Pub Date : 2022-01-01DOI: 10.2343/geochemj.gj22018
Jixi Zhang, Renxue Shi
7 In this study, the equilibrium isotope fractionation factors between Cd-bearing 8 aqueous solutions and minerals were predicted. The theoretical method used to calculate 9 the Cd isotope fractionation factors is the first-principle quantum chemistry method (Cd: 10 LANL2DZ, other atoms: 6-311+G(d, P)). Reduced partition function ratios (RPFRs) of 11 Cd-bearing minerals (Greenockite and Sphalerite) were modeled by the method of the 12 volume variable cluster model (VVCM). The theoretical method of “water-droplet 13 method” is used to simulate the solvation effect of different Cd-bearing aqueous solutions. 14 The results show that, in most cases, the Cd-bearing aqueous solutions are enriched in 15 114 Cd relative to Greenockite. The Cd isotope fractionation factors between Cd-bearing 16 aqueous solutions and Greenockite are in the range of 0.433- 0.083 (100℃) . And the Cd 17 isotope fractionations between different Cd-bearing species are believed to be widespread. 18 Cd isotope fractionation factors between different reservoirs are of great theoretical 19 significance to many geochemical processes such as surficial geochemical process and 20 ore-forming process. These theoretical parameters are studied systematically and 21 carefully in this study. 22
{"title":"Theoretical Calculation of Equilibrium Cadmium Isotope Fractionation Factors between Cadmium-bearing sulfides and aqueous solutions","authors":"Jixi Zhang, Renxue Shi","doi":"10.2343/geochemj.gj22018","DOIUrl":"https://doi.org/10.2343/geochemj.gj22018","url":null,"abstract":"7 In this study, the equilibrium isotope fractionation factors between Cd-bearing 8 aqueous solutions and minerals were predicted. The theoretical method used to calculate 9 the Cd isotope fractionation factors is the first-principle quantum chemistry method (Cd: 10 LANL2DZ, other atoms: 6-311+G(d, P)). Reduced partition function ratios (RPFRs) of 11 Cd-bearing minerals (Greenockite and Sphalerite) were modeled by the method of the 12 volume variable cluster model (VVCM). The theoretical method of “water-droplet 13 method” is used to simulate the solvation effect of different Cd-bearing aqueous solutions. 14 The results show that, in most cases, the Cd-bearing aqueous solutions are enriched in 15 114 Cd relative to Greenockite. The Cd isotope fractionation factors between Cd-bearing 16 aqueous solutions and Greenockite are in the range of 0.433- 0.083 (100℃) . And the Cd 17 isotope fractionations between different Cd-bearing species are believed to be widespread. 18 Cd isotope fractionation factors between different reservoirs are of great theoretical 19 significance to many geochemical processes such as surficial geochemical process and 20 ore-forming process. These theoretical parameters are studied systematically and 21 carefully in this study. 22","PeriodicalId":12682,"journal":{"name":"Geochemical Journal","volume":"36 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91309021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Kawasaki, Changkun Park, S. Wakaki, Hwayoung Kim, S. Park, T. Yoshimura, K. Nagaishi, Hyun Na Kim, N. Sakamoto, H. Yurimoto
