Article
Geochemistry & Geophysics
Martin Yan Hei Li, Fang-Zhen Teng, Mei-Fu Zhou
Summary: Continental weathering plays a crucial role in releasing magnesium from rocks to the hydrosphere and biosphere. Magnesium isotopes can be used as a powerful tool to trace the biogeochemical cycle of magnesium, but the causes of significant isotopic fractionation during silicate weathering are not well understood. This study demonstrates that the dissolution and formation of phyllosilicates are the main factors controlling magnesium isotopic fractionation during sub-tropical weathering of granite, and different mechanisms of formation and dissolution could cause variations in fractionation.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geochemistry & Geophysics
Xin-Yuan Zheng, Brian L. Beard, Mason Neuman, Maria F. Fahnestock, Julia G. Bryce, Clark M. Johnson
Summary: Recent discoveries have shown significant variations in stable K isotope ratios among different terrestrial samples, suggesting that K isotopes can be used as a new tracer for the global K cycle. The observation of seawater 841K being 0.6%o higher than the bulk silicate Earth remains unexplained. The role of hydrothermal systems in the ocean, which are both a major K source and sink, is critical to understanding this puzzle. The study found that fluid 841K values in mid-ocean ridge hydrothermal fluids are influenced by water-rock interactions and show small but significant isotope fractionation. These results suggest that MOR hydrothermal systems are not responsible for the heavy 841K value of seawater. The study also highlights the importance of marine sedimentary sinks, such as authigenic clay formation, in the global K cycle. Additionally, applying the findings to published data from ophiolites suggests the possibility of significantly lower seawater 841K values during the Ordovician.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Utpalendu Haldar, Ramananda Chakrabarti, Roberta L. Rudnick
Summary: In this study, calcium stable isotopes were analyzed in well-characterized saprolite samples near Cayce, South Carolina to understand the isotopic fractionation during chemical weathering. The results showed that the δCa-44/40 values of the saprolites varied significantly and were generally higher than the unweathered metadiabase, indicating the loss of light Ca isotopes during weathering. The correlation between the δCa-44/40 values and other parameters suggests that the formation of clay minerals and the progressive loss of Ca are controlling factors for the Ca stable isotopic variability in the saprolites.
Article
Geochemistry & Geophysics
Jong-Sik Ryu, Nathalie Vigier, Louis Derry, Oliver A. Chadwick
Summary: An analysis of soil samples of varying age and depth from the Hawaiian Islands revealed complex fractionation of magnesium and its isotopes during weathering and soil development, with variations influenced by plant recycling and mineral transformations as time progresses.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geochemistry & Geophysics
Joseph A. Graly, Kathy J. Licht, Nicole A. Bader, Christine M. Kassab, David L. Bish, Michael R. Kaplan
Summary: The study analyzes the chemical and mineralogical transformations in Mt Achernar Moraine, finding that salts and carbonate minerals increase with exposure age while clay minerals and amorphous cements break down in smaller proportions. The formation of most minerals is attributed to atmospheric acids reacting with other minerals, and these reactions occur in both subglacial and surface environments.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Geochemistry & Geophysics
Claire J. Nelson, Andrew D. Jacobson, Tobias B. Weisenberger
Summary: This study examines the Ca isotope geochemistry of Icelandic rivers and aims to improve the delta Ca-44/40 tracer, identify solute sources, and investigate the role of basalt weathering in regulating Earth's climate. The results show that groundwater and hydrothermal water inputs play a significant role in the calcium content of Icelandic rivers.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Geosciences, Multidisciplinary
Haowei Mei, Xing Jian, Wei Zhang, Hanjing Fu, Shuo Zhang
Summary: Continental weathering is essential in connecting Earth's spheres, shaping landscapes, and regulating chemical cycles and global climate. A study in southeast China on granitic regolith profiles reveals intensive chemical weathering in top-soil samples, with depletion of plagioclase and K-feldspar and formation of kaolinite. The underlying oxidized-soil samples show higher chemical index of alteration values and enrichment of certain elements, indicating the importance of petrographic and mineralogical proxies in evaluating weathering intensity for regolith profiles.
