Extrusive igneous, or volcanic, rocks are formed when magma flows to the Earth's surface and erupts or flows over the Earth's surface in the form of lava; and then it cools and forms the rocks.
Explanation:
Intrusive rocks are those that are formed from a slow cooling, at great depth and in large masses of magma.
The word magma comes from a word of Greek origin that could be translated as ‘pasta’. Volcanic magma is a combination of molten rock and solid and volatile compounds that form inside the Earth. This substance is very unstable and may also contain gas bubbles and suspended crystals. Magma can be easily found in the chambers of a volcano, but also in nearby rocks. Once the magma cools and crystallizes it gives rise to igneous rocks.
Lava and magma are viscous materials from inside the Earth; they are formed of molten rock that originates in the mantle and the core of the planet. The difference between lava and magma is its location relative to the surface of the earth. Magma is found in the inner part of the Earth and lava outside.
Metamorphic rocks (from the Greek meta, change, and morphe, shape, "change of shape") result from the transformation of pre-existing rocks that have undergone structural and mineralogical adjustments under certain physical or chemical conditions, or a combination of both, such as the temperature, the pressure and / or the chemical activity of the fluids agents of the metamorphism These adjustments, commonly imposed below the surface, transform the original rock without losing its solid state generating a metamorphic rock. The rock generated depends on the composition and texture of the original rock, the agents of metamorphism, as well as the time when the original rock was subjected to the effects of the so-called metamorphic process. Due to the nature of their origin, there may be a complete gradation between metamorphic rocks and igneous or sedimentary rocks from which they were formed. The study of these rocks provides very valuable information about geological processes that occurred within the Earth and their variation over time.
Igneous rocks are formed by the cooling and solidification of molten rock matter, magma. Depending on the conditions under which magma cools, the resulting rocks may have coarse or fine granules. Â Igneous rocks are subdivided into two large groups: plutonic and volcanic.
As we explained above, sedimentary rocks (from Latin sedimentum, settlement) are formed by the precipitation and accumulation of mineral matter from a solution or by the compaction of plant and / or animal remains that are consolidated into hard rocks. The sediments are deposited, one layer on the other, on the surface of the lithosphere at relatively low temperatures and pressures and can be composed of pre-existing rock fragments of different sizes, resistant minerals, remains of organisms and products of chemical reactions or evaporation .
Rocks are masses that are made up of the combination between one or more minerals. A mineral is simply a natural substance that is normally solid and inorganic. The rocks do not have a defined chemical composition, because they turn out to be an aggregate of minerals and not minerals.
Mafic rocks are basalt, andesitic and gabro
