melted rock (magma) is called lava when it reaches the earth's surface.
melted rock (magma) is called lava when it reaches the earth's surface.
what is melted rock (magma) called when it reaches the earth's surface?
lava
when rocks are pushed deep under the earth's surface, they may melt into magma. if the conditions no longer exist for the magma to stay in its liquid state, it cools and solidifies into an igneous rock. a rock that cools within the earth is called intrusive or plutonic and cools very slowly, producing a coarse-grained texture such as the rock granite. as a result of volcanic activity, magma (which is called lava when it reaches earth's surface) may cool very rapidly while being on the earth's surface exposed to the atmosphere and are called extrusive or volcanic rocks. these rocks are fine-grained and sometimes cool so rapidly that no crystals can form and result in a natural glass, such as obsidian, however the most common fine-grained rock would be known as basalt. any of the three main types of rocks (igneous, sedimentary, and metamorphic rocks) can melt into magma and cool into igneous rocks.
rock cycle
when rocks melt, they do so slowly and gradually because most rocks are made of several minerals, which all have different melting points; moreover, the physical and chemical relationships controlling the melting are complex. as a rock melts, for example, its volume changes. when enough rock is melted, the small globules of melt (generally occurring between mineral grains) link up and soften the rock. under pressure within the earth, as little as a fraction of a percent of partial melting may be sufficient to cause melt to be squeezed from its source. melts can stay in place long enough to melt to 20% or even 35%, but rocks are rarely melted in excess of 50%, because eventually the melted rock mass becomes a crystal-and-melt mush that can then ascend "en masse" as a diapir, which may then cause further decompression melting.
magma