Intrusive rock
Videos
Intrusive rock is formed when magma penetrates existing rock, crystallizes, and solidifies underground to form intrusions, such as batholiths, dikes, sills, laccoliths, and volcanic necks.
Devils Tower, United States, an igneous intrusion exposed when the surrounding softer rock eroded away
An intrusion (pink Notch Peak monzonite) inter-fingers (partly as a dike) with highly metamorphosed black-and-white-striped host rock (Cambrian carbonate rocks) near Notch Peak, House Range, Utah, United States
Dark dikes intruded into the country rock, Baranof Island, Alaska, United States
Igneous rock
Videos
Igneous rock, or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava.
Intrusive rock
…and solidifies underground to form intrusions, such as batholiths, dikes, sills, laccoliths, and volcanic necks. Intrusion is one of the two ways igneous rock can form. The other is extrusion, such as a volcanic eruption or similar event. An intrusion is any body of intrusive igneous rock, formed from magma…
Volcanic eruptions of lava are major sources of igneous rocks. (Mayon volcano in the Philippines, erupting in 2009)
Natural columns of igneous rock separated from each other by columnar joints, in Madeira
Formation of igneous rock
Extrusive igneous rock is made from lava released by volcanoes