Article
Geochemistry & Geophysics
Wenrong Cao, Clement P. Bataille, Ethan R. Leuchter, Xiqiang Zhou
Summary: Continental arcs influence the global carbon cycle through degassing and chemical weathering. The isotopic variations of continental arcs on a global scale are mainly controlled by geological or tectonic drivers. During the mid-Cretaceous, most continental arcs were built on isotopically-juvenile basements and yielded juvenile isotopes globally.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Chemistry, Physical
I. Campana, J. G. Wynn, J. Iglesias-Cibanal, A. Benito-Calvo, A. Alvaro-Gallo, L. Bermejo, A. Perez-Gonzalez, J. M. Bermudez de Castro
Summary: The isotopic composition of water used in pre-treatment solutions has an influence on the isotopic composition of clay minerals. While HCl pre-treatment significantly alters the clay minerals, H2O2 pre-treatment has negligible effects. The variability in the alteration mainly depends on clay mineralogy, especially the quantity of smectite.
APPLIED CLAY SCIENCE
(2022)
Article
Geosciences, Multidisciplinary
B. Ye, J. R. Michalski
Summary: Compositional stratigraphy on Mars often shows Al-rich clay minerals overlaying Fe/Mg-rich clay minerals, with some occurrences in settings where the protoliths are likely pyroclastic materials. The presence of clay-bearing deposits in volcanic areas suggests precipitation-driven weathering of ash deposits. The early sedimentary record of Mars may have been dominated by pyroclastic deposits, linking clay minerals to elements of Mars' climate, weathering, and sedimentary processes.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geochemistry & Geophysics
Philip A. E. Pogge von Strandmann, Lara R. Cosford, Chun-Yao Liu, Xianyi Liu, Alexander J. Krause, David J. Wilson, Xiaoqing He, Alex J. McCoy-West, Sigurour R. Gislason, Kevin W. Burton
Summary: This study investigates the impact of riverine discharge and weathering intensity on lithium isotopes in a mono-lithological terrain using Icelandic rivers as the case study. The results show that water-rock interaction time is a primary control on the fractionation of Li isotopes. The relationship between weathering intensity and delta 7Li is observed in these basaltic rivers, but with different values compared to global rivers due to lithological control. The study also highlights the varying fractionation between the clay fraction and the dissolved load with both W/D and discharge. Overall, this study confirms the utility of Li isotopes as a tracer of weathering processes and provides important insights for interpreting detrital delta 7Li values.
Article
Geochemistry & Geophysics
Valens Hishamunda, Ramananda Chakrabarti, Sambuddha Misra, Alexandra V. Turchyn
Summary: This study investigates the calcium isotopic compositions of the Godavari River in India and finds that the delta 44/40Ca values of river water samples vary significantly depending on the season and location, influenced by basalt weathering and groundwater discharge. Additionally, carbonate precipitation in the river affects the delta 44/40Ca values. A comparison with basalt-draining rivers in Iceland reveals distinct differences in geochemical and calcium isotopic compositions, suggesting fundamental differences in weathering processes in different climatic regions.
Article
Soil Science
M. Bonnet, L. Caner, M. Siitari-Kauppi, A. Mazurier, A. S. Mexias, N. Dani, P. Sardini
Summary: This study investigated the mineralogical transformations and the increase in total porosity during granodiorite weathering in South Brazil by combining petrographical observations, mineralogical analyses, and porosity measurements. The results show that the increase in total porosity is likely controlled by the opening of the porosity.
Article
Geochemistry & Geophysics
Christopher A. Parendo, Stein B. Jacobsen, Terry Plank
Summary: Characterizing the K-isotope compositions of marine sediments is crucial for studying K cycling in the ocean system and subduction zones. The study reveals subtle variations in K-isotope compositions in deep-sea sediments in the western Pacific, influenced by mixing of volcanic ash and terrigenous materials.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Geochemistry & Geophysics
Xiaoqiang Li, Guilin Han, Man Liu, Jinke Liu, Qian Zhang, Rui Qu
Summary: This study systematically investigated the K contents and stable K isotopic compositions of various water and sediment samples in the Upper Mun Rive catchment, northeast Thailand. The results show that K isotopes can serve as an ideal indicator to constrain silicate weathering processes and anthropogenic inputs at the catchment scale.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Geosciences, Multidisciplinary
Huan Cui, Alan J. Kaufman, Shuhai Xiao, Chuanming Zhou, Maoyan Zhu, Mengchun Cao, Sean Loyd, Peter Crockford, Xiao-Ming Liu, Steven Goderis, Wei Wang, Chengguo Guan
Summary: The presence of sulfate minerals during the Ediacaran Shuram excursion suggests an increase in seawater sulfate concentrations and potential facilitation of sulfate mineral diagenesis. This may have also led to increased barite deposition in shelf environments. The dynamic interplay of biogeochemical cycles in response to the Shuram oxygenation event highlights the complex processes involved in Earth's history.