significant variations in (Al/Al)0, implying that thermal processes of condensation and melting for CAI formation occurred contemporaneously and continued for ~0.4 Myr at the very beginning of Solar System formation, under the assumption of homogeneous distributions of 26Al in the forming region (Kawasaki et al., 2020). Among the data available, an example of the smallest analytical errors in (Al/Al)0 for CAIs has been obtained from a fluffy Type A CAI from Vigarano, with (Al/Al)0 = (4.703 ± 0.082) × 10 –5 (Kawasaki et al., 2019); the relative error is 1.7%. (Al/Al)0 for CAIs is determined from the slope of the regression line for CAI mineral data on the Al-Mg evolution diagram (27Al/24Mg vs. radiogenic excess of 26Mg, 26Mg*) for each CAI. 26Mg* values for CAI minerals are accurately determined with SIMS by correcting both natural mass-dependent fractionation and instrumental mass fractionation (IMF) of SIMS for Mg-isotopes (Itoh et al., 2008; Kita et al., 2012; Kawasaki et al., 2017). On the other hand, relative An effect of variations in relative sensitivity factors on Al-Mg systematics of Ca-Al-rich inclusions in meteorites with secondary ion mass spectrometry
(Al/Al)0的显著变化表明，在26Al在形成区域均匀分布的假设下，CAI形成的冷凝和熔化热过程同时发生，并在太阳系形成之初持续了~0.4 Myr (Kawasaki et Al .， 2020)。在现有数据中，从Vigarano公司的蓬松型a型CAI中获得了CAIs (Al/Al)0分析误差最小的示例，(Al/Al)0 =(4.703±0.082)× 10 -5 (Kawasaki et Al .， 2019);相对误差为1.7%。(Al/Al)0由各CAI矿物数据在Al- mg演化图上的回归线斜率确定(27Al/24Mg vs. 26Mg, 26Mg*的放射性过量)。通过校正SIMS对mg同位素的自然质量依赖分选和仪器质量分选(IMF)，可以用SIMS准确测定CAI矿物的mg *值(Itoh等，2008;Kita et al.， 2012;川崎等人，2017)。另一方面，研究了相对敏感因子的变化对二次离子质谱分析富钙铝包裹体Al-Mg分系统的影响
{"title":"An effect of variations in relative sensitivity factors on Al-Mg systematics of Ca-Al-rich inclusions in meteorites with secondary ion mass spectrometry","authors":"N. Kawasaki, Changkun Park, S. Wakaki, Hwayoung Kim, S. Park, T. Yoshimura, K. Nagaishi, Hyun Na Kim, N. Sakamoto, H. Yurimoto","doi":"10.2343/geochemj.2.0634","DOIUrl":"https://doi.org/10.2343/geochemj.2.0634","url":null,"abstract":"significant variations in (Al/Al)0, implying that thermal processes of condensation and melting for CAI formation occurred contemporaneously and continued for ~0.4 Myr at the very beginning of Solar System formation, under the assumption of homogeneous distributions of 26Al in the forming region (Kawasaki et al., 2020). Among the data available, an example of the smallest analytical errors in (Al/Al)0 for CAIs has been obtained from a fluffy Type A CAI from Vigarano, with (Al/Al)0 = (4.703 ± 0.082) × 10 –5 (Kawasaki et al., 2019); the relative error is 1.7%. (Al/Al)0 for CAIs is determined from the slope of the regression line for CAI mineral data on the Al-Mg evolution diagram (27Al/24Mg vs. radiogenic excess of 26Mg, 26Mg*) for each CAI. 26Mg* values for CAI minerals are accurately determined with SIMS by correcting both natural mass-dependent fractionation and instrumental mass fractionation (IMF) of SIMS for Mg-isotopes (Itoh et al., 2008; Kita et al., 2012; Kawasaki et al., 2017). On the other hand, relative An effect of variations in relative sensitivity factors on Al-Mg systematics of Ca-Al-rich inclusions in meteorites with secondary ion mass spectrometry","PeriodicalId":12682,"journal":{"name":"Geochemical Journal","volume":"137 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84827294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A record of 241Am, 236U, 238U, 239Pu, 240Pu, 134Cs and 137Cs in surface seawater and 241Am in aerosols shortly after the FDNPP incident occurred","authors":"","doi":"10.2343/geochemj.2.0615","DOIUrl":"https://doi.org/10.2343/geochemj.2.0615","url":null,"abstract":"","PeriodicalId":12682,"journal":{"name":"Geochemical Journal","volume":"4 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79062098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Takahiro Watanabe, N. Fujita, A. Matsubara, M. Miyake, T. Nishio, C. Ishizaka, Y. Saito-Kokubu
