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Trace element (Be, Zn, Ga, Rb, Nb, Cs, Ta, W) partitioning between mica and Li-rich granitic melt: Experimental approach and implications for W mineralization Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-05-10 Xu Gao, Julie Anne-Sophie Michaud, Zhenhua Zhou, Ingo Horn, Renat R. Almeev, Stefan Weyer, François Holtz
Mica is the most important carrier of rare alkalis (Li, Rb and Cs) and volatiles, and also a major host of rare metals such as Sn, W, Nb and Ta. Thus, the knowledge of trace element partitioning between mica and silicate melt is crucial to understand enrichment mechanisms of ore metals in evolved silicic systems. However, experimental data are scarce, mainly because the synthesis of large mica grains
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Reaction calorimetry and structural crystal properties of non-ideal binary rhabdophane solid solutions (Ce1−xREExPO4·nH2O) Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-05-06 Alexander P. Gysi, Nicole C. Hurtig, Hannah Juan Han, Emma C. Kindall, Xiaofeng Guo, Dmitrii A. Kulik, George Dan Miron
Rhabdophane is a hydrous phosphate that commonly replaces monazite as a weathering product in critical mineral deposits during the alteration of rare earth elements (REE) bearing carbonatites and alkaline igneous complexes. It is an important host to the light (L)REE (i.e., La to Gd) but the stability and structure of binary solid solutions between the Ce and the other LREE endmembers have not yet
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Towards a better understanding of the geochemical proxy record of complex carbonate archives Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-05-01 M. Mueller, B.F. Walter, R.J. Giebel, A. Beranoaguirre, P.K. Swart, C. Lu, S. Riechelmann, A. Immenhauser
Carbonate archives record a brief snapshot of the ambient Earth’s surface conditions at their deposition. However, the geologically reasonable extraction and interpretation of geochemical proxy data from ancient, diagenetically altered rock archives is fraught with problems. Three issues stand out: the dichotomy between petrographic and geochemical alteration; the lack of quantitative age constraints
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Sampling Earth’s mantle at intra-transform spreading ridges Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-05-01 Camilla Sani, Alessio Sanfilippo, Sergey Skolotnev, Marco Ligi, Felix Genske, Andreas Stracke
The Doldrums transform system, located in the Equatorial Atlantic at 7–8°N, is a 110 km-wide multi-fault shear zone, with five active transform faults separated by four short intra-transform ridge segments (ITRs). The two central ITRs, ITR-2 and ITR-3, are significantly deeper than the peripheral ridge segments, suggesting differences in the thermal conditions of the sub-ridge mantle. New chemical
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Ancient melt percolation in forearc mantle pyroxenites: Evidence from highly siderophile elements and Os isotope ratios Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-05-01 Yang Xu, Chuan-Zhou Liu, Xuefa Shi
Pyroxenites, comprising only approximately 2 %–10 % by volume of the upper mantle, are among the most important lithological heterogeneity in the mantle. The formation of pyroxenite veins within peridotites is often attributed to migrating melts which provides an important mechanism for crust-mantle interaction. The Re–Os isotope system provides valuable insight into crust-mantle interaction, as there
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Changes in litter and nitrogen deposition differentially alter forest soil organic matter biogeochemistry Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-05-01 Isla Wrightson, Maryam Tabatabaei Anaraki, John Den Uyl, Knute J. Nadelhoffer, Kate Lajtha, Myrna J. Simpson
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Dislocation-mediated interfacial re-equilibration of pyrite: An alternative model to interface-coupled dissolution-reprecipitation and gold remobilisation Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-27 Denis Fougerouse, Steven M. Reddy, Sumail, Joël Brugger, Nicolas Thébaud, William D.A. Rickard, Lin Yang, Zakaria Quadir, Malcolm P. Roberts, Andrew G. Tomkins, Laure Martin, Laura Petrella, Christopher R. Voisey
Minerals and/or their compositions (substituted minor elements) can become metastable in changing conditions or if formed outside of equilibrium. Unstable minerals undergo chemical and/or structural modifications at rates determined by re-equilibration processes, such as diffusion, coupled dissolution-reprecipitation and recrystallization. However, re-equilibrated domains with sharp contacts that lack
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Boron in wildfires: New insights into boron isotope fractionation during volatilisation, leaching and adsorption after combustion Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-24 Shawn Lu, Anthony Dosseto, Damien Lemarchand
