GEOCHEMISTRY: Charting Sorption Variations

Geochemistry of Uranium at Mineral-water Interfaces: Rates of Sorption-desorption and Dissolution-precipitation Reactions

Seasonal variations in pore water and sediment geochemistry of littoral lake sediments (Asylum Lake, MI, USA)

BACKGROUND Seasonal changes in pore water and sediment redox geochemistry have been observed in many near-surface sediments. Such changes have the potential to strongly influence trace metal distribution and thus create seasonal fluctuations in metal mobility and bioavailability. RESULTS Seasonal trends in pore water and sediment geochemistry are assessed in the upper 50 cm of littoral kettle...

Isotope Geochemistry

Isotopic analysis can be performed on minerals, rocks, soil, tissue, gases, and liquids – just about anything. In view of the broad possibilities, we will only cover a few generalities here. In most instances, the element to be analyzed must be first isolated and purified before it can undergo isotopic analysis in a mass spectrometer. Purification is necessary to avoid isobaric interferences an...

Regional and local variations in geochemistry and tectonics along and across Central America

Three tectono-magmatic systems create volcanism in Central America; the volcanic front, a weak secondary front and the back-arc. Most magma output occurs at the volcanic front along narrow lines of historically active composite volcanoes in strikeslip/extensional settings. Lavas have strong slab signature, are water-rich and plagioclase and pyroxene phyric. A sporadic secondary front occurs abo...

Charting Recent Progress

Congress on Alcohol and Health is updated and submitted to Congress by the Secretary of Health and Human Services (HHS) every 3 years. This important document summarizes recent advances in alcohol research and charts current progress toward preventing and decreasing alcohol abuse and alcoholism. As well as being submitted to Congress, the report is distributed throughout the country to research...