In the case of AMS 14C measurements, the CO2 gas purification procedure from solid samples by the vacuum glass line has been performed as a traditional preparation technique. In some cases (e.g., Morgenroth et al., 2000; Yoneda et al., 2004), sample combustion and gaseous CO2 separation procedures were automatically performed by the EA. Subsequently, the automated graphitization equipment (AGE) was developed by IonPlus AG (Němec et al., 2010; Wacker et al., 2010; Solis et al., 2015). The AGE equipment combined with EA can be utilized as a fully automated sample preparation system to be employed for 14C measurements using standard-sized carbon samples (~1 mg). In fact, currently the third generation of the AGE equipment (AGE3) is commercially available (Solís et al., 2015). Notably, small-mass 14C measurements have been performed on analyte samples characterized by a carbon mass below ~0.1–0.05 mg by the AMS system after manual graphitization using the small-volume vacuum glass line (e.g., Delqué-Količ et al., 2013). However, the EA-AGE3 system has not yet been utilized to perform small-mass sample graphitization for the IAEA standards. In order to evaluate the suitability of the EA-AGE3 system for use in the small-mass graphitization and highefficiency sample preparation techniques, the EA-AGE3 Preliminary report on small-mass graphitization for radiocarbon dating using EA-AGE3 at JAEA-AMS-TONO
在AMS 14C测量的情况下，通过真空玻璃线从固体样品中纯化CO2气体的过程是作为传统的制备技术进行的。在某些情况下(例如，Morgenroth等人，2000;Yoneda et al.， 2004)，样品燃烧和气态CO2分离程序由EA自动执行。随后，自动石墨化设备(AGE)由IonPlus AG开发(nnemec et al.， 2010;Wacker et al.， 2010;Solis et al.， 2015)。与EA相结合的AGE设备可作为全自动样品制备系统，用于使用标准尺寸的碳样品(~ 1mg)进行14C测量。事实上，目前第三代AGE设备(AGE3)已经商业化(Solís et al.， 2015)。值得注意的是，在使用小体积真空玻璃线手工石墨化后，AMS系统对碳质量低于~ 0.1-0.05 mg的分析物样品进行了小质量14C测量(例如，delqu - kolije et al.， 2013)。然而，EA-AGE3系统尚未用于执行IAEA标准的小质量样品石墨化。为了评估EA-AGE3系统在小质量石墨化和高效样品制备技术中的适用性，在JAEA-AMS-TONO上使用EA-AGE3进行小质量石墨化放射性碳定年的初步报告
{"title":"Preliminary report on small-mass graphitization for radiocarbon dating using EA-AGE3 at JAEA-AMS-TONO","authors":"Takahiro Watanabe, N. Fujita, A. Matsubara, M. Miyake, T. Nishio, C. Ishizaka, Y. Saito-Kokubu","doi":"10.2343/geochemj.2.0629","DOIUrl":"https://doi.org/10.2343/geochemj.2.0629","url":null,"abstract":"In the case of AMS 14C measurements, the CO2 gas purification procedure from solid samples by the vacuum glass line has been performed as a traditional preparation technique. In some cases (e.g., Morgenroth et al., 2000; Yoneda et al., 2004), sample combustion and gaseous CO2 separation procedures were automatically performed by the EA. Subsequently, the automated graphitization equipment (AGE) was developed by IonPlus AG (Němec et al., 2010; Wacker et al., 2010; Solis et al., 2015). The AGE equipment combined with EA can be utilized as a fully automated sample preparation system to be employed for 14C measurements using standard-sized carbon samples (~1 mg). In fact, currently the third generation of the AGE equipment (AGE3) is commercially available (Solís et al., 2015). Notably, small-mass 14C measurements have been performed on analyte samples characterized by a carbon mass below ~0.1–0.05 mg by the AMS system after manual graphitization using the small-volume vacuum glass line (e.g., Delqué-Količ et al., 2013). However, the EA-AGE3 system has not yet been utilized to perform small-mass sample graphitization for the IAEA standards. In order to evaluate the suitability of the EA-AGE3 system for use in the small-mass graphitization and highefficiency sample preparation techniques, the EA-AGE3 Preliminary report on small-mass graphitization for radiocarbon dating using EA-AGE3 at JAEA-AMS-TONO","PeriodicalId":12682,"journal":{"name":"Geochemical Journal","volume":"56 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78946947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Z. Ye, Peng-liang Wang, Yike Li, Xin-kui Xiang, Hui Zhang
