I prepared compilations of geochemical data from the central part of the Mexican Volcanic Belt (C-MVB), the Central American Volcanic Arc (CAVA) from Guatemala to northwestern Costa Rica, the continental arc of the Andes in South America, other mostly island arcs, extensional and continental break-up regions, and continental rifts. Using quantitative statistical methods, the origin of the C-MVB...

Natural, dissolved (238)U-series radionuclides (U, (226)Ra, (222)Rn) and activity ratios (A.R.s: (234)U/(238)U; (228)Ra/(226)Ra) in Continental Intercalaire (CI) groundwaters and limited samples from the overlying Complexe Terminal (CT) aquifers of Algeria and Tunisia are discussed alongside core measurements for U/Th (and K) in the contexts of radiological water quality, geochemical controls i...

The microbial community in eutrophic freshwater sediment was investigated from a 67-cm-deep sediment core collected from the Daechung Reservoir in South Korea, where cyanobacterial blooms have occurred annually for the past 30 years. The majority of core sediments were characterized by dark-grayish, fine-grained mud with abundant gas-escaped and thinly laminated layers. Intervals of summer and ...

Article history: Received 29 March 2017 Accepted 27 July 2017 Available online 04 August 2017 Subduction and collision are the key processes triggering geochemical refertilization of the lithospheric mantle beneath cratons. However, the way that the subducted plate influences the cratonic lithospheric mantle remains unclear. Here, in-situ major and trace-element and Sr isotopic compositions of ...

In June 2007 sediment cores were collected in Alaminos Canyon, Gulf of Mexico across a series of seismic data profiles indicating rapid transitions between the presence of methane hydrates and vertical gas flux. Vertical profiles of dissolved sulfate, chloride, calcium, magnesium, and dissolved inorganic carbon (DIC) concentrations in porewaters, headspace methane, and solid phase carbonate con...

Multicomponent contaminant transport models in groundwater are typically based on assumptions of local geochemical equilibrium on the grid scale. In heterogenous systems there may be significant coupling between transport processes and geochemical equilibrium at smaller than grid block scale. When these processes are upscaled to grid scale, geochemical evolution may take on a kinetic character....

Despite a number of studies in areas of focused methane seepage, the extent of transitional sediments of more diffuse methane seepage, and their influence upon biological communities is poorly understood. We investigated an area of reducing sediments with elevated levels of methane on the South Georgia margin around 250 m depth and report data from a series of geochemical and biological analyse...

Synopsis Newly-acquired regional geochemical data for the Down-Armagh (Northern Ireland) sector of the Southern Uplands – Down-Longford terrane are assessed by comparison with the equivalent dataset for southern Scotland. Despite the much thicker glacigenic cover to the Down-Armagh bedrock, the principal geochemical lineaments identified in the Southern Uplands are still apparent. Patterns of e...

Geochemical study of a 3.55 m long lake sediment core from the Badanital Lake (Garhwal Himalaya) reveals Late Holocene centennial-scale climatic changes. The ecosystem of the tectonically formed lake seems to be controlled by natural and anthropogenic factors. The imprints of four major global events, e.g. 4.2 ka event, Medieval Warm Period (MWP), Little Ice Age (LIA) and modern warming are obs...

Meyers, P.A., 1993. Origin of the Plio-Pleistocene Vrica laminites: Organic geochemical evidence. Mar. Geol., 115: 117-127. Organic geochemical properties of samples from lower Pleistocene laminite Layer H at Vrica, Calabria, have been examined for evidence of the origin of these dark-colored sediments. The laminite samples are geochemically distinct from the surrounding gray marly clays. They ...