Showing papers in "Chemical Geology in 2019"

TL;DR: In this paper, the authors present oxygen (∆17O, δ18O), and sulfur (33S and 34S) isotope records of Proterozoic sulfate from currently available data together with new measurements of 313 samples from 33 different formations bearing Earth's earliest unambiguous evaporites at 2.4 Ga through to Ediacaran aged deposits.

TL;DR: In this paper, the authors examine three global databases of rivers and springs draining carbonate regions under various climate conditions (from −15°C to +30°C) and show that carbonate weathering intensity depends upon land temperature according to a boomerang-type relationship, with maximum dissolution between 10 and 15°C.

TL;DR: In this paper, a unified model for calcium sulfate crystallization is proposed, integrating both the classical and non-classical perspectives on crystallization, and the phase stability and transformations taking place in the CaSO4-H2O system.

TL;DR: In this article, the authors presented whole rock major-trace element geochemistry, Sr and Nd isotope, K-feldspar common Pb isotopes, along with in-situ zircon U-Pb ages and Hf isotope data from the granitoids and the greenstone volcanic rocks to characterize their source(s) and to constrain the evolution of the Paleoarchean continental crust.

TL;DR: In this paper, the authors argue that known organic ligands are too weak or too scarce to capture more than minor amounts of Mo from seawater, especially in competition with sulfide.

TL;DR: In this article, the authors reviewed contemporary research of soil processes and ecosystems service delivery in Chinese karst ecosystems, with an emphasis on soil degradation and the potential for ecosystem recovery through sustainable management.

TL;DR: In this article, the adsorption of complete rare earth elements (REEs) in the weathered crust elution-deposited REE deposits was investigated under different pH levels and ionic strengths.

TL;DR: In this paper, a multi-technique assessment of rare earth and other trace elements in ooid sands from the modern Great Bahama Bank (GBB)-marine and Great Salt Lake (GSL-continental) based on strong acid (hydrofluoric and nitric) and weak acid (acetic) digestions, as well as laser ablation (LA) of ooid cortices and nuclei was presented.

TL;DR: Conway et al. as discussed by the authors presented a detailed mineralogical and crystallographic analysis of barite from size-fractionated particulate material collected using multiple unit large volume in-situ filtration systems in the North Atlantic and the Southern Ocean.

TL;DR: In this article, the origin, composition and pressure-temperature conditions of fluids involved in the W-Sn ore-forming processes have been investigated by microthermometry, Raman spectroscopy, LA-ICPMS, hydrogen isotope analyses of fluid inclusions and oxygen isotope analysis of minerals from the Maoping and Piaotang W-sn deposits.

TL;DR: In this article, a thin film of solution flew down an inclined marble or glass plate, and the authors used a Rayleigh fractionation model to determine stable carbon and oxygen isotope fractionation between the major involved species of the carbonate system (HCO3−, CO2, CaCO3 and H2O).

TL;DR: In this paper, global analyses of runoff from large-scale drainage regions as well as 76 individual river basins with large dissolved riverine 87Sr/86Sr and the average bedrock age of drainage regions and individual basin basins were performed.

TL;DR: In this paper, the solubility of nesquehonite and dypingite was evaluated using constant-temperature, batch-reactor experiments, and the results showed that the transformation from nesque-honite to dypingsite was temperature-dependent, and was complete within 57 days at 25°C and 20 days at 35°C.

TL;DR: In this paper, a data set of pyrite sulfur isotopes (δ34Spy) derived from 60-m drilled core sediments deposited on the inner shelf of the East China Sea since 16.5

TL;DR: In this paper, the authors show that rare earth elements (REE) and yttrium (Y) are found to be extremely enriched in some pelagic sediments, which could be an important resource for REY in the future.

TL;DR: In this article, it was shown that metamorphosed gabbroic, leucogabbroidic and anorthositic rocks of the South Daltons area, in the western part of the Shaw Granitic Complex, formed at 3.59-3.58

TL;DR: In this paper, the authors examined the release of organic carbon (OC) with ferrihydrite (Fh) during the abiotic reduction of FOA by hydroxylamine hydrochloride, to elucidate processes regulating the stability of OC during the redox processes.

TL;DR: In this article, the reproducibility of stable K isotope geochemistry for 23 commercially available international reference materials, including igneous, sedimentary, and metamorphic rocks, as well as an in-house seawater standard, was reported.

TL;DR: In this article, an experimental approach is presented to quantify how chemical abrasion affects the crystal structure and the chemical composition of zircon as well as its U Pb age.

TL;DR: In this paper, a meridional transect of dissolved Cd and δ114Cd from Japanese GEOTRACES section GP19 along 170°W from 64°S in the Southern Ocean to the equatorial Pacific is presented.

TL;DR: Conway et al. as mentioned in this paper investigated the response of Zn and Ni and their isotopes to natural Fe fertilization from Southern Ocean islands, using samples collected during the KEOPS-2 (Oct-Nov 2011) program in the early austral spring near the Kerguelen plateau, Indian Sector of the Southern Ocean.

TL;DR: The results of 15 partitioning experiments confirm that Dmetalfluid/melt values depend strongly on the melt and fluid composition, with the greatest metal affinities for the fluid phase shown in the experiments with high-Cl fluids, and the most fractionated melts as mentioned in this paper.

TL;DR: In this paper, a detailed analysis indicates that host rock leaching alone cannot explain the observed arsenic anomaly, and substantial contribution of arsenic from the underlying magma chambers is postulated, which are likely mantle-derived intrusions that have been severely contaminated by the very thick crustal material below southern Tibet, possibly including deep-seated arsenic-rich sedimentary rocks.

TL;DR: In this paper, the relationship between the crystal chemistry (structural disordering, oxygen vacancy) and semiconducting property (optical absorbance, band structure, photocatalytic activity) of spinel ferrites was investigated.

TL;DR: In this paper, the 253 Plus™ gas source mass spectrometer equipped with Faraday cups and 1013 Ω resistors can perform combined ∆47 and ∆48 analyses on carbonates with external reproducibilities (1SD) of 0.010 and 0.030, respectively.

TL;DR: In this paper, the authors employ micro-analysis of REE-rich accessory minerals to shed light on the evolution of a key tonalitic gneiss sample from southern West Greenland that displays the apparent Hf Nd isotope decoupling.

TL;DR: In this paper, the redistribution and transformation of arsenic (As) during the Fe(II)-catalyzed transformation of As-adsorbed ferrihydrite remains unclear.

TL;DR: In this article, an investigation of granite and its overlying regolith is conducted in South China's largest S-type granite terrain (Darongshan, Guangxi) to improve the understanding of critical factors that control the formation of REE-rich granite regolith, especially for those related to weathering.

TL;DR: In this article, an empirical equation relating Zr solubility with silicate melt composition and absolute temperature T: log Zr (ppm) was derived, where T is the ratio of the oxide mole fractions in the melts.

TL;DR: In this article, the authors investigate the mechanisms that control release of Fe from shelf sediments and its lateral transport (shuttling) in oxic and hypoxic waters on the northwestern Black Sea shelf.