{"title":"Mineralization in the Shimensi Deposit, Northern Jiangxi Province, China: Evidence from Pb and O isotopes","authors":"Z. Ye, Peng-liang Wang, Yike Li, Xin-kui Xiang, Hui Zhang","doi":"10.2343/geochemj.2.0616","DOIUrl":"https://doi.org/10.2343/geochemj.2.0616","url":null,"abstract":"","PeriodicalId":12682,"journal":{"name":"Geochemical Journal","volume":"51 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79531839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuejing Fang, Jing Yang, Shijin Zhao, Jie Wu, Yuying Huang, Huan Yang
(Andersson et al., 2011; Bush and McInerney, 2015). The interpretation of n-alkane parameters in paleoenvironmental studies has been based primarily on the n-alkane distribution of leaves in modern plants. Besides plant leaves, however, most other plant organs, e.g., flowers and roots, can also produce a large amount of nalkanes. For example, Gamarra and Kahmen (2015) suggested that flowers might contribute an average of 7% nalkanes to grassland soils. In this study, we collected flower and leaf samples from different plant species to compare the distribution and abundance of n-alkane between flowers and leaves. The results would contribute to the limited data set of n-alkanes in modern plants and aid in the interpretation of n-alkane-derived proxies in sediments.
(Andersson et al.， 2011;Bush and McInerney, 2015)。古环境研究中对正构烷烃参数的解释主要基于现代植物叶片的正构烷烃分布。然而，除了植物的叶子，大多数其他植物器官，如花和根，也可以产生大量的烷烃。例如，Gamarra和Kahmen(2015)认为，花可能平均为草地土壤贡献7%的烷烃。在本研究中，我们收集了不同植物物种的花和叶样品，比较了花和叶之间正构烷烃的分布和丰度。该结果将有助于现代植物中有限的正构烷烃数据集，并有助于解释沉积物中正构烷烃衍生的代用品。
{"title":"Shorter average chain length of n-alkanes from flowers than leaves of modern plants: Implications for the use of n-alkane-derived proxies in soils","authors":"Yuejing Fang, Jing Yang, Shijin Zhao, Jie Wu, Yuying Huang, Huan Yang","doi":"10.2343/geochemj.2.0639","DOIUrl":"https://doi.org/10.2343/geochemj.2.0639","url":null,"abstract":"(Andersson et al., 2011; Bush and McInerney, 2015). The interpretation of n-alkane parameters in paleoenvironmental studies has been based primarily on the n-alkane distribution of leaves in modern plants. Besides plant leaves, however, most other plant organs, e.g., flowers and roots, can also produce a large amount of nalkanes. For example, Gamarra and Kahmen (2015) suggested that flowers might contribute an average of 7% nalkanes to grassland soils. In this study, we collected flower and leaf samples from different plant species to compare the distribution and abundance of n-alkane between flowers and leaves. The results would contribute to the limited data set of n-alkanes in modern plants and aid in the interpretation of n-alkane-derived proxies in sediments.","PeriodicalId":12682,"journal":{"name":"Geochemical Journal","volume":"56 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79442377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jumpei Yoshioka, J. Kuroda, N. Takahata, Y. Sano, K. Matsuzaki, H. Hara, G. Auer, S. Chiyonobu, R. Tada