Wildfires are hazards of increasing significance in recent decades. Our ability to forecast the evolution of fire regimes is inhibited by the lack of records of key fire parameters such as fire severity. Boron isotopes in the soil clay fraction have been shown to vary with fire severity, where increased B coincides with higher fire severity. To elucidate the relationship between the B isotope composition
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Discovery of abundant shock-induced metallic lead nanograins in lunar zirconolite Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-21 Ai-Cheng Zhang, Hao-Xuan Sun, Tian-Ran Trina Du, Jia-Ni Chen, Li-Xin Gu
The behaviors of radiogenic Pb in Zr-minerals are critical for reconstructing the chronological framework for the evolutionary history of our Earth and other planetary bodies. Previous investigations have revealed the presence of Pb nanograins in some terrestrial zircons and attributed it to radiation decay of U and mobilization and accumulation in zircon and a subsequent thermal metamorphic event
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A spectroscopic study of the stability of uranyl-carbonate complexes at 25–150 °C and re-visiting the data available for uranyl-chloride, uranyl-sulfate, and uranyl-hydroxide species Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-20 A. Migdisov, E. Bastrakov, C. Alcorn, M. Reece, H. Boukhalfa, F.A. Capporuscio, C. Jove-Colon
The stabilities of uranyl-carbonate and uranyl-hydroxide aqueous complexes were experimentally determined at temperatures ranging from 25 to 125 °C using in situ UV–vis and Raman spectroscopic techniques. Combined with earlier determinations of the stability of chloride, sulfate, and hydroxide complexes at temperatures up to 250 °C, these data permit to create a consolidated dataset suitable for modeling
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Insights on the origin of oldhamite in enstatite meteorites from Ca stable isotopes Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-20 Wei Dai, Frederic Moynier, Julien Siebert
In order to understand the origin of oldhamite (CaS) in enstatite meteorites, we report Ca isotopic compositions (Ca) of oldhamite (obtained from water leachate of bulk chondrites and aubrites and mineral separates from the Norton County aubrite) and silicate minerals from different types of enstatite chondrites and aubrite. The Ca of the bulk enstatite chondrites range from 1.05 ‰ to 1.24 ‰, with
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An experimental simulation of oxygen isotope exchange reaction between amorphous silicate dust and carbon monoxide gas in the early Solar System Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-18 Daiki Yamamoto, Noriyuki Kawasaki, Shogo Tachibana, Lily Ishizaki, Ryosuke Sakurai, Hisayoshi Yurimoto
The reaction mechanism and kinetics of oxygen isotope exchange between tens of nanometer-sized amorphous silicate grains with forsterite composition (amorphous forsterite) and low-pressure carbon monoxide (CO) gas () of 0.05–1 Pa at 643–883 K were examined to investigate oxygen isotopic evolution in the protosolar disk that led to the mass-independent oxygen isotopic variation of planetary materials
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Densely populated biofilms and linked iron and sulfur cycles in the fractured-rock continental subsurface Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-16 Christopher J. Schuler, Amanda Patsis, Scott C. Alexander, David Hsu, William S. Dowd, Woonghee Lee, Sarick L. Matzen, Matthew A. Marcus, Cody S. Sheik, Jill M. McDermott, Peter K. Kang, Cara M. Santelli, Brandy M. Toner
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Tidally driven porewater exchange and diel cycles control CO2 fluxes in mangroves on local and global scales Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-16 Alex Cabral, Yvonne Y.Y. Yau, Gloria M.S. Reithmaier, Luiz C. Cotovicz Jr., João Barreira, Göran Broström, Bárbara Viana, Alessandra L. Fonseca, Isaac R. Santos
Mangrove soils are highly enriched in organic carbon. Tidal pumping drives seawater and oxygen into mangrove soils during flood tide and releases carbon-rich porewater during ebb tides. Here, we resolve semi-diurnal (flood/ebb tides), diel (day/night) and weekly (neap/spring tides) drivers of porewater-derived CO fluxes in two mangroves and update global estimates of CO emissions building on earlier
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Constraints on lunar regolith resurfacing from coupled modeling of stochastic gardening and neutron capture effects Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-16 Justin Y. Hu, Ingo Leya, Nicolas Dauphas, Auriol S.P. Rae, Helen M. Williams
The regolith evolution of airless bodies, like the Moon, is primarily controlled by impact cratering. Since the Apollo Era, measurements of cosmic ray exposure (CRE)-induced Sm and Gd isotopes in lunar drill cores have provided insights into the secondary neutron spectra in the lunar regolith. Since the production and transport of secondary neutrons vary with the regolith’s chemical composition and
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Trends in estuarine pyrite formation point to an alternative model for Paleozoic pyrite burial Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-16 Kalev Hantsoo, Maya Gomes, Dana Brenner, Jeffrey Cornwell, Cindy M. Palinkas, Sairah Malkin
