Showing papers in "Geochimica et Cosmochimica Acta in 2020"

TL;DR: In this paper, the authors proposed an approach based on recognition of compound covariation patterns among pairs of elemental redox proxies within a redox framework based on three key thresholds: (1) the Re4+/Re3− couple near the suboxidized/subreduced boundary of the suboxic zone, (2) the U6+/U4+ couple in the middle of a subreduced zone, and (3) the SO42−/H2S couple at the sub-euxinic boundary.

TL;DR: This paper explored the use of three elemental ratios for paleosalinity reconstruction: boron/gallium (B/Ga), strontium/barium (Sr/Ba), and sulfur/total organic carbon (S/TOC) ratios.

TL;DR: In this article, the adsorption of dissolved cadmium, Cd(II), under seawater-like conditions to the marine cyanobacterium Synechococcus sp.

TL;DR: In this article, a sulfur-based mix-to-greedy bio-reduction process is demonstrated to be effective to detoxify Cr(VI), with a removal efficiency of 95.5% within 48'h at an initial concentration of 50'mg/L.

TL;DR: In this article, the relative abundances of refractory lithophile elements in the bulk silicate Mars (BSM) at 2.26 times higher than that in CI carbonaceous chondrites.

TL;DR: In this paper, the authors use Bayesian statistics to calibrate the relationship of the 5-methyl brGDGTs (MBT′5Me) and mean annual air temperature (MAAT), and show that soils at mid-latitudes with temperature seasonalities >20°C are not well described by the BayMBT model.

TL;DR: In this paper, the authors examined the spatial imprint of climate-related processes in speleothem δ13C values deposited post-1900 CE, a period during which global temperature and climate data is readily available.

TL;DR: In this article, an assessment of the likely number of distinct source asteroids sampled by meteorites and related extraterrestrial materials has been conducted and the results of this survey indicate that there are between 95 and 148 parent bodies represented in our sample collections.

TL;DR: In this paper, the authors report µ182W values (the deviation of a sample from that of laboratory standards, in parts per million) and corresponding 3He/4He ratios for rocks from 15 different hotspots.

TL;DR: In this article, chemical weathering and porosity profiles from catchments developed on marine shale located in Pennsylvania, USA, SSHCZO, California, USA (Eel River Critical Zone Observatory, ERCZO); and Taiwan (Fushan Experimental Forest).

TL;DR: In this article, a critical labile Fe(III)-oxide nanomineral was identified and quantified using a selective extractant, which was formed by the oxidation of aqueous Fe(II) on the Fh surface.

TL;DR: In this article, isotope fractionation of molybdenum (Mo) and uranium (U) during their removal from seawater and deposition into sediments by investigating sites at various depths of the presently two largest restricted anoxic oceanic basins: The Black Sea and the Cariaco Basin.

TL;DR: In the Hellisheiði geothermal power plant, the authors of as discussed by the authors showed that the injection of CO2 and H2S into basaltic basalts can lead to the formation of stable carbonate and sulfide minerals, and that sulfide precipitation is not limited by the availability of Fe or by the consumption of Fe by other secondary minerals.

TL;DR: In this paper, K isotope compositions of profiles through saprolites developed on a diabase in South Carolina, U.S.A., and on a granite in Guangdong, China, allow characterization of the behavior of K isotopes during continental weathering.

TL;DR: In this article, a set of carbonaceous and ordinary chondrites, including previously analyzed and new samples analyzed after the powdered samples were degassed under vacuum at 120°C for 48 hours to remove adsorbed atmospheric water.

TL;DR: In this article, the authors use thermodynamic models to predict S isotope fractionation for geologically realistic hydrothermal fluids and attempt to disentangle the effects of fluid sources, physico-chemical evolution and S mineral disequilibrium.

TL;DR: In this paper, the authors examined the patterns and controls of kinetic clumped isotope fractionations (i.e., Δ47, Δ48 and Δ49) in the DIC-H2O-CO2 system through first-principles theoretical calculations and numerical modeling (IsoDIC), and explore their implications for the carbonate clumping isotope thermometer.

TL;DR: In this article, the authors employed a suite of techniques to elucidate the underlying mechanisms accounting for the temporal changes of As(V) and C distributions and speciation on Fe oxides during the Fe(II)-induced ferrihydrite transformation process.

TL;DR: In this paper, a micro-analytical approach that combines petrographic observations with in situ LA-ICP-MS analyses and trace element mapping is presented to define the key ore-forming processes of Au and Te in the Cripple Creek epithermal complex.

TL;DR: A critical review of the U isotope proxy in marine carbonates with a focus on the current problems and areas where future work is needed to further develop this proxy can be found in this article.

TL;DR: In this paper, isothermal and undercooling experiments were conducted on one of the most primitive trachybasalts from Mt. Etna volcano in order to examine the crystallization mechanisms controlling the textural and compositional variability of clinopyroxene.

TL;DR: In this article, the authors used radium isotopes and related nutrient fluxes at the local scale in Jiaozhou Bay (JZB), a typical Chinese system that is experiencing rapid urban and industrial development.

TL;DR: In this article, a diffusion-reaction model was used to evaluate the effects of variations in watermass chemistry and sedimentation rate on authigenic trace-metal enrichment in modern Black Sea sediments and North American Devonian-Carboniferous boundary (DCB) black shales.

TL;DR: In this paper, the authors presented a systematic study of newly found dikes, including minette, aplite, granodiorite porphyry and granite porphyries, which are widespread from the southern Lhasa terrane, across the Yarlung Tsangpo suture zone (YTSZ) and into the Tethyan Himalaya.

TL;DR: In this paper, the influence of calcite precipitation on speleothem trace element records was investigated using ten cave monitoring calcite and drip water datasets, and it was shown that calcite calcite DSr shows a positive correlation with the calcite Mg/Ca ratio.

TL;DR: In this paper, the authors coupled solid phase geochemistry to measurements of porewater chemistry (to ∼1 m), CO2 and CH4 production in sediments and efflux to the atmosphere in a temperate tidal salt marsh for over one year to capture seasonal patterns within two vegetation zones of the marsh landscape that have distinct biogeochemical and hydrologic conditions.

TL;DR: In this paper, the authors analyzed 14 species of planktonic foraminifers in sediment surface samples from 13 sites, covering a growth temperature range of ∼0-28°C.

TL;DR: In this article, the authors focus on the moderately volatile element, potassium, and report the K elemental abundances and isotopic compositions (δ41K relative to NIST SRM 3141a) for nineteen Apollo lunar rocks and lunar meteorites (twenty-two subsamples), spanning all major geochemical and petrologic types of lunar materials.

TL;DR: Grewal et al. as discussed by the authors presented SIMS and vibrational spectroscopy (FTIR and Raman) data, determining C solubility, H content, and speciation of mixed C-O-N-H volatiles in graphite saturated silicate glasses from high P (1-7 GPa)-T (1500-2200

TL;DR: In this article, the quantity, distributions, and isotopic abundances of fire-derived polycyclic aromatic hydrocarbons (PAHs) were influenced by fuel types, burn conditions, and also phase.