JOURNAL OF THE GEOLOGICAL SOCIETY
(2022)
Article
Geochemistry & Geophysics
Mason Neuman, Astrid Holzheid, Katharina Lodders, Bruce Fegley, Bradley L. Jolliff, Piers Koefoed, Heng Chen, Kun Wang
Summary: The study conducted twenty heating experiments to investigate the behavior of K, Cu, and Zn evaporation and isotopic fractionation from basaltic melts at high temperatures. Results show that Zn is the most volatile element followed by Cu and K. However, partitioning of Zn into spinel layers affects the Zn isotope fractionation factor. Higher temperatures and lower oxygen fugacities promote evaporation, and the experimentally determined fractionation factors for K and Cu are significantly larger than the apparent observed fractionation factors from lunar basalts.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Geochemistry & Geophysics
Wenshuai Li, Xiao-Ming Liu, Kun Wang, Yongfeng Hu, Atsushi Suzuki, Toshihiro Yoshimura
Summary: Potassium participates in coral biological activities and its isotope fractionation is important for interpreting coral records. This study evaluates the distribution and variation of potassium isotopes in the skeleton of corals and identifies the influence of biotic and abiotic controls on potassium partitioning and isotope fractionation. The findings highlight the role of physiological modulation in the phase distribution of potassium in coral skeletons and its isotopic variation.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Xiao-Feng Liu, Shikui Zhai, Xi-Kai Wang, Xinyu Liu, Xiao-Ming Liu
Summary: Marine carbonates, formed through sedimentation and diagenetic processes, can preserve primary seawater REY geochemical characteristics even after experiencing variable diagenetic alteration. This study investigates the REY geochemical features of reefal carbonates from the Xisha Islands and finds that the original seawater REY signatures are retained regardless of changes in mineralogical composition, diagenetic fluid composition, and redox state.
Article
Ecology
Yi-Wen Cao, Xiao-Ming Liu, Chao Wang, Edith Bai, Nanping Wu
Summary: This study characterized the rare earth element (REE) contents in different fractions of soils and investigated their relationships with climatic factors across a large-scale northern China transect. The results showed that the REE concentrations were correlated with climate factors, and the REE distribution patterns were consistent with the upper continental crust composition.
ECOLOGICAL PROCESSES
(2022)
Article
Geology
Heran Huang, Yudong Liu, Yibo Yang, Rongsheng Yang, Chengcheng Ye, Erwin Appel, Xiaomin Fang, Xiaoming Liu
Summary: The relationship between tectonic uplift, climate change, and continental silicate weathering is complex and has been the subject of debate. This study investigates this relationship in the tectonically active northeast Tibet region by analyzing long-term climatic and silicate weathering records. The study finds distinct correlations between silicate weathering and regional climate on both long-term and short-term time scales. The long-term consistency is attributed to aridification in inland Asia, while the short-term inconsistencies are influenced by changes in the sediment routing system impacted by regional climate within a tectonically active setting.