The early Paleozoic Era (∼540–420 Ma) was an interval of profound biogeochemical changes including increasing oxygen (O) and the onset of bioturbation (sediment mixing by animals). It is hypothesized that incipient bioturbation caused a monotonic decrease in sedimentary burial of pyrite (FeS), which would have slowed atmospheric O accumulation. However, pyrite accumulation can exhibit complex responses
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Experimental constraints on formation of silica-rich igneous rims around chondrules in CR chondrites Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-15 Aimee Smith, Rhian H. Jones
Silica-rich igneous rims (SIRs) occur commonly as an outer rim layer on porphyritic chondrules in CR (Renazzo-like) chondrites, as well as more rarely in other chondrite groups. Formation conditions for SIRs can provide insight into chemical and physical conditions in the chondrule-forming region of the protoplanetary disk, as well as helping to understand temporal changes to successive thermal events
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Towards a new impact geochronometer: Deformation microstructures and U-Pb systematics of shocked xenotime Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-15 Cilva Joseph, Denis Fougerouse, Aaron J. Cavosie, Hugo K.H. Olierook, Steven M. Reddy, Tommaso Tacchetto, Raiza R. Quintero, Allen Kennedy, David W. Saxey, William D.A. Rickard
Shock-deformation microstructures in xenotime have been proposed to record diagnostic evidence for meteorite impacts. Evaluating the potential for impact-induced U-Pb age resetting of the various microstructures that form in shocked xenotime remains largely unexplored. In this study, we investigate the U-Pb systematics of shocked xenotime from three impact structures, including Vredefort (South Africa)
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Reduction and transformation of Cr(VI)-associated ferrihydrite by Shewanella oneidensis MR-1: Kinetics and secondary minerals Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-14 Shiwen Hu, Qi Wang, Hanyue Zhang, Yang Yang, Guojun Chen, Shan Wang, Chongxuan Liu, Tongxu Liu
Hexavalent chromium (Cr(VI)) could be sequestrated by soils via microbial reduction to Cr(III) and association with minerals, however, quantitative understanding of metal reducing bacteria on the coupled kinetics of Cr and Fe minerals is still lacking. Here, microbial-mediated ferrihydrite transformation and reductive sequestration of Cr(VI) were investigated with MR-1 under varying Cr/Fe ratios. Quantitative
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Oxygen isotope study of the Asuka-881020 CH chondrite II: Porphyritic chondrules Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-10 Daisuke Nakashima, Takaaki Noguchi, Takayuki Ushikubo, Makoto Kimura, Noriko Kita
Oxygen isotope ratios and elemental compositions of porphyritic chondrules and olivine and pyroxene fragments in the Asuka-881020 CH chondrite were analyzed. The oxygen isotope ratios inside individual porphyritic chondrules are homogeneous within the uncertainty, except for relict grains of olivine and low-Ca pyroxene that have distinct oxygen isotope ratios. The average oxygen isotope ratios of the
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Surface properties of schwertmannite with different sulfate contents and its effect on Cr(VI) adsorption Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-09 Chaoping Wang, Kai Chen, Meiling Yin, Yuting Zhou, Qinglin Zhuang, Qianqian Cao, Zhi Dang, Chuling Guo
Sulfate is a critical component of schwertmannite. However, the sulfate content of schwertmannite decreases with the increase in AMD-polluted river pH value, and its impact on the surface properties and Cr(VI) adsorption of schwertmannite remains unclear. To address this issue, different methods, including batch adsorption, N physisorption, scanning electron microscopy (SEM), potentiometric titration
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Effects of particle size and AQDS on the flow of electron equivalents between magnetite and aqueous Fe2+ Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-08 Huan Peng, Zhenli Zhu, Carolyn I. Pearce, Anxu Sheng, Mingjun Nie, Alpha T. N'Diaye, Xin Zhang, Kevin M. Rosso, Juan Liu
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Tracing material transport during subduction inception: Insights from potassium isotopes in the crustal sequence of the Troodos ophiolite Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-08 Qi-Qi Pan, Yan Xiao, Ben-Xun Su, Paul T. Robinson, Wen-Jun Li, Jing Wang, Xia Liu
Potassium (K) isotopic compositions for a suite of crustal rocks (plutonic unit, sheeted dike complex, and volcanic sequence) in the Troodos ophiolite, Cyprus, were determined to investigate fluid-transport processes during subduction inception. The gabbros and plagiogranites in the plutonic unit have restricted K isotopic compositions (0.01–0.20 ‰ and −0.17 to 0.02 ‰, respectively), whereas diabases
