A new variation diagram has been devised in which the ratio $\frac{Total O not combined in OH^{-}}{Si^{+4}+ (A1^{+3} in 4-co-ordination)}X10$ is plotted as abscissa. This ratio, here called the ...

Abstract: Field relations in dissected volcanic terrains and the internal evidence of persistent low-pressure cotectic character in erupted basalts point to the frequent and substantial modification ...

It is common for silicate-rich magmas to form at destructive plate boundaries, by partial melting and / or assimilation of crustal rocks (richer in silica than the mantle rock). As basalts or gabbros, ...

Mafic lavas are hot, high in silica, low in volatiles, and relatively viscous. Volcanic lavas are called felsic lavas, and they are usually cooler and include high levels of silica and volatiles.

The world's ocean basins are constantly being regenerated by an 80,000-kilometre-long volcanic system of mid-ocean ridges, where Earth's mantle melts to form magma that eventually produces the ...

Basalts erupted in the Snake River Plain of central Idaho and sampled in the Kimama drill core link eruptive processes to the construction of mafic intrusions over 5.5 Ma. Cyclic variations in basalt ...

This is a preview. Log in through your library . Abstract Boisa Island is the tip of a Quaternary island-arc volcano. It consists of an older cone made up of porphyritic, amphibole-free, mafic rocks, ...

Oceanic crust covers two-thirds of Earth's solid surface, but scientists still don't entirely understand the process by which it is made. Analysis of more than 600 samples of oceanic crust reveals a ...