Abstract Most conventional statistical methods aiming at defining geochemical concentration thresholds for separating anomalies from background have limited effectiveness in areas with complex geological settings and variable lithology. In this paper, median+2MAD as a method of exploratory data analysis (EDA) and concentration-area (C-A) fractal model as two effective approaches in separation g...

A comparison is made of the probability of the process of two neutrino double beta decay for Se in direct (counter) and geochemical experiments. It is shown that the probability is systematically lower in geochemical experiments, which characterize the probability of ββ(2ν) decay a few billions years ago. The experimental data for Te are also analyzed. It is shown that geochemical measurements ...

Geochemical mapping programs carried out by the Geological Survey of Sweden (SGU) have generated large databases containing information on the concentrations of chemical elements in rocks, surface sediments and biogeochemical materials. Regional geochemical data being imprecise, multivariate, spatially auto-correlated and non-normally distributed pose specific problems to the choice of data ana...

Tabular dunites in the Josephine peridotite of southwestern Oregon represent conduits for melt extraction from the upper mantle. The amount of melt trapped within these channels during cooling and exhumation of the peridotite massif was calculated using a mass-balance approach. These calculations suggest that no more than 0·1^0·2 vol. % melt could have been trapped within these dunites after cr...

The paper “Anaerobic oxidation of methane in grassland soils used for cattle husbandry” reports interesting laboratory data showing methane oxidation in an agricultural soil under anaerobic conditions. Moreover, by using 13CH4 the authors are able to trace the carbon into PLFA and make some interpretation on methanotrophic sources. In concert with geochemical data and calculations, it appears p...

The geochemical history of an upper deltaic plain pending tidal wetland restoration was reconstructed to assess remobilization of redox-sensitive constituents in sediment, identify depositional processes promoting geochemical retention, and determine the extent of contamination with Hg, As, Pb, Cu, and Zn. Three 12-14-m sediment cores were analyzed for bulk sediment geochemistry using ICP-AES. ...

Differences in the viscosity of the earth’s upper mantle beneath the western US (f 10–10 Pa s) and global average values based on glacial isostatic adjustment and other data (f 10–10 Pa s) are generally ascribed to differences in temperature. We compile geochemical data on the water contents of western US lavas and mantle xenoliths, compare these data to water solubility in olivine, and calcula...

central tenet of lunar science is that the Moon was surrounded by a huge ocean of magma when it formed. Originally thought to be a few hundred kilometers deep, lunar scientists now think that the entire Moon was initially molten. Numerous geochemical models have been constructed for the crystallization of the magma ocean. All the calculations use computer programs based on experimental data, bu...

We combine path-integral Monte Carlo methods with high-quality potential energy surfaces to compute equilibrium isotope effects in a variety of systems relevant to 'clumped' isotope analysis and isotope geochemistry, including CO2, N2O, methane, and propane. Through a systematic study of heavy-atom isotope-exchange reactions, we quantify and analyze errors that arise in the widely used Urey mod...

Submarine groundwater discharge (SGD) nutrient fluxes from un-sewered suburban landscapes pose a significant eutrophication risk to coastal waters. In unconsolidated coastal aquifers, nutrients recharged to groundwater undergo diffuse discharge to the coastline during SGD. Defining pathways of nutrient attenuation is required for land management professionals to take effective nutrient remediat...