At subduction zones, crustal material is recycled back into the mantle. A certain proportion, however, is returned to the overriding plate via magmatism. The magmas show a characteristic range of compositions that have been explained by three-component mixing in their source regions: hydrous fluids derived from subducted altered oceanic crust and components derived from the thin sedimentary ven...

Applying the pulsed field-gradient nuclear magnetic resonance (PFG-NMR) technique, timedependent self-diffusion coefficients, ) (∆ D 0 D , of water were measured in anhydrite cemented sandstones, in order to determine geometrical parameters of the pore space. As a first approach the Padé approximation, combining the short-time behaviour with the long-time asymptotic value of (where is the bulk ...

Sedimentary Copper mineralization has been observed in Monj and Jolany locations in Bavanat (Sanandaj – Sirjan metamorphic belt). According to current study, the host rocks for copper mineralization in this area are green sandstones, generally in subarkose and arkose groups. Age of these sandstones is middle Jurassic. Copper mineralization is observed in two forms, sulfides form including chalc...

Polycyclic aromatic hydrocarbons in three sections of a dated sediment core from Buzzards Bay, Massachusetts, have been analyzed by gas chromatographic spectrometry. This historical information suggests that sedimentary polycyclic aromatic hydrocarbons, at least at this location, result primarily from the anthropogenic combustion of fossil fuels.

Abrupt disappearance of mass-independent fractionation of sulfur isotopes (MIF-S) from the geologic record and an apparent ingrowth in seawater sulfate around 2.45 billion years ago (Ga) signal the first large-scale oxygenation of the atmosphere [the Great Oxygenation Event (GOE)]. Pre-GOE O2 production is evident from multiple other terrestrial and marine proxies, but oceanic O2 concentrations...

The 13(2),17(3)-cyclopheophorbide a enol (CPP) is shown to convert mainly to a approximately 1:1 mixture of (13(2)R/S) chlorophyllones a (Chlone), when chromatographed over silica gel or alumina supports. 15(1)-hydroxychlorophyllonelactone a and some other chlorophyll a related compounds are also tentatively identified as minor transformation products of CPP. This raises the possibility that th...

Groundwater flow in sedimentary rock saprolite, and in soils derived from this material, is strongly influenced by sedimentary layering and fractures inherited from the parent bedrock. The main objectives of this study were to determine whether parent bedrock lithology and infilling of fractures and other macropores with pedogenically derived clays and Fe/Mn oxides also play major roles in cont...