In volcanology, a lava dome is a roughly circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. The geochemistry of lava domes can vary from basalt to rhyolite although most preserved domes tend to have high silica content. The characteristic dome shape is attributed to high viscosity that prevents the lava from flowing very far. This high viscosity can be obtained in two ways: by high levels of silica in the magma, or by degassing of fluid magma. Since viscous basaltic and andesitic domes weather fast and easily break apart by further input of fluid lava, most of the preserved domes have high silica content and consists of rhyolite or dacite.
Read more about Lava Dome: Dome Dynamics, Examples of Lava Domes
Famous quotes containing the words lava and/or dome:
“We walk on molten lava on which the claw of a fly or the fall of a hair makes its impression, which being received, the mass hardens to flint and retains every impression forevermore.”
—Ralph Waldo Emerson (1803–1882)
“Thus to him, to this school-boy under the bending dome of day, is suggested, that he and it proceed from one root; one is leaf and one is flower; relation, sympathy, stirring in every vein. And what is that Root? Is not that the soul of his soul?—A thought too bold,—a dream too wild.”
—Ralph Waldo Emerson (1803–1882)