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Reliability of micritic carbonates in recording well-preserved isotopic composition and implications for paleoelevation estimates in central Tibet Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-07 Lin Li, Jay Quade, Carmala Garzione, William F. Defliese, Peter DeCelles, Paul Kapp
Paleoelevation and paleoclimate reconstructions based on carbonate proxies rely on the preservation of syndepositional surface water isotopic signatures. This study investigates the reliability of fine-grained carbonates (micrites) in recording well-preserved isotopic composition. Utilizing a suite of research tools, including petrography, X-ray diffraction mineralogy, stable isotopes, clumped isotope
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Aluminium substitution affects jarosite transformation to iron oxyhydroxides in the presence of aqueous Fe(II) Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-07 Andrew R.C. Grigg, Luiza Notini, Ralf Kaegi, Laurel K. ThomasArrigo, Ruben Kretzschmar
Jarosite is an abundant mineral in acidic environments, often found in acid sulfate soil (ASS) and acid-mine drainage (AMD). As a store of Fe, K, S and acidity, and a scavenger for major and trace elements, jarosite plays an important role in the biogeochemistry of acid sulfate environments. When ASS and AMD become anoxic, reducing conditions can set in, producing conditions that are outside the thermodynamic
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Isotope evidence for the enrichment mechanism of molybdenum in methane-seep sediments: Implications for past seepage intensity Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-07 Meng Jin, Fang Chen, Niu Li, Jörn Peckmann, Ryan Mathur, Linda Godfrey, Duofu Chen
Methane release from marine sediments strongly influences the local seafloor environment and ecosystems, and may impact Earth’s climate system. Recent studies revealed anomalous molybdenum (Mo) enrichment in seep sediments, which was linked to methane release events. Marine seep sediments are a potential sink of Mo for the global ocean, while the mechanisms leading to local Mo enrichment are not fully
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Phosphate uptake is an essential process for rapid bone mineralization during early diagenesis – evidence from bone alteration experiments Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-06 Anna G. Kral, Thorsten Geisler, Michael Wiedenbeck, Paul Guagliardo, Thomas Tütken
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Constraining carbonate diagenesis using clumped isotope temperatures and U-Pb dating: A case study and implications for paleoelevation interpretations in western central Tibet Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-06 Lin Li, Peter DeCelles, Paul Kapp, Carmala Garzione, Jay Quade, Nitzan Yanay
Carbonate rocks are susceptible to diagenesis, and the correct identification of diagenetic features and stages are primary tasks in paleoelevation and paleoclimate studies using carbonate proxies. In this study, we apply three key parameters that include stable isotopes, clumped isotope temperatures, and U-Pb ages to identify different diagenetic stages, i.e., eogenesis, mesogenesis, and telogenesis
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New olivine morphologies in shergottites reveal complex thermal histories of martian magmas Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-06 S.A. Eckley, R.A. Ketcham, Y. Liu, A. Udry, J. Gross
Petrogenetic models of martian magmas reflect the compositional, thermal, and geodynamical evolution of its interior. Most models for shergottite meteorites, which sampled relatively young martian basalts, invoke partial melting in a mantle plume head and filtering of the magma through the crust. Olivine-phyric, poikilitic, and olivine-gabbroic shergottites contain large, Mg-rich olivine crystals that
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Volatiles in melt inclusions from lunar mare basalts: Bridging the gap in the H2O/Ce ratio between melt Inclusions in lunar pyroclastic sample 74220 and other mare samples Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-03 Xue Su, Youxue Zhang
The HO concentration and HO/Ce ratio in olivine-hosted melt inclusions are high in lunar pyroclastic sample 74220 (HO up to 1410 ppmw; HO/Ce up to 77) but lower (HO 10 to 430 ppmw; HO/Ce 0.3 to 9.4) in all other lunar samples studied before this work. The difference in HO concentration and in HO/Ce ratio is absent for other volatile elements (F, S, and Cl) in melt inclusions in 74220 and other lunar
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The role of alkaline silicate-rich fluids in Sn mineralization based on cassiterite solubility experiments Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-03 Qinxia Wang, Renzhi Zhu, Wan-Cai Li, Huaiwei Ni
It is widely accepted that the complexation of Sn with Cl in magmatic-hydrothermal fluids is critical for the formation of endogenic Sn deposits. However, Sn abundance as high as 0.4 wt% has been found in some chlorine-poor but silicate-rich fluid inclusions associated with a Sn-mineralized pegmatite. To examine the role of silicate solutes in Sn mineralization, we measured the solubility of cassiterite
