Lady's slipper orchids (Cypripedium spp.) are rare terrestrial plants that grow throughout the temperate Northern Hemisphere. Like all orchids, they require mycorrhizal fungi for germination and seedling nutrition. The nutritional relationships of adult Cypripedium mycorrhizae are unclear; however, Cypripedium distribution may be limited by mycorrhizal specificity, whether this specificity occu...

a r t i c l e i n f o a b s t r a c t Improving the reliability and accuracy in the determination of the depth to velocity discontinuities in the Earth's mantle is essential for a better understanding of mantle dynamics, as well as for addressing such fundamental questions as the origin of mantle plumes and fate of subducted slabs. Most existing techniques that utilize receiver function stackin...

Magma genesis, migration, and eruption have played prominent roles in the chemical differentiation of the Earth. Plate tectonics has provided the framework of tectonic environments for different suites of igneous rocks and the dynamic mechanisms for moving masses of rock into melting regions. Petrology is rooted in geophysics. Petrological and geophysical processes are calibrated by the phase e...

The P-T conditions of both equilibria were determined precisely by reversal experiments in a piston-cylinder apparatus. On the basis of 8 experiments, brackets for the rutile-magnesite-geikielite equilibrium are 7.0–7.1 kbar at 800 ∞C, 8.6–8.7 kbar at 850 ∞C, and 10.5–10.7 kbar at 900 ∞C. On the basis of 9 experiments, brackets for the zircon-magnesite-baddeleyite-forsterite equilibrium are 7.1...

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...

Convergent plate margins are arguably the most complicated and dynamic plate boundaries on Earth and have been the subject of many investigations and discussions since the advent of plate tectonic theory. Due to the varied, heterogeneous and complex structure of convergent plate margins, which arises from the multiple geological, physical and chemical processes operating at these zones, and bec...

Question : Rich fens of the Sphagno warnstorfii-Tomentypnion nitentis alliance require a specific combination base richness and climate to occur. Their rarity at southeastern margins their European range has previously prevented rigorous vegetation classification. We asked how many associations may be delimited here whether some them are restricted high Balkan Mountains showing endemicity. Stud...

We designed and carried out experiments to investigate the effect of H2O on the liquidus temperature of olivine-saturated primitive melts. The effect of H2O was isolated from other influences by experimentally determining the liquidus temperatures of the same melt composition with various amounts of H2O added. Experimental data indicate that the effect of H2O does not depend on pressure or melt...

Boninites are unusual island arc volcanic rocks with high MgO (>9%), high Si0 2 (>55%) contents, and exceptionally low TiO 2 (<0.4%) contents. High MgO contents, MgO/(MgO + EFeO), Ni, Cr and Co contents indicate that boninites have equilibrated with mantle peridotite. Experimental petrologic studies and high Cr/(Cr + Al) in spinels in boninites suggest that they have separated from extremely re...