Showing papers in "Chemical Geology in 2014"

TL;DR: In this paper, the authors present a general approach to common Pb correction in U-Pb LA-ICP-MS dating using a modified version of the VizualAge UcomPb data reduction package for Iolite.

TL;DR: A review of the mechanisms of uranium bioreduction and phosphate biomineralisation and their suitability to facilitate long-term precipitation of uranium from groundwater, with particular focus on in situ trials at the US Department of Energy field sites is presented in this article.

TL;DR: In this article, the rare earths and yttrium (REY) inventory of marine Fe-Mn (oxyhydr)oxide deposits is used to discriminate between different types of precipitates, regardless of their diverse mineralogical composition.

TL;DR: In this paper, the mafic index of alteration (MIA) was proposed to quantify the net loss of the mobile major elements (Ca, Mg, Na, K +/- Fe) relative to the immobile major elements(Al +/- Fe).

TL;DR: In this paper, the mechanism of the transformation of one solid phase to another and the role of fluids is discussed. But the authors focus on the interaction of minerals with CO2-saturated water, the durability of nuclear waste materials, the remediation of polluted water, and mineral reactions that can destroy our stone-based cultural heritage.

TL;DR: In this article, the authors present a set of guidelines that can be adopted to ensure that reliable Hf isotopic data are obtained by this technique and discuss a number of potential pitfalls vis-a-vis the assignment of the incorrect age to the measured isotope composition.

TL;DR: In this article, a model that considers prominent first-order factors is compiled step by step and the implied spatial variability in weathering is explored, and the observed variation of fluxes is discussed in context of observed data from large rivers globally.

TL;DR: In this article, in situ measurements of Sr and Nd isotopic compositions of eleven apatite reference materials (AP1, AP2, Durango, MAD, Otter Lake, NW-1, Slyudyanka, UWA- 1, Mud Tank, McClure Mountain and SDG) commonly used in U-Th-Pb geochronology were conducted.

TL;DR: Early Triassic syn-collisional granitoids with mafic magmatic enclaves (MMEs) crop out along the entire East Kunlun Orogenic belt (EKOB) at the northern margin of the Tibetan Plateau as mentioned in this paper.

TL;DR: In this article, the Al-in-olivine thermometer was used to estimate the maximum crystallization temperature of mantle-derived melts, which provides constraints on the minimum temperature of their mantle source regions.

TL;DR: In this article, the applicability of Fe-based redox proxies in carbonates through three approaches is explored: modern marine sediments, with an average Fe/Al ratio of 0.55 ± 0.11, with some higher values potentially being attributable to steady-state early diagenetic remobilization of Fe towards the sediment-water interface.

TL;DR: In this paper, the authors present an integrated mineralogical-geochemical database on fine-grained sediments transported by all major rivers of southern Africa, including the Zambezi, Okavango, Limpopo, Olifants, Orange and Kunene.

TL;DR: In this paper, it is shown that the dissolution of Fe-oxide grain coatings and the release of Fe to solution is important in stabilising insoluble Fe-Mg-Ca carbonate minerals but the rate limiting step for carbonate mineral precipitation is the transport of CO2-charged brines and silicate mineral dissolution rates.

TL;DR: The role of extracellular polymeric substances (EPSs) in metal adsorption has been extensively studied in the literature as mentioned in this paper, with the focus on bacterial and cyanobacterial EPSs.

TL;DR: In this paper, the authors present a method for precise measurement of Mg isotope ratios for low-Mg rock samples (where MgO b1 wt.%) by multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS).

TL;DR: Nanogeochemistry is a relatively young research field, and much remains to be explored as mentioned in this paper, and there is also a need for developing experimental and modeling techniques to extrapolate the knowledge obtained from simple model systems to complex natural systems.

TL;DR: In this article, the initial results of a scientific drilling project to recover core and pressurized fluid samples from a natural CO2 reservoir, near the town of Green River, Utah, were presented.

TL;DR: In this article, the authors evaluated the performance of a high-temperature sample digestion using inverse aqua regia in closed glass vessels, such as Carius tubes or a high pressure asher system (HPA).

TL;DR: In this paper, the role of each mineral species in the bulk isotopic compositions of bedloads and suspended loads sampled at the outflow of the Ganga River that drains the Himalayan mountain range was analyzed.

TL;DR: Authigenic carbonates that form at marine hydrocarbon seeps provide a unique geological archive of past local environmental conditions and pore fluid geochemistry as discussed by the authors, however, the mechanisms accounting for such anomalies remain poorly constrained.

TL;DR: The presence of nanoparticulate pyrite is reported in hydrothermal emissions from Rainbow, TAG and Snakepit on the Mid-Atlantic Ridge (MAR) when coupled with previously collected data from East Pacific Rise 9°N (EPR) and Lau Basin this article.

TL;DR: In this article, the results showed that high amounts of Fe(II) are complexed with organic matter (OM) and especially with humic acids (HAs) remains poorly characterized in the literature.

TL;DR: In this article, the age bias effects of an additional source of apatite He age dispersion observed in some cases: U-Th-rich grain boundary phases (GBPs) precipitated on apatitic crystal surfaces.

TL;DR: Bonnand et al. as mentioned in this paper investigated the pathway of chromium from its mobilization on land and along its riverine transport in a subtropical region of South America (Misiones Province, Argentina), in an attempt to link Cr stable isotope compositions recently measured in seawater with signals prevailing in rivers and, ultimately, with Cr isotope effects observed during oxidative surface weathering in subropical red soils.

TL;DR: Isotope geochemistry is in the midst of a remarkable period of innovation and discovery as mentioned in this paper ; the last decade (or so) has seen the emergence of ‘nontraditional’ stable isotopes of metals (i.e., variations in isotopic compositions of Mg, Fe, Cu, etc.), a great expansion of mass-independent isotope geochemical, and new capabilities for measurements of position-specific isotope effects in organic compounds.

TL;DR: In this paper, a power-law relationship between reactive surface area and porosity was investigated in a single pass injection of CO2-charged brine into nine dolomite cores to examine fluid-rock reactions in dolombite reservoirs under geologic carbon sequestration conditions.

TL;DR: In this paper, a combination of laser ablation, multi-collector, inductively-coupledplasma, mass-spectrometry (LA-MC-ICP-MS) and thermal ionization multicollector mass spectrometric (TIMS) was used to date sedimentary carbonates using U-Pb method.

TL;DR: In this paper, the authors developed parameterized lattice strain models for rare earth element partitioning among mantle minerals (olivine, orthopyroxene and olivine) using mineral-melt partitioning models that were calibrated against experimentally determined high quality mineral−melt REE partition coefficients.

TL;DR: Partition coefficients of Mg and Sr (KMg and KSr) between calcite and fluid were determined in crystals grown under different rates (V), where V is defined as the crystal extension per unit of time (nm/s) as discussed by the authors.

TL;DR: The effect of the anhydrous composition on the solubilities of H 2 O and CO 2 in mafic melts varying from MORB to nephelinite was investigated experimentally between 50 and 500 MPa at 1200 to 1250 °C as discussed by the authors.