How are extrusive and intrusive rocks formed
Answers
Answer:
Extrusive rocks are formed on the surface of the Earth from lava, which is magma that has emerged from underground. Intrusive rocks are formed from magma that cools and solidifies within the crust of the planet. ... If lava cools almost instantly, the rocks that form are glassy with no individual crystals, like obsidian.
Answer:
What is the difference between Intrusive and Extrusive Rocks?
Intrusive rocks are formed from magma whereas extrusive rocks are formed from lava.
Intrusive rocks are formed deep inside the surface of the earth whereas extrusive rocks are formed at the surface of the earth when magma finds a way to eject or ...
Cooling and solidification of intrusive rocks takes place very slowly whereas contact with air and water causes cooling of extrusive rocks to take place at a very rapid rate.
Intrusive rock
Intrusive rock is formed when magma penetrates existing rock, crystallizes, and solidifies underground to form intrusions, for example plutons, batholiths, dikes, sills, laccoliths, and volcanic necks. Some geologists use the term plutonic rock synonymously with intrusive rock but other geologists subdivide intrusive rock, by crystal size, into coarse-grained plutonic rock (typically formed deeper in the Earth's crust in batholiths and other plutons) and medium-grained subvolcanic or hypabyssal rock (typically formed higher in the crust in dikes and sills).
The igneous rocks formed due to cooling and solidification of hot and molten lavas at the earth’s surface are called extrusive igneous rocks. Generally, extrusive igneous rocks are formed during fissure eruption of volcanoes resulting into flood basalts. These rocks are also called as volcanic rocks.