Ž . The vesicular, fine-grained A horizon Av is the widespread, ubiquitous surficial horizon of desert soils in diverse landforms and parent materials of varying ages. Now known to form mostly through accumulation of eolian dust, recent studies show that dust accumulation and concomitant soil development are genetically linked to stone pavement formation. Changes in the magnitude of eolian acti...

Excavations in a playa along the 1992 rupture of the Emerson fault reveal evidence of two paleoseismic events, with only one large prehistoric rupture in the past 15 millennia. Accelerator mass spectrometer radiocarbon ages of charcoal from playa sediments and from faultscarp colluvium directly beneath the playa beds indicate that the last large prehistoric slip event occurred about 9000 ka. Tr...

[1] Oxygen isotope data provide a key test of general circulation models (GCMs) for the Last Glacial Maximum (LGM) in North America, which have otherwise proved difficult to validate. High dO pedogenic carbonates in central Wyoming have been interpreted to indicate increased summer precipitation sourced from the Gulf of Mexico. Here we show that tooth enamel dO of large mammals, which is strong...

In the deltaic plain of the Ganges-Meghna-Brahmaputra rivers, arsenic concentrations in groundwater commonly exceed regulatory limits (50 μg l) because FeOOH is microbially reduced and releases its sorbed load of arsenic to groundwater. Neither pyrite oxidation nor competitive exchange with fertilizer-phosphate contribute to arsenic pollution. The most intense reduction, and so severest polluti...

Pedogenic carbonate samples collected from three Lower Cretaceous (Aptian–Albian) fossil localities in Texas and Oklahoma were analyzed to develop paleoatmospheric pCO2 estimates by measuring the stable carbon isotopes of pedogenic calcite their co-existing occluded organic matter. Calcite ?13C values ranged ?10.9‰ ?4.4‰ while matter ?27.3‰ ?21.1‰. These isotope measurements combined with tempe...

Soil carbonate (SIC) exceeds organic carbon (SOC) greatly in arid lands, thus may be important for carbon sequestration. However, field data for quantifying carbonate accumulation have been lacking. This study aims to improve our understanding of SIC dynamics and its role in carbon sequestration. We analyzed two datasets of SOC and SIC and their (13)C compositions , one with over 100 soil sampl...