Halogens show a range from moderate (F) to highly (Cl, Br, I) volatile and incompatible behavior, which makes them excellent tracers for volatile transport processes in the Earth's mantle. Experimentally determined fluorine and chlorine partitioning data between mantle minerals and silicate melt enable us to estimate Mid Ocean Ridge Basalt (MORB) and Ocean Island Basalt (OIB) source region conc...

Crater size–frequency analyses have shown that the largest volcanic plains deposits on Mercury were emplaced around 3.7 Ga, as determined with recent model production function chronologies for impact crater formation on that planet. To test the hypothesis that all major smooth plains on Mercury were emplaced by about that time, we determined crater size–frequency distributions for the nine next...

The Atlas Mountains of Morocco display high topography, no deep crustal root, and regions of localized Cenozoic alkaline volcanism. Previous seismic imaging and geophysical studies have implied a hot mantle upwelling as the source of the volcanism and high elevation. However, the existence, shape, and physical properties of an associated mantle anomaly are debated. Here we use seismic waveform ...

[1] Helium isotopes are a robust geochemical tracer of a primordial mantle component in hot spot volcanism. The high He/He (up to 35 RA, where RA is the atmospheric He/He ratio of 1.39 10 ) of some Hawaiian Island volcanism is perhaps the classic example. New results for picrites and basalts from the Hawaiian-Emperor seamount chain indicate that the hot spot has produced high He/He lavas for at...

[1] We report Hf isotope compositions of 79 lavas that record the early ( 5–95 Ma) history of the Galápagos plume volcanism. These include lavas from the Caribbean Large Igneous Province (CLIP; 95–70 Ma), the accreted Galápagos paleo-hot spot track terranes (54–65 Ma) of Costa Rica (Quepos, Osa and Burica igneous complexes), and the Galápagos hot spot tracks (<20 Ma) located on the Pacific seaf...

We determined model ages of mare deposits on the farside of the Moon on the basis of the crater frequency distributions in 10-meter-resolution images obtained by the Terrain Camera on SELENE (Selenological and Engineering Explorer) (Kaguya). Most mare volcanism that formed mare deposits on the lunar farside ceased at approximately 3.0 billion years ago, suggesting that mare volcanism on the Moo...

[1] We report Hf isotope compositions of 79 lavas that record the early ( 5–95 Ma) history of the Galápagos plume volcanism. These include lavas from the Caribbean Large Igneous Province (CLIP; 95–70 Ma), the accreted Galápagos paleo-hot spot track terranes (54–65 Ma) of Costa Rica (Quepos, Osa and Burica igneous complexes), and the Galápagos hot spot tracks (<20 Ma) located on the Pacific seaf...

[1] Mars Orbiter Camera images are used to identify widespread material interpreted to have formed via explosive volcanism on Arsia Mons volcano, Mars. This material crops out in cliff sections associated with pit craters in layers 45– 50 m thick. The large range of elevations where the material is found (6.2–17.5 km) suggests locally-derived materials, although extensive reworking has produced...

The possibility of volcanism on Mercury has been a topic of discussion since Mariner 10 returned images of half the planet's surface showing widespread plains material. These plains could be volcanic or lobate crater ejecta. An assessment of the mechanics of the ascent and eruption of magma shows that it is possible to have widespread volcanism, no volcanism on the surface whatsoever, or some r...

New H2O, CO2 and S concentration data for basaltic glasses from ‘hotspot’, with temperature differences of 200°C or more between hotter upwelling plumes and the ambient mantle Loihi seamount, Hawaii, allow us to model degassing, assimilation, adiabat (e.g. White & McKenzie, 1989; Campbell, 1998; and the distribution of major volatiles within and around the Davies, 1998). In contrast, it has lon...