EARTH SCIENCE
VOLCANOES
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
true
|
|
|
false . The thermal energy below the surface melts the rock and releases fluids from the subducting plate. This forms new magma. Magma is LESS dense than the mantle and rises through cracks in the crust. This forms a volcano.
|
|
|
Either A or B
|
|
|
None of the above
|
Detailed explanation-1: -Scientists use the term magma for molten rock that is underground and lava for molten rock that breaks through the Earth’s surface.
Detailed explanation-2: -Lava Lake. Magma is a molten and semi-molten rock mixture found under the surface of the Earth. On the rare occasions when magma breaks the surface, as in a volcanic eruption, it is called lava.
Detailed explanation-3: -The magma, called lava when molten rock erupts on the surface, cools and solidifies almost instantly when it is exposed to the relatively cool temperature of the atmosphere.
Detailed explanation-4: -When lava reaches the surface of the Earth through volcanoes or through great fissures the rocks that are formed from the lava cooling and hardening are called extrusive igneous rocks. Some of the more common types of extrusive igneous rocks are lava rocks, cinders, pumice, obsidian, and volcanic ash and dust.