Viscosity of mafic magmas at high pressures

Ultralow viscosity of carbonate melts at high pressures.

Knowledge of the occurrence and mobility of carbonate-rich melts in the Earth's mantle is important for understanding the deep carbon cycle and related geochemical and geophysical processes. However, our understanding of the mobility of carbonate-rich melts remains poor. Here we report viscosities of carbonate melts up to 6.2 GPa using a newly developed technique of ultrafast synchrotron X-ray ...

Adsorption at High Pressures

In Situ Falling Sphere Measurements of the Viscosity of Silicate Melts at High Pressures

Introduction Experimental measurements of viscosity are critical to understanding igneous processes in the Earth’s mantle that control the rate of extraction of melts from partially molten source regions and the time scales for magma mixing. Traditionally, the settling velocity of a highdensity sphere through a molten sample is determined from the initial and final positions of the sphere and e...

Transition between fragmentation and permeable outgassing of low viscosity magmas

Explosive volcanic eruption requires that magma fragments into discrete parcels. Silicic magma can fragment through brittle failure or other processes that depend on the viscoelasticity of the melt. Owing to the low viscosity of basaltic magmas, however, the fragmentation mechanism must be different and will be governed by fluid mechanics alone. We perform a series of decompression experiments ...

HIGH-TEMPERATURE STABILITY OF LAURITE AND Ru–Os–Ir ALLOY AND THEIR ROLE IN PGE FRACTIONATION IN MAFIC MAGMAS: ERRATUM

As a result of an error in the JANAF tables in the free energy of formation (Gf) of the gas species S2O, H2S2 and HS (V. Kress, pers. commun., 2001), calculated values of oxygen and sulfur fugacities, f(O2) and f(S2), respectively, presented in Table 1 of Brenan & Andrews (2001; hereafter BA) are incorrect. A revised version of the program COHSmix was kindly supplied by Victor Kress, and new va...