alternation rhythms have been interpreted as reflecting orbital-forced climate changes (Tada, 1991), timescales of the sedimentary cycles have not been precisely constrained. Knowledge of the mechanism controlling the sediment cycles of the Onnagawa Formation is critical to understand the evolution of the Japan Sea basin and its associated changes in the environment during the Middle-to-Late Miocene, when the global climate faced a significant cooling phase (e.g., Holbourn et al., 2013). Chronostratigraphy of the Onnagawa Formation has been developed by diatom biostratigraphy of diatomaceous sediment in the Oga Peninsula (Koizumi et al., 2009). However, many outcrops of the Onnagawa Formation have been suffered from silica diagenesis, which dissolved most diatom frustules composed of opalA and reprecipitated as opal-CT (e.g., Koizumi et al., 2009; Tada and Iijima, 1983). Consequently, preservation of diatom frustules became very poor and diatom biostratigraphy could be barely applicable. Although the Onnagawa Formation in the studied area is suffered from silica diagenesis, it is well exposed, and its continuous sequence can be obtained by splicing several sections. Zircon U-Pb dating of a tuff layer from the Miocene Onnagawa Formation in Northern Japan
交替节律被解释为反映轨道强迫的气候变化(Tada, 1991)，沉积旋回的时间尺度没有得到精确的限制。了解控制Onnagawa组沉积旋回的机制对于理解中新世中晚期全球气候面临显著降温阶段时日本海盆地的演化及其相关环境变化至关重要(例如，Holbourn et al.， 2013)。Oga半岛硅藻沉积的硅藻生物地层学发展了女川组的年代地层学(Koizumi et al.， 2009)。然而，许多Onnagawa组露头受到石英成岩作用的影响，溶解了大部分由opalA组成的硅藻体，再沉淀为opal-CT(例如，Koizumi et al.， 2009;多田和饭岛，1983)。因此，硅藻体的保存变得非常差，硅藻生物地层学几乎不适用。研究区女川组虽然受硅质成岩作用的影响，但其出露程度较好，通过多段拼接可得到其连续层序。日本北部中新世女川组凝灰岩层的锆石U-Pb定年
{"title":"Zircon U-Pb dating of a tuff layer from the Miocene Onnagawa Formation in Northern Japan","authors":"Jumpei Yoshioka, J. Kuroda, N. Takahata, Y. Sano, K. Matsuzaki, H. Hara, G. Auer, S. Chiyonobu, R. Tada","doi":"10.2343/geochemj.2.0622","DOIUrl":"https://doi.org/10.2343/geochemj.2.0622","url":null,"abstract":"alternation rhythms have been interpreted as reflecting orbital-forced climate changes (Tada, 1991), timescales of the sedimentary cycles have not been precisely constrained. Knowledge of the mechanism controlling the sediment cycles of the Onnagawa Formation is critical to understand the evolution of the Japan Sea basin and its associated changes in the environment during the Middle-to-Late Miocene, when the global climate faced a significant cooling phase (e.g., Holbourn et al., 2013). Chronostratigraphy of the Onnagawa Formation has been developed by diatom biostratigraphy of diatomaceous sediment in the Oga Peninsula (Koizumi et al., 2009). However, many outcrops of the Onnagawa Formation have been suffered from silica diagenesis, which dissolved most diatom frustules composed of opalA and reprecipitated as opal-CT (e.g., Koizumi et al., 2009; Tada and Iijima, 1983). Consequently, preservation of diatom frustules became very poor and diatom biostratigraphy could be barely applicable. Although the Onnagawa Formation in the studied area is suffered from silica diagenesis, it is well exposed, and its continuous sequence can be obtained by splicing several sections. Zircon U-Pb dating of a tuff layer from the Miocene Onnagawa Formation in Northern Japan","PeriodicalId":12682,"journal":{"name":"Geochemical Journal","volume":"77 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88173806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Takashi Sambuichi, U. Tsunogai, Kazushige Kura, F. Nakagawa, T. Ohba