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Constraints on hopanes and brGDGTs as pH proxies in peat Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-01 Valentine Schaaff, Vincent Grossi, Matthew Makou, Yannick Garcin, Pierre Deschamps, David Sebag, Benjamin Ngounou Ngatcha, Guillemette Ménot
pH is one of the major parameters governing peat functioning, and pH variations in modern peatlands affect carbon and methane production and consumption. Paleo-pH reconstructions have been limited thus far, but they could help to better understand peat functioning in variety of settings and also serve as an indirect proxy for climatic and environmental variations such as precipitation. Bacterial hopanes
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Size-dependent dynamics of the internal carbon pool drive isotopic vital effects in calcifying phytoplankton Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-04-01 Nishant Chauhan, Rosalind E.M. Rickaby
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Vivianite oxidation is not photocatalyzed Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-31 Winnie Liu, Zheming Wang, Mark Bowden, Odeta Qafoku, Kevin M. Rosso
Vivianite is a hydrous Fe(II) phosphate mineral found in anoxic environments that plays an integral role in P cycling and environmental biogeochemistry. Imbued in the vivianite literature dating as far back as 1918 is the notion that vivianite is light-sensitive and susceptible to rapid photooxidation induced entirely by solar light. However, despite an exhaustive search, to our knowledge this conventionally
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Three-dimensional textures of Ryugu samples and their implications for the evolution of aqueous alteration in the Ryugu parent body Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-30 Akira Tsuchiyama, Megumi Matsumoto, Junya Matsuno, Masahiro Yasutake, Tomoki Nakamura, Takaaki Noguchi, Akira Miyake, Kentaro Uesugi, Akihisa Takeuchi, Shota Okumura, Yuri Fujioka, Mingqi Sun, Aki Takigawa, Toru Matsumoto, Satomi Enju, Itaru Mitsukawa, Yuma Enokido, Tatsuhiko Kawamoto, Takeshi Mikouchi, Tatsuhiro Michikami, Tomoyo Morita, Mizuha Kikuiri, Kana Amano, Eiichi Kagawa, Stefano Rubino, Zelia
Samples collected from the surface/subsurface of C-type asteroid 162173 Ryugu by the Hayabusa2 mission were nondestructively analyzed in three dimensions (3D). Seventy-three small particles (approximately 10–180 µm in size) were observed using X-ray nanotomography, with an effective spatial resolution of approximately 200 nm. Detailed descriptions of these samples in terms of mineralogy, petrology
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Indium partitioning between silicate melts and magmatic fluids: implications for indium ore genesis and the tracing of magma degassing Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-30 Panlao Zhao, Zoltán Zajacz, Carter Grondahl, Alexandra Tsay, Jingwen Mao, Qiuming Cheng, Shunda Yuan
Most of the global indium resources are from deposits associated with felsic rocks. Considering that the indium concentration in the average upper crust is extremely low, magmatic-hydrothermal processes play a critical role in the enrichment and mineralization of indium. However, the extraction efficiency of indium by magmatic fluids remains unclear. We performed experiments at 800 °C, 150 MPa and
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Experimental investigation of first-row transition elements partitioning between olivine and silicate melt: Implications for lunar basalt formation Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-30 Jie-Jun Jing, Ben-Xun Su, Jasper Berndt, Hideharu Kuwahara, Wim van Westrenen
Fifteen experiments at 1 atm pressure and 1400 °C have been conducted to determine partition coefficients between olivine and silicate melt () of the first-row transition elements (FRTEs, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn), Ga and Ge in the system FeO-CaO-MgO-AlO-SiO (FCMAS). Bulk iron contents are varied between 0 and 10 wt.% FeO, and oxygen fugacity ranges from 2 log units below the iron-wüstite
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Pyrite trace element proxies for magmatic volatile influx in submarine subduction-related hydrothermal systems Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-30 Jan J. Falkenberg, Manuel Keith, Karsten M. Haase, Reiner Klemd, Martin Kutzschbach, Anna Grosche, Maria Rosa Scicchitano, Harald Strauss, Jonguk Kim
Seafloor massive sulfides are modern analogues to ancient volcanogenic massive sulfide deposits, which are particularly enriched in volatile and precious metals (e.g., Te, Au, Ag, Cu, Bi, Se) in subduction-related settings. However, the sources of metals are still poorly constrained, and it remains elusive, whether magmatic volatile influx controls their distribution in submarine hydrothermal systems
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Source and parental melts of poikilitic shergottites: Implications for martian magmatism Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-30 Evan W. O'Neal, A.M. Ostwald, A. Udry, J. Gross, M. Righter, T.J. Lapen, J. Darling, G.H. Howarth, R. Johnsen, D.R. McQuaig
