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)
“The sun, the hero of every day, the impersonal old man that beams as brightly on death as on birth, came up every morning and raced across the blue dome and dipped into the sea of fire every evening. Water ran down hill and birds nested.”
—Zora Neale Hurston (1891–1960)