Apparently, magma from depth is replacing the amount being erupted at a balanced rate.
Some of the thickened crust is due to the intrusion of magma from the mantle, and some to crustal shortening.
New lithosphere is created at oceanic ridges by the upwelling and cooling of magma from the Earth's mantle.
They discovered volcanic rocks from Vanuatu contained tiny crystals of zircon, carried up in magma from the depths by the volcanic plumbing systems.
The magma from Vesuvius, an explosive volcano outside the Ring of Fire, lost its water when the bubbles burst during the Pompeii eruption.
Many people picture a volcano's innards as a vertical tube like a straw drawing magma from a balloonlike well of magma, which obligingly burbles out through a crater.
Here, incandescent magma from the mantle meets cold seawater, and metallic brines gush forth from the rock chimneys known as black smokers.
A mineral such as chromite, with a density considerably greater than the magma from which it crystallizes, will tend to sink as soon as it forms.
If today's weather can bring forth earthquakes and magma from the Earth's crust, it doesn't take much to imagine how the solid Earth is likely to respond to the large-scale environmental adjustments that accompany rapid climate change.
For volcanic eruptions, geologists are moving toward predictive capabilities, but face the challenge of developing a clear picture of the movement of magma, from its sources in the upper mantle, through Earth's crust, to the surface where it erupts.
The whole south coast of Iceland is still being changed — in a decade, in the twinkling of an eye — by volcanic eruptions that pour red-hot magma from mountain ridges, or spout up, boiling from under the thick-ribbed ice.