SEDIMENTARY GEOLOGY
(2022)
Article
Geochemistry & Geophysics
Wenshuai Li, Xiao-Ming Liu, Yan Hu, Fang-Zhen Teng, Oliver A. Chadwick
Summary: The controls on potassium (K) isotope fractionation during chemical weathering are evaluated using two regolith profiles developed over -350 kyr on the humid and arid sides of Kohala Mountain, Hawai'i. The findings suggest that potassium enrichment and loss occur in both regolith profiles, with the humid profile showing significant potassium enrichment in shallow horizons and loss in deeper horizons. The presence of K-bearing mineral aerosols in the humid regolith may explain the apparent contradiction between enrichment and loss. Climate, weathering, plant cycling, and the addition of marine and mineral aerosols all contribute to the potassium isotope composition in Hawaiian regoliths.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Geochemistry & Geophysics
Wenshuai Li, Xiao-Ming Liu, Kun Wang, Yoshio Takahashi, Yongfeng Hu, Oliver A. Chadwick
Summary: We conducted a study to interpret the fate of potassium (K) during forest soil development in Hawai'i. We used spectroscopic and geochemical approaches and found that potassium derived from weathering of lava dominates in the early stages of soil formation, but its contribution declines over time. The isotopic composition of soil potassium reflects different processes, including chemical weathering, plant cycling, and atmospheric inputs.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Geosciences, Multidisciplinary
Cheng Cao, Clement P. Bataille, Haijun Song, Matthew R. Saltzman, Kate Tierney Cramer, Huaichun Wu, Christoph Korte, Zhaofeng Zhang, Xiao-Ming Liu
Summary: In the Precambrian, reverse weathering played a key role in the carbon cycle, but marine silicifiers reduced its importance in the Phanerozoic. This study shows that an increase in reverse weathering rates led to a decline in seawater Li isotopes during the Late Permian and Early Triassic, explaining the failure of chemical weathering to decrease atmospheric CO2 levels during this period.
Article
Geosciences, Multidisciplinary
Cheng Cao, Xiao-Ming Liu, Jun Chen
Summary: Reconstructing redox conditions in the paleo-ocean is crucial for understanding the Earth's biogeochemical evolution. This study provides thermodynamics-based models that link cerium anomaly to dissolved oxygen, pH, and phosphate concentration in the ocean. The cerium anomaly is insensitive to dissolved oxygen changes in oxic environments but well correlated in anoxic environments. This research has significant implications for quantifying dissolved oxygen levels using lanthanide patterns in ancient marine carbonates, particularly during anoxic events in the paleo-ocean.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Environmental Sciences
Wenshuai Li, Xiao-Ming Liu
Summary: This study investigates the patterns and processes of Li isotope fractionation during adsorption on kaolinite and smectite, and finds that fluid chemistry can affect the degree of clay Li adsorption but has negligible impacts on isotope fractionation.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Geochemistry & Geophysics
Zhen Wang, Robert Hill, Gordon Williams, Gary S. Dwyer, Jun Hu, Ewald Schnug, Roland Bol, Yajie Sun, Drew S. Coleman, Xiao-Ming Liu, Michael R. Sandstrom, Avner Vengosh
Summary: Phosphate rock contains important geological and environmental information. This study analyzes the lead isotopic compositions and trace element concentrations of global sedimentary and igneous phosphate rocks to evaluate their geological origin and potential for environmental tracing. The results show that sedimentary phosphate rocks have more radiogenic lead isotopes than igneous rocks, indicating different depositional environments. The lead isotopes and trace element proxies can be used to trace contamination from phosphate rock mining and fertilizer application. Overall, this study provides new data on the geochemistry of phosphate rocks and fertilizers, with implications for both geological and environmental research.