Martian poikilitic shergottites are cumulate rocks that can help advance the understanding of magmatic evolution from near the base of the crust (∼10 kbar) to near-surface conditions. Through a comprehensive petrographic and geochemical study, we aim to better understand poikilitic shergottite formation and the evolution in the martian interior. A suite of poikilitic shergottites, including Northwest
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Mechanisms controlling albite dissolution/precipitation kinetics as a function of chemical affinity: New insights from experiments in 29Si spiked solutions at 150 and 180 °C Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-29 Jacques Schott, Giuseppe D. Saldi, Chen Zhu, Lei Gong, Kaiyun Chen
Knowledge of the rates of dissolution of rock-forming minerals close to equilibrium and their dependence on Δ, the Gibbs free energy of reaction, is essential for describing the temporal and spatial evolution of many environmental and engineering processes involving solid/fluid interactions. In the present study we used the isotope-doping method to quantify albite forward and net dissolution rates
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Nanoscale mechanisms of carboxyl carbon preservation during Fe(II)-induced ferrihydrite transformation Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-29 Fu Liu, Yang Lu, Zhenqing Shi
The persistence of organic carbon (OC) in natural environments is widely attributed to OC associations with minerals such as iron (Fe) minerals. Carboxyl, a critical structure of OC, can form strong complexes with Fe minerals, but it is still largely unknown about the effects of carboxyl groups on the transformation of Fe oxides and the stabilization mechanisms of OC on Fe oxides at nanoscales. In
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Aqueous alteration in icy planetesimals: The effect of outward transport of gaseous hydrogen Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-28 Takazo Shibuya, Yasuhito Sekine, Sakiko Kikuchi, Hiroyuki Kurokawa, Keisuke Fukushi, Tomoki Nakamura, Sei-ichiro Watanabe
Parent bodies of carbonaceous chondrites that initially contained metallic iron potentially exert strong reduction power during aqueous alteration to generate molecular hydrogen in excess of hydrogen solubility in water-rich fluids. The surplus hydrogen escapes from the system, which is subsequently supplied to overlying regions in planetesimals. Based on this concept, we conducted chemical equilibrium
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Controls on distributions of aluminium, manganese and cobalt in the South Atlantic Ocean along GEOTRACES transect GA10 Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-28 Xue-Gang Chen, Angela Milne, Jessica K. Klar, Martha Gledhill, Maeve C. Lohan, Yu-Te Hsieh, Gideon M. Henderson, E. Malcolm S. Woodward, Eric P. Achterberg
Trace metals (TMs) manganese (Mn), cobalt (Co), and aluminium (Al) have important geochemical and biological roles in the ocean. Here, we present full depth profiles of dissolved (d) and particulate Al, Mn, and Co along the latitude of 40 °S in the South Atlantic Ocean from the GEOTRACES GA10 cruises that operated in austral spring 2010 and summer 2011. The region is characterized by enhanced primary
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Incipient Dissolution of Emplaced Forsterite and Fayalite Records the Effects of Climate, Mineral Composition, and Crystallographic Orientation Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-28 Feldman AD, Hausrath EM, Burnley P, Rampe EB, Morris RV, Munoz J, Uyeda GH, Seward G
To investigate the effects of environment, composition, and crystal orientation on incipient surface alteration of forsterite and fayalite in a natural environment, polycrystalline forsterite and fayalite samples were emplaced in Mg/Fe-rich and Al-poor ultramafic soils under subarctic (Tablelands in Newfoundland, Canada; 3.9 ⁰C and ∼120 cm precipitation/year), Mediterranean (Klamath Mountains, California;≤12
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Young KREEP-like mare volcanism from Oceanus Procellarum Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-28 Zaicong Wang, Keqing Zong, Yiheng Li, Jiawei Li, Qi He, Zongqi Zou, Harry Becker, Frédéric Moynier, James M.D. Day, Wen Zhang, Yuqi Qian, Long Xiao, Zhaochu Hu, Zhenbing She, Hejiu Hui, Xiang Wu, Yongsheng Liu
The Moon’s mare volcanism predominantly occurs within the Procellarum KREEP Terrane (PKT), which is widely thought to be associated with KREEP components within the lunar interior. The Chang’e-5 (CE-5) mission sampled a young (2 Ga) mare basalt Em4/P58 unit of northern Oceanus Procellarum. The geochemistry of the CE-5 mare basalt enables assessment of mantle source compositions which are essential
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Recycling of crustal Os in nascent subduction zones revealed by ophiolitic boninites Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-28 Wen-Jun Hu, Mei-Fu Zhou, Chao Li, John Malpas, Zhen-Chao Wang, Jun-Jie Xu
