doi: 10.1016/j.gca.2008.06.013 [67] ROY S,GAILLARDET J,ALLEGRE C. Geochemistry of dissolved and suspended loads of the Seine river,France:anthropogenic impact,carbonate and silicate weathering[J]. Geochimica et Cosmochimica Acta,1999,63(9):1277 − 1292. doi: 10.1016/S0016-7037(99)00099-X -