| Sedimentary and metamorphic rocks |
Once the rocks are formed from magma that rises and rises to the surface, can undergo various processes that transform them. On the one hand, they can be pulverized by erosion and its fragments, giving rise to sedimentary rocks. In addition, they can sink - or they come to the surface - and be transformed by heat and pressure, resulting in metamorphic rocks.  Sedimentary rocks Sedimentary rocks are composed of processed materials, formed by the accumulation and consolidation of powdered mineral material, deposited by erosion. Sedimentary rocks are classified according to their origin: Detrital rocks, or fragmentary, are composed of mineral particles produced by the mechanical disintegration of other rocks and transported without chemical deterioration due to water. They are hauled up larger masses of water, where they are deposited in layers. Examples: shale and sandstone. Chemical sedimentary rocks are formed by chemical deposition of materials that have been in solution during its transport. Sedimentation in these processes can also influence the activity of living organisms, in which case one can speak of biochemical or organic origin. Examples: gypsum, anhydrite and limestone.  Metamorphic rocks Metamorphic rocks are those whose original composition and texture have been altered by heat and pressure. This process is called metamorphosis of the rock. Environments with heat and pressure sufficient to cause metamorphism are often found where the Earth's tectonic plates are coming together. There, the plates collide, grind the rocks are heated to greater depths for the magma. The rocks can be altered in small areas of contact metamorphism, or in large areas by the regional metamorphism. The contact metamorphism occurs when magma intrudes cooler rock. Bedrock or in cash (the coldest) forms a zone of alteration contacto.La called halo halo can be divided into zones metamorphic and intrusive that were formed near the high-temperature minerals such as garnet while more far be formed as low-grade mineral chlorite. Regional metamorphism occurs when large regions of the cortex are compressed and distorted. When the rivers accumulated sediment on the rocks in sedimentary basins hundreds of millions of years, pressure is growing on these rocks and the basin is slowly sinking. Over time the temperature and pressure in the lower layers oldest begins to rise to metamorphism. Another form of regional metamorphism occurs where tectonic plates converge. A plate dives beneath the other into the mantle. In these subduction zones occurs magma that rises through the crust, causing metamorphism in large regions of continental crust near subduction zones.
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