Geochemistry: Ocean islands — plums or plumes?

Bats of the Western Indian Ocean Islands

The natural colonisation of many remote oceanic islands by bats, including those of the western Indian Ocean, has been facilitated by their unique capability among mammals for powered flight. In the western Indian Ocean region, only the Malagasy islands of Madagascar and the Comoros archipelago have been naturally colonised by non-volant mammals. Despite their greater potential for inter-island...

CO fluxes from mid - ocean ridges , arcs and plumes 2

Estimates of CO emissions at spreading centres, convergent margins, and plumes have been reviewed and upgraded 2 using observed CO r He ratios in magmatic volatiles, He content estimates in the magmatic sources, and magma 2 emplacement rates in the different tectonic settings. The effect of volatile fractionation during magma degassing, Ž . investigated using new rare gas and CO abundances dete...

Deep mantle plumes and convective upwelling beneath the Pacific Ocean

Barite in the ocean – occurrence, geochemistry and palaeoceanographic applications

The mineral barite (BaSO4) can precipitate in a variety of oceanic settings: in the water column, on the sea floor and within marine sediments. The geological setting where barite forms ultimately determines the geochemistry of the precipitated mineral and its usefulness for various applications. Specifically, the isotopic and elemental composition of major and trace elements in barite carry in...

Particle Geochemistry of Volcanic Plumes of Etna and Mount St. Helens

Particles in volcanic plumes forecasting [Rose et al., 1983]. The volcanogenic include vapor condensates and reaction products element fluxes provide a baseline for air of ash with vapors or condensed liquids, in pollution [e.g., Varekamp and Buseck, 1986]. addition to abundant silicate particles. In the In volcanic plumes, tiny particles form as a 1980 M•unt St. Helens plume we detected abunda...