Two hundred and fifty-two million years ago, life on Earth nearly vanished [1]. So many marine animal species disappeared—more than 90 percent—that the event, known as the end-Permian extinction, qualifies as the most severe mass extinction in the geologic record. Unlike the later demise of the dinosaurs, the end-Permian extinction is not linked to a meteor impact. Yet it is unquestionably asso...

Palaeoproterozoic sedimentary basins of north-eastern and central-eastern Australia are host to large amounts of variably deformed and metamorphosed Fe-rich tholeiitic rocks. Emplacement and/or extrusion of the mafic rocks occurred during one or more episodes of crustal thinning relating to a period of regional extension and sedimentation across Palaeoproterozoic northeastern Australia (ca. 173...

A large regional geochemical data set of O-horizon samples from a 188,000 km2 area in the European Arctic, analysed for 38 chemical elements, pH, electrical conductivity (both in a water extraction) and loss on ignition (LOI, 480 oC), was used to test the influence of different variants of cluster analysis on the results obtained. Due to the nature of regional geochemical data (neither normal n...

The Nanxiong Basin (Guangdong Province, China) preserves the most complete Asian stratigraphic record of the Cretaceous-Paleogene (K/Pg) boundary extinction and the subsequent Paleocene mammalian radiation. Despite extensive study, the precise placement of the K/Pg boundary in the Nanxiong Basin sequence has been controversial, and the timing of subsequent mammalian turnover is poorly constrain...

This paper presents geochemical data from a blanket peat located close to a Bronze Age copper mine on the northern slopes of the Ystwyth valley, Ceredigion, mid-Wales, UK. The research objective was to explore the possibility that the peat contained a geochemical record of the pollution generateD by mining activity. Four peat monoliths were extracted from the blanket peat to reconstruct the pol...

Advances in drilling technologies and production strategies such as horizontal drilling and hydraulic fracturing have significantly improved the production of natural gas by stimulating fluid flow from wells. Since 2008, these technological developments have spurred exponential growth of gas well drilling across the U.S. While the new drilling for shale gas and hydraulic fracturing technologies...

Regional geochemical survey (RGS) results for the lskut River (1048). Telegraph Creek (104G) and Tulsequah (104K) areas were released in July 1988. The release consists of chemical and physical data for sediment and water samples collected from more than 2700 streams over an area of 35 000 square kilometres underlain by 50 different rock units. For each sample over 40 variables were recorded in...

The performance assessment of a geological repository for radioactive waste requires quantifying the geochemical evolution of the bentonite engineered barrier. This barrier will be exposed to coupled thermal (T), hydrodynamic (H), mechanical (M) and chemical (C) processes. This paper presents a coupled THC model of the FEBEX (Full-scale Engineered Barrier EXperiment) in situ test which accounts...

In recent years, researchers have focused on modeling of multicomponent reactive transport and have developed models to study the mobility of potentially toxic heavy metals in the subsurface. In this study, a mathematical model for understanding the fate of a typical heavy metal (lead) in unsaturated soil is developed. The entire modeling activity comprises of three parts. During the first part...