Magma comes from mantle, 2 to 100 miles down, to surface {volcano}| through crust fissures. Magma then cools and hardens. Most of Earth water vapor and gases came from volcano eruptions.
types
Thick magma has more gas, is red hot, erupts explosively, and makes steep mountains. Thin magma has little gas, is white hot, and makes wide mountains.
examples
Famous volcanoes are Mount Vesuvius in Italy, which buried Pompeii [79]. Krakatoa in Indonesia exploded island [1869]. Mount Etna in Italy caused enormous avalanche and undersea mudslide [-6000] and started a huge tsunami: it is still active. Mauna Loa in Hawaii is active.
Volcanoes can erupt {volcanism} where plates collide, making andesite lava.
Magma can spread to make stock rock masses, which can be thousands of square miles wide {batholith}.
Volcano tops have craters {caldera}|.
Magma can flow into vertical rock fissures and cool and harden {dike, magma}.
Cylindrical columns {kimberlite pipe} from mantle to crust can have 300-meter diameter.
Magma {lava}| can reach surface.
Molten igneous rock {magma}|, mixed with gas and water vapor, comes from mantle, 2 to 100 miles down, to surface through crust fissures.
Magma can make underground pools {sill, magma}.
Magma can spread to make large rock masses {stock, rock}.
5-Earth Science-Planet-Plate Tectonics
Outline of Knowledge Database Home Page
Description of Outline of Knowledge Database
Date Modified: 2022.0225