have reported 17O-depletion in terrestrial silicates compared with that in hydrospheric H2O such as seawater and meteoric water (Pack et al., 2016; Sharp et al., 2016). The ∆′17O value of mantle-derived silicates ranges from –70 to –30 × 10−6; however, the mean ∆′17O value of meteoric water is +33 × 10−6 and that of seawater collected at various depths is –5 ± 1 × 10−6 (Luz and Barkan, 2010). This difference in ∆′17O between the lithosphere and hydrosphere has been explained by kinetic fractionation of oxygen isotopes during degassing from the magma ocean on the early primitive earth (Tanaka and Nakamura, 2013) or oxygen isotope exchange between the seawater and lithospheric components such as seafloor basalt and continental crust (Pack and Herwartz, 2014; Sengupta et al., 2020; Sengupta and Pack, 2018). The latter explanation has been proposed on the basis of findings that the equilibrium fractionation exponent θ [=ln17α/ln18α; αA-B = RA/ RB where iR corresponds to the abundance ratio of the heavy isotope (iO where i = 17 or 18) to the light isotope (16O).] between silicates and H2O is a funcHigh-precision ∆′17O measurements of geothermal H2O and MORB on the VSMOW-SLAP scale: evidence for active oxygen exchange between the lithosphere and hydrosphere
已经报道了与海水和大气水等水圈H2O相比，陆相硅酸盐的17o损耗(Pack et al.， 2016;Sharp et al.， 2016)。地幔源硅酸盐的∆′17O值为-70 ~ -30 × 10−6;而大气水的平均∆′17O值为+33 × 10−6，不同深度海水的平均∆′17O值为-5±1 × 10−6 (Luz和Barkan, 2010)。早期原始地球岩浆海洋脱气过程中氧同位素的动力学分选(Tanaka and Nakamura, 2013)或海水与海底玄武岩和大陆地壳等岩石圈组分之间的氧同位素交换(Pack and Herwartz, 2014;Sengupta等人，2020;Sengupta和Pack, 2018)。后一种解释是基于平衡分馏指数θ [=ln17α/ln18α;αA-B = RA/ RB，其中iR对应重同位素(iO, i = 17或18)与轻同位素(16O)的丰度比。在VSMOW-SLAP尺度上对地热H2O和MORB的高精度∆′17O测量:岩石圈和水圈之间的活氧交换的证据
{"title":"High-precision Δ′17O measurements of geothermal H2O and MORB on the VSMOW-SLAP scale: evidence for active oxygen exchange between the lithosphere and hydrosphere","authors":"Takashi Sambuichi, U. Tsunogai, Kazushige Kura, F. Nakagawa, T. Ohba","doi":"10.2343/geochemj.2.0644","DOIUrl":"https://doi.org/10.2343/geochemj.2.0644","url":null,"abstract":"have reported 17O-depletion in terrestrial silicates compared with that in hydrospheric H2O such as seawater and meteoric water (Pack et al., 2016; Sharp et al., 2016). The ∆′17O value of mantle-derived silicates ranges from –70 to –30 × 10−6; however, the mean ∆′17O value of meteoric water is +33 × 10−6 and that of seawater collected at various depths is –5 ± 1 × 10−6 (Luz and Barkan, 2010). This difference in ∆′17O between the lithosphere and hydrosphere has been explained by kinetic fractionation of oxygen isotopes during degassing from the magma ocean on the early primitive earth (Tanaka and Nakamura, 2013) or oxygen isotope exchange between the seawater and lithospheric components such as seafloor basalt and continental crust (Pack and Herwartz, 2014; Sengupta et al., 2020; Sengupta and Pack, 2018). The latter explanation has been proposed on the basis of findings that the equilibrium fractionation exponent θ [=ln17α/ln18α; αA-B = RA/ RB where iR corresponds to the abundance ratio of the heavy isotope (iO where i = 17 or 18) to the light isotope (16O).] between silicates and H2O is a funcHigh-precision ∆′17O measurements of geothermal H2O and MORB on the VSMOW-SLAP scale: evidence for active oxygen exchange between the lithosphere and hydrosphere","PeriodicalId":12682,"journal":{"name":"Geochemical Journal","volume":"20 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90492790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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