Types of Magma
1.Felsic magma is the sort that’s rich in feldspar and silica (quartz). As opposed to mafic magma, which is rich in magnesium and iron (Fe to chemists). Felsic magma used to be called ‘acid’. It is pale grey or pinky-grey in color. It derives from a melt of continental (rather than oceanic) crust.
2.Intermediate magma most commonly transforms into andesite due to the transfer of heat at convergent plate boundaries. Andesitic rocks are often found at continental volcanic arcs, such as the Andes Mountains in South America, after which they are named. Felsic Magma.
3.Mafic describes a silicate mineral or igneous rock that has a chemical makeup that is rich in magnesium and iron. Mafic rocks and minerals are usually dark in color. Mafic magma has a low viscosity and mafic eruptions tend to be less violent due to the ability of water and other volatiles to escape more easily. Mar 24, 2017
4.Ultramafic (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally ;18% Mg O, high Fe O, low potassium, and are composed of usually greater than 90% mafic minerals (dark colored, high magnesium and … Ultramafic are igneous and meta-igneous rocks with a very low silica content (less than 45%), …Ultramafic magmas in the Phanerozoic are rarer, and there are very few recognized true ultramafic lavas in the Phanerozoic. Many surface … Containing mainly mafic minerals. Used of igneous rocks and often used interchangeably with ultrabasic. Dunite is an ultramafic rock.
1.Stress causes rocks to deform, meaning the rocks change size or shape. There are different kinds of stress that rocks experience, and these determine how the rocks deform. Tensional stress is when rock is stretched apart. … Compressional stress is when rock is pressed together.
Lithostatic Stress:Overburden pressure, also called lithostatic pressure, confining pressure or vertical stress, is the pressure or stress imposed on a layer of soil or rock by the weight of overlying material.
Stress is the force applied to a rock, which may cause deformation. The three main types of stress go along with the three types of plate boundaries: compression is common at convergent boundaries, tension at divergent boundaries, and shear at transform boundaries.