Article
Geochemistry & Geophysics
Stephen J. Turner, Mattison H. Barickman, Julian Rodriguez, David A. Fike, Clive M. Jones, Kun Wang, Ivan P. Savov, Samuele Agostini, Michael J. Krawczynski, Rita Parai
Summary: The geochemistry of arc magmas provides insight into the chemical outfluxes from subducting slabs. Boron (B) abundances and isotope ratios act as tracers of slab-derived components, with new measurements in Nicaraguan volcanic centers indicating a B-rich slab component primarily sourced from subducted altered oceanic crust (AOC) and minor input from subducted sediments. This finding suggests that the volatile element budget delivered to the volcanic arc is mostly derived from the ocean crust and that volatiles may be recycled into the deeper mantle beneath Central America.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geochemistry & Geophysics
Kun Wang, Dmitri A. Ionov
Summary: Subduction plays a major role in recycling water, volatiles, and incompatible elements into Earth's mantle, and the isotopic signatures of potassium (K) can be used as a new tracer in subduction events. A study on mantle harzburgite xenoliths from Avacha volcano in Kamchatka, Russia, shows that slab-derived fluids infiltrated the sub-arc mantle and can significantly fractionate K isotopes. This provides direct evidence for the impact of subduction dehydration and fluid percolation on K isotopes in the mantle lithosphere.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geochemistry & Geophysics
Wenshuai Li, Ryoichi Nakada, Yoshio Takahashi, Richard M. Gaschnig, Yongfeng Hu, Mohsen Shakouri, Roberta L. Rudnick, Xiao-Ming Liu
Summary: This study investigates the secular change in the geochemical composition of cerium in the upper continental crust (UCC) for tracing oxidative weathering. The results show that there are no distinguishable secular changes in the cerium anomaly and stable isotope composition of the average UCC. The study emphasizes the importance of utilizing the valence state of cerium as a reliable indicator of redox conditions.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Geochemistry & Geophysics
Lingyu Zhang, Kristoffer Szilas
Summary: This study presents new petrological and geochemical data for the Narssaq Ultramafic Body (NUB) in the Itsaq Gneiss Complex of SW Greenland. The results indicate that the ultramafic rocks of NUB are not mantle residues, but instead represent crustal cumulates derived from high-Mg magmas.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Rong Xu, Sarah Lambart, Oliver Nebel, Ming Li, Zhongjie Bai, Junbo Zhang, Ganglan Zhang, Jianfeng Gao, Hong Zhong, Yongsheng Liu
Summary: This study investigated the iron isotope compositions of Cenozoic basalts in Southeast China, finding significant variations related to different types of basalts and their respective sources.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
C. J. Ebinger, Miriam C. Reiss, Ian Bastow, Mary M. Karanja
Summary: The East African rift system is formed above mantle upwellings and the formation of rifts is related to lithospheric thinning and magmatic activity. The amount of splitting varies spatially and the fast axes are predominantly parallel to the orientation of the rifts. Thick lithospheric modules have less splitting and different orientations, which may indicate mantle plume flow. Splitting rotates and increases in strength as it enters the rift zones, suggesting that the anisotropy is mainly present at shallow depths.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Correction
Geochemistry & Geophysics
Ekaterina Rojas-Kolomiets, Owen Jensen, Michael Bizimis, Gene Yogodzinski, Lukas Ackerman
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Robert W. Nicklas, Igor S. Puchtel, Ethan F. Baxter
Summary: Oxygen fugacity is a fundamental parameter for understanding redox processes in igneous systems. This study compares the Fe-XANES oxybarometry method with the V-in-olivine method for evaluating fO(2) in MORB lavas. The results show that the V-in-olivine method is not applicable to samples with low MgO content, and that the majority of Archean komatiite sources have lower fO(2) than modern MORB.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Chunfei Chen, Stephen F. Foley, Sebastian Tappe, Huange Ren, Lanping Feng, Yongsheng Liu
Summary: The volatile components CO2 and H2O play a major role in mantle melting and heterogeneity. In this study, Ca isotopes were used to trace the lithological heterogeneity in alkaline magmatic rocks. The results revealed the presence of K-richterite and carbonate components as the source of alkaline magmas with low delta 44/40Ca values. These findings highlight the importance of Ca isotopes as a robust tracer of lithological variation caused by volatiles in the Earth's upper mantle.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Timothee Jautzy, Gilles Rixhon, Regis Braucher, Romain Delunel, Pierre G. Valla, Laurent Schmitt, Aster Team
Summary: Although the current approach to estimate catchment-wide denudation rates using only 10Be concentrations has made significant progress in geomorphology, this study argues for the inclusion of 26Al measurements and testing of steady-state assumptions in slow eroding, formerly glaciated landscapes. The study conducted measurements of both 10Be and 26Al in stream sediments from the Vosges Massif in France and found that elevation, slope, channel steepness, and precipitation were the primary factors controlling denudation rates. The study also revealed a significant relationship between the extent of past glaciation and the cosmogenic (un-)steadiness in the stream sediments.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Erik van der Wiel, Douwe J. J. van Hinsbergen, Cedric Thieulot, Wim Spakman
Summary: Numerical models of Earth's mantle dynamics can predict the vigour and mixing of mantle flow, and the average slab sinking rates are an unexplored parameter that can provide intrinsic information on these characteristics. Through numerical experiments, it has been found that slab sinking rates are strongly correlated with mantle convection and mixing, and may explain geochemical observations from hotspot volcanoes.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)