Mafic rocks

Mafic is an adjective describing a silicate mineral or igneous rock that is rich in magnesium and iron, and is thus a portmanteau of magnesium and ferric. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks include basalt, diabase and gabbro. Mafic rock , in geology, igneous rock that is dominated by the silicates pyroxene, amphibole, olivine, and mica.

These minerals are high in magnesium and ferric oxides, and their presence gives mafic rock its characteristic dark colour.

Mafic rock is commonly contrasted with felsic rock, in which light-coloured minerals predominate. What are the elements that make up mafic and felsic rock? What is an example of mafic igneous rock? Are mafic rocks high or low?

Felsic and mafic rocks , division of igneous rocks on the basis of their silica content. Mafic rocks that constitute the igneous oceanic crust are created at mid-ocean ridge seafloor spreading centers as a byproduct of partial melt from upwelling mantle. Through various parts of the spreading process, permeability can be generated in both the intrusive gabbros and extrusive basalts.

While non-geologists may look at a rock and just see a rock, geologists are likely thinking of one of the hundreds of descriptive terms they use to describe rocks.

They have different terminology for describing chemical composition, texture, mineral proportions, and sometimes even location. This lesson is on mafic , which is one of the terms used to describe the chemical comp. See full list on study. Mafic was originally reserved to describe minerals that had a high percentage of iron and magnesium. However, the term is now commonly used to both describe igneous rocks that contain a high percentage of mafic minerals and magmas that will eventually crystallize a high percentage of mafic minerals.

Remember that igneous rocks are those that are formed from cooled magma. From experimental studies of magma and crystal formation, we know that mafic minerals crystallize at higher temperatures than felsic minerals. The more mafic minerals crystallize first, followed by the more felsic minerals. Thus, mafic rocks form at higher temperatures than felsic rocks.

Mafic rocks have between and of silica, whereas felsic rocks have over of silica, the highest of all types. Due to the color of the minerals forming them, the rocks are either light or dark. As iron-rich silicates are normally dark in color, mafic rocks are dark-colored.

Basalt Fiber is made from natural basalt rock. It offers compelling performance, enabling lightweight composites of the future. Mafic customers use basalt products to save weight, improve performance, and remain cost competitive. Ultramafic rocks (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 ), generally MgO, high FeO, low potassium, and are composed of usually greater than mafic minerals (dark colore high magnesium and iron content).

Mafic magmas are usually produced at spreading centers, and represent material which is newly differentiated from the upper mantle.

Low Prices on Volcanic Rocks. Free Shipping on Qualified Orders. In terms of chemistry, mafic rocks are on the other side of the rock spectrum from the so-called felsic rocks.

Mafic lava, before cooling, has a lower viscosity than felsic lava due to its lower silica content. The term roughly corresponds to the older basic rock class. Water and other volatiles can.

Mafic definition, of or relating to rocks rich in dark, ferromagnesian minerals. Mafic rocks Rocks composed mostly of pyroxene, calcium-rich plagioclase, and minor amounts of olivine make up the mafic family of igneous rocks. The mafic magmas are somewhat more viscous than the ultramafic magmas, but they are still fairly fluid.

Metamorphism of Mafic Rocks l Clinopyroxene breaks down to a number of mafic minerals, depending on grade. Mafic rocks are obtained from mostly the sea bed volcanoes whereas felsic rocks are obtained from the cooling of lavas from the convergent zones. Due to their origin, the minerals found in the two rocks are also different. Mafic is rich in heavy minerals like magnesium and ferric, or iron. But Felsic is rich in silica and aluminium.

Diabase dikes and sills are typically shallow intrusive bodies and often exhibit fine grained to aphanitic chilled margins which may contain tachylite (dark mafic glass). In modern usage, the term acid rock , although sometimes used as a synonym, refers to a high-silica-content (greater than SiO by weight) volcanic rock , such as rhyolite. This is in contrast to granitic rocks of the BC, where bulk rock compositions are very close to MIZ compositions, suggesting a highly different magmatic evolution prior to MIZ.