Olivine-rich lavas in the Margi area, Cyprus, are part of the boninitic Upper Pillow Lava series of the Troodos ophiolite. Re-Os isotope compositions of both whole rock and olivine phenocrysts of these lavas have been measured to determine the initial Os/Os isotope compositions of the primary boninitic magma. The Margi lavas have high and variable whole rock Re-Os isotope compositions (Re/Os: 1.060–8
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Characterising the decay of organic metal complexes in speleothem-forming cave waters Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-27 Sebastian N. Höpker, Sebastian F.M. Breitenbach, Megan Grainger, Claudine H. Stirling, Adam Hartland
Organic metal complexes (OMCs) transport trace metals (, Co, Ni, Cu) from surface soils, via the unsaturated zone, to sites of cave carbonate (speleothem) formation. OMCs clearly imprint on speleothem trace element chemistry, but the role of kinetic factors in the signal transfer process has yet to be elucidated. We investigated whether OMCs may viably link metal concentrations in stalagmites and local
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Trace elements in zircon record changing magmatic processes and the multi-stage build-up of Archean proto-continental crust Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-27 Nadja Drabon, Heather M. Kirkpatrick, Gary R. Byerly, Joseph L. Wooden
Zircon trace element geochemistry has become an increasingly popular tool to track crustal evolution through time. This has been especially important in early-Earth settings where most of the crust has been lost, but in some fortuitous instances detrital zircons derived from that lost crust have been preserved in younger sediments. To study the formation and geochemical evolution of continental crust
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Isotopic and kinetic constraints on methane origins in Icelandic hydrothermal fluids Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-27 Andri Stefánsson, Andrea Ricci, Mark Garnett, Jóhann Gunnarsson-Robin, Barbara I. Kleine-Marshall, Samuel W. Scott, Matteo Lelli, Carolina Dantas Cardoso, Raphaël Pik, Chiara Santinelli, Shuhei Ono, Peter H. Barry, Michael W. Broadley, David Byrne, Sæmundur A. Halldórsson, Jens Fiebig
The origin of methane in hydrothermal fluids has long been a subject of debate – whether it is abiotic or biotic. In this study, we aim to unravel and quantify the sources of CH in active hydrothermal systems by adopting a holistic approach analyzing well characterized high-temperature hydrothermal fluids (∼230–310 °C) in Iceland. We employ a broad variety of geochemical and isotope indicators, encompassing
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Origin of rare earth elements in acid mine drainage traced by strontium and neodymium isotopes Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-27 Rafael León, Francisco Macías, Carlos R. Cánovas, Ricardo Millán-Becerro, Jonatan Romero-Matos, José Miguel Nieto
Acid mine drainage (AMD) generated from coal and sulfide mining has attracted much interest due to the high concentrations of rare earth elements (REE) observed. However, the origin of REE in AMD and particularly the mechanism of enrichment in medium REE remain uncertain. The combined study of Sr and Nd isotopes can be used to trace the processes that control the mobility and fractionation of REE in
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Mapping the redox state of the young Solar System using ytterbium valence state Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-27 Tahar Hammouda, Paul Frossard, Maud Boyet, Audrey Bouvier, Matthew Newville, Antonio Lanzirotti
We have determined the valence state of Ytterbium (Yb) in a collection of meteorites covering 4–5 orders of magnitude in oxygen fugacity (fO) by X-ray absorption near-edge structure (XANES) spectroscopy at the Yb L2 edge. In the studied meteorite minerals, Yb abundance was between 1 and 30 ppm. The data were obtained from merrillite grains (theoretical formula CaNaMg(PO)) from two equilibrated ordinary
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Ca isotopic gradients in epeiric marine carbonates: Diagenetic origins of and significance for Ca cycle reconstructions Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-26 C. Holmden, S.R. Kimmig, M.D. Nadeau
Marine carbonates record geochemical information on the state of Earth’s surface environment in the geological past, but recrystallization during burial can make the records difficult to interpret. Here, we report shore to basin gradients in δCa values in matrix limestone and burrow dolomite across a sequence of Late Ordovician (Katian Stage) burrow-mottled carbonates in the Williston Basin, an intracratonic
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Thermodynamic property estimations for aqueous primary, secondary, and tertiary alkylamines, benzylamines, and their corresponding aminiums across temperature and pressure are validated by measurements from experiments Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-22 Kirtland J. Robinson, Jeffrey S. Seewald, Sean P. Sylva, Kristopher M. Fecteau, Everett L. Shock
On Earth and beyond, organic chemistry often occurs in the presence of water within environments that deviate drastically from ambient conditions (25 °C and 1 bar). Accurately predicting aqueous organic reaction pathways is crucial toward understanding planetary scale processes such as the cycling of elements crucial for life (e.g., carbon and nitrogen). Advanced thermodynamic modeling can be utilized
