biglar permo-triassic bauxite deposit is located in ~15 km northwest of abgarm, southwest of ghazvin province, west of central iran. it consists of 8 stratiform and discontinuous bauxite lenses lying along the contact of ruteh (permian) and elika (triassic) carbonate formations. petrographically, the bauxite ores exhibit collomorphic-fluidal, pseudo-breccia, pseudo-porphyritic, panidio-morphic-...

The geochemical model PHREEQC is capable of simulating a wide range of equilibrium reactions between water and minerals, ion exchangers, surface complexes, solid solutions, and gases. It also has a general kinetic formulation that allows modeling of nonequilibrium mineral dissolution and precipitation, microbial reactions, decomposition of organic compounds, and other kinetic reactions. To faci...

[1] The late Paleocene to the early Eocene ( 58–52 Ma) was marked by significant changes in global climate and carbon cycling. The evidence for these changes includes stable isotope records that reveal prominent decreases in ı18O and ı13C, suggesting a rise in Earth’s surface temperature ( 4ıC) and a drop in net carbon output from the ocean and atmosphere. Concurrently, deep-sea carbonate recor...

The potential for human exposure to arsenic (As), a group A carcinogen, has increased tremendously because of the encroachment of suburban areas into former agricultural lands, where arsenical pesticides were used extensively prior to the 1990s. Many baseline risk assessments of As-enriched sites assume that all (100%) As present in the soil is bioavailable because of the high expenses and logi...

The role of eroding landscapes in organic carbon stabilization operating as C sinks or sources has been frequently discussed, but the underlying mechanisms are not fully understood. Our analysis aims to clarify the effects of soil redistribution on physical and biogeochemical soil organic carbon (SOC) stabilization mechanisms along a hillslope transect. The observed mineralogical differences se...

In marine sediments archaea often constitute a considerable part of the microbial community, of which the Deep Sea Archaeal Group (DSAG) is one of the most predominant. Despite their high abundance no members from this archaeal group have so far been characterized and thus their metabolism is unknown. Here we show that the relative abundance of DSAG marker genes can be correlated with geochemic...

Statistical studies on the correlation analysis and multiple linear stepwise regression analyses based on the different geochemical fractions of metals (Cd, Cu, Pb and Zn) in the sediments of the Straits of Malacca were conducted. Significant (P< 0.001) correlation matrices were found among total concentrations of Cd, Cu, Pb and Zn indicating that they had a common source of anthropogenic origi...

This study assessed the geochemical impact of mine tailings reclamation on the quality of soils from the AngloGold Concession, Obuasi, Ghana. Soil samples from mine tailings reclamation sites were evaluated for the concentrations of plant nutrients and trace metals. Contaminations of trace metals, using geochemical pollution indices were used to assess possible effects on agriculture and liveli...

Tailings deposits from gold and uranium (U) mining in the Witwatersrand basin often contain elevated levels of radioactive and chemo-toxic heavy metals. Through seepage, dissolved U and other metals migrate from tailings deposits via groundwater into adjacent fluvial systems. The subsequent transport through flowing surface water is one of the most effective pathways of distributing contaminant...