Showing papers in "Chemical Geology in 2013"

TL;DR: In this paper, the authors used a Bayesian approach to optimize the calculation of the coefficients in the zircon solution model, which is given by: ln D Zr = 10108 ± 32 / T K − 1.16 ± 0.15 M − 1 − 1.48 ± 0.09 where DZr is the distribution coefficient of Zr between zirton and melt and the errors are at one sigma.

TL;DR: MDS is a robust and flexible superset of PCA which makes fewer assumptions about the data, and it is shown that the statistical effect size of the Kolmogorov–Smirnov test is a viable dissimilarity measure.

TL;DR: In this article, a discriminant-function-based major-element diagrams for the tectonic discrimination of siliciclastic sediments from three main tectonics settings: island or continental arc, continental rift, and collision, have been constructed.

TL;DR: In this paper, a laser-ablation split-stream (LASS) analysis for petrochronology is presented, using dual multi-collector-single collector inductively-coupled plasma mass spectrometry.

TL;DR: In this paper, the authors studied the redox dynamics of manganese (Mn) in the sediment of Lake Zurich using precise sediment core age models, monthly long-term oxygen (O 2 ) monitoring data of the water column (1936-2010) and high-resolution XRF core scanning.

TL;DR: In this paper, the authors used Titanite U-Pb dates to understand deformation and metamorphism of typical crustal rocks during ultra-high-pressure (UHP) subduction and exhumation.

TL;DR: In this paper, the authors present a laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analysis of sulfide droplets and their host fresh mid-ocean-ridge basalt (MORB) glasses.

TL;DR: Li et al. as mentioned in this paper revisited both Cu-Au ore-bearing and barren “C-type adakitic rocks” in the Lower Yangtze River Belt (LYRB) of central eastern China, including comprehensive analyses of their in-situ zircon Hf-O isotopes, whole-rock geochemistry and Sr-Nd isotopes.

TL;DR: This paper used an earth system model of intermediate complexity that has been modified to simulate a theoretical Archean biosphere in order to explore redox heterogeneity in the late Archean surface ocean and demonstrate that oxygen oases are an expected consequence of oxygenic photosynthesis beneath an essentially O2-devoid atmosphere.

TL;DR: In this paper, the authors reviewed and re-examine isotope data from four published papers that include shale gas from the Barnett and Fayetteville Shales, and gas from fractured reservoirs in the Appalachians (Burruss and Laughrey, 2010) and the Foothills of the Western Canada Sedimentary Basin (WCSB) (Tilley et al., 2011).

TL;DR: In this article, the authors integrate chemo-, litho-, and sequence-stratigraphy of fossiliferous Ediacaran strata in northwestern Canada and conclude that a purported shift in Fe speciation in the Sheepbed Formation significantly predates the shift recorded above the ca. 582 Ma Gaskiers glaciation in Newfoundland and the first appearance of Ediacara biota.

TL;DR: In this paper, a complete trend of carbon isotopic composition (δ 13 C) variations in methane and ethane with maturity is proposed that is based on the indigenous mixing mechanism.

TL;DR: In this paper, the incorporation and early diagenetic evolution of U isotopes in shallow Bahamian carbonate sediments was examined, and it was shown that authigenic accumulation of U under open-system sulfidic pore water conditions strongly affects the bulk U concentrations and 238U/235U ratios.

TL;DR: In this article, a multi-proxy study of Mo, U and Fe isotopes together with Fe speciation of black shales and siltstones from the upper Zaonega Formation of the Onega Basin in Karelia is presented.

TL;DR: A 6.7 million year record of marine sedimentation through the Permo Triassic Biotic Crisis shows notable shifts in mercury concentrations that varied over an order of magnitude (0.002 to 0.116μg/g) as discussed by the authors.

TL;DR: In this article, the authors summarize the stratigraphic context of Neoproterozoic iron formation and its geographic and temporal distribution and conclude that most NIF is associated with the earlier Cryogenian (Sturtian) glacial epoch.

TL;DR: The isotopic composition of species-specific atmospheric mercury (Hg) was investigated in the coastal environment of Grand Bay, Mississippi, USA as discussed by the authors, where Hg 0 (g), Hg II (g) and Hg (p) were collected individually, and analyzed for isotope composition.

TL;DR: The KantishnaHills miningdistrict of interior Alaska, USA, located within Denali National Park and Preserve, con- tains a number of antimony lode deposits, including Alaska's historically largest antimony producer, the Stam- pede mine.

TL;DR: In this paper, the authors examined the effects of microbial sulfate reduction and humic acid on arsenic mobilization via a series of advective-flow column experiments and found that the presence of high concentrations of Humic acid alone alone did not enhance the overall extent of arsenic release from either the abiotic or the inoculated (sulfate reducing) columns.

TL;DR: In this paper, the authors report sediment and pore water Mo, U, Mn and Fe data for a euxinic basin with a short seawater residence time; the weakly restricted Gotland Deep in the Baltic waters.

TL;DR: In this paper, the authors reported improved techniques for measuring sulfur isotopes on the MC-ICP-MS Neptune Plus (Thermo Fischer Scientific) using a heated spray chamber coupled to a desolvating membrane.

TL;DR: In this article, a global regression analysis was performed to calibrate a model of equilibrium between clinopyroxene and coexisting melt compositions from Mt Etna volcano, where the degree of disequilibrium was determined through the comparison between components "predicted" via regression analyses of cliniciansopyroxenes and liquid pairs in equilibrium conditions, with those "measured" in the analyzed crystals.

TL;DR: In this paper, the authors used a conceptual model to explain the nuclear volume effect observed between Hg liquid and Hg vapor under equilibrium conditions, and showed that the average ratio of NVE MIF of the two odd isotopes (Δ 199 Hg/Δ 201 Hg) in the vapor phase was 1.59 ± 0.05 (2SE).

TL;DR: The Zhengga diorite-gabbro suite from the Gangdese area has been studied in this paper, and the results show that the parent magmas of the Zhengga gabbros were generated by hydrous partial melting of lithospheric mantle metasomatized by sediment melts/fluids.

TL;DR: In this paper, the authors describe the mobility and fractionation of REEs in two deep (up to 30 m) tropical weathering profiles developed on two granites from the Kuala Lumpur pluton, Malaysia, sampled at Cheras and Rawang.

TL;DR: In this paper, the accuracy of oxygen isotope fractionation equations for aquatic paleotemperatures was evaluated against the well constrained carbonate-water fractionation between calcium carbonate and water, and the results showed that the proposed equation consistently yields temperatures from bioapatites equivalent to those from coexisting carbonates.

TL;DR: In this article, the authors present evidence to suggest that melts from the igneous layer in the stagnant Pacific slab contributed to the source composition of basalts erupted in eastern China, but they do not identify the source material.

TL;DR: In this article, atom probe tomography (APT) and energy-filtered transmission electron microscopy (EFTEM) were applied to a borosilicate glass sample of nuclear interest altered for 25.75 years at 90°C in a confined granitic medium in order to better understand the rate-limiting mechanisms under conditions representative of a deep geological repository for vitrified radioactive waste.

TL;DR: In this article, the authors stress on the fact that biomineralization is often the first step of fossilization and produces particular chemical, structural and morphological features that can be preserved in fossil biominerals or microfossils.

TL;DR: In this article, an initial extended X-ray absorption fine structure (EXAFS) spectroscopy was used to determine the Hg species and to estimate the relative proportions of these species present in Hg-bearing wastes from the Wanshan Hg mine (WSMM) of the eastern Guizhou province.