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Mineral–water reactions in Earth’s mantle: Predictions from Born theory and ab initio molecular dynamics Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-21 Sarah J. Fowler, David M. Sherman, John P. Brodholt, Oliver T. Lord
Recent studies present compelling evidence that a free aqueous fluid phase exists within the upper mantle. Fluid may be present at depths as great as the transition zone (410–660 km) and possibly beyond. The chemical reactivity of such deep fluids can be predicted from the Born model of solvation. To use the Born model, we need to know the dielectric constant of water under mantle conditions. We have
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Partitioning of tin between mafic minerals, Fe-Ti oxides and silicate melts: Implications for tin enrichment in magmatic processes Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-20 Chunxia Wei, Xiaolin Xiong, Jintuan Wang, Fangfang Huang, Mingdi Gao
The partition coefficients of Sn (tin) between minerals and silicate melts are vital for understanding the Sn enrichment during magmatic processes related to tin-granites. However, experimentally determined values remain scarce due to the difficulty in avoiding severe Sn loss to noble metal capsules. In this study, we performed mineral/melt Sn partitioning experiments at 0.5–1.0 GPa, 850–1000 °C, and
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Refining the roles of productivity, redox, and remineralization on the cadmium isotope composition of marine sediments Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-18 Logan A. Tegler, Sune G. Nielsen, Yi Wang, Florian Scholz, Jeremy D. Owens, Larry Peterson, Maureen Auro, Christopher W. Kinsley, Phoebe Lam, Tristan J. Horner
Cadmium (Cd) has a nutrient-like distribution in the ocean, similar to the macronutrient phosphate. Significant isotope fractionation induced by the biological cycling of Cd makes it a potential tracer for nutrients and productivity. However, the Cd flux and Cd isotope composition of marine sediments may also be influenced by local redox conditions and partial remineralization of organically hosted
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Effect of terrestrial weathering on stable Sr and Ba isotope compositions of eucrites Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-16 Chang Nie, Jin-Ting Kang, Yun Jiang, Si-Jie Wang, Fang Huang, Wei-Biao Hsu
Stable strontium and barium isotopes are potential tracers for understanding planetary differentiation and the nature of the building blocks of terrestrial planets. Strontium and barium are fluid-mobile elements, but it remains unclear how terrestrial weathering affects the Sr-Ba isotopes compositions in achondrites, thus hampering the utility of Sr-Ba isotopes in cosmochemistry. In this study, we
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Dissolved rare earth elements in the North Pacific Subtropical Gyre: Lithogenic sources and water mass mixing control Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-15 Axiang Cao, Qian Liu, Jing Zhang, Alan M. Shiller, Yihua Cai, Ruifeng Zhang, Melissa Gilbert, Xianghui Guo, Zhiyu Liu
In the North Pacific Subtropical Gyre, which is one of the largest oligotrophic regions, there is a lack of information regarding the sources and transport of trace metals through water mass mixing. Rare earth elements (REEs) are essential for tracing lithogenic sources and water mass transport. In this study, we present dissolved REE concentrations and the factors controlling their distributions in
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Influence of species and stand position on isotopic and molecular composition of leaf litter during degradation in an urban mangrove forest Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-15 Sarah Louise Robin, Claude Le Milbeau, Kapeliele Gututauava, Cyril Marchand
Understanding the diagenetic processes of organic matter (OM) within mangrove forests is essential to grasp ecosystem dynamics and exchanges with adjacent ecosystems. This study investigated the influence of urban runoff on leaf litter degradation in a New Caledonian mangrove forest, subjected to urban rainwater for over 50 years. Focusing on and , our objectives were to determine factors affecting
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Temperature-controlled Se-S isotope fractionation during seawater mixing and sulfide precipitation in black smoker chimneys Geochim. Cosmochim. Acta (IF 5.0) Pub Date : 2024-03-15 Anna Grosche, Manuel Keith, Reiner Klemd, Harald Strauss, Carolina Rosca, Stephan König
Submarine hydrothermal venting leads to the formation of black smoker chimneys with complex internal zoning. These emerge through mineral precipitation under changing fluid conditions caused by variable degrees of fluid-seawater mixing. This study explores the potential of selenium (Se) isotopes as a novel tool to understand the enrichment processes and identify the sources of chalcophile elements