What is the difference between mafic and ultramafic rocks

Basalt is a well-known example of a mafic rock. Felsic is the term used for the rocks rich in the mental feldspar , that contains aluminium and silica at high levels. These rocks are also rich in other minerals like oxygen, potassium and sodium. This is the main reason for the low density of felsic rocks.

They are mostly found in specific geographic areas known as convergent zones, where the geologic plates collide. The location has high levels of silica along with water and burnt earth due to the magma , thus making the lava sticky.

Graphite is a well-known example of felsic rocks. Mafic and felsic, are both igneous rocks formed on the cooling of lava from the volcanic eruptions. Igneous rocks, characterized by their silica content can be put in two categories: mafic and felsic other two categories being ultramafic and intermediate.

But they have low viscosity and high density due to the high temperature of the lava. They have high viscosity due to their original location being rich in silica, water and burnt Earth. The low density and light-weight, ascribable to the presence of light-weight minerals such as oxygen, sodium and potassium. Mafic rocks are rich in the heavy minerals, iron and magnesium. This gives these rocks their characteristic dark green or greenish-black colour. Whereas, felsic rocks are rich in silica and aluminium along with oxygen, sodium and potassium that gives the light shade for these rocks.

Skip to content Mafic and felsic are not commonly used terms, as one may observe. Comparison Table Between Mafic and Felsic. What is Mafic? What is Felsic? Main Differences Between Mafic and Felsic The characteristic difference between mafic and felsic is the silica content present in the two rocks. Mafic has low levels of silica. On the other hand, Felsic has much higher levels of silica.

The lavas that are cooled to form these rocks are also different, in terms of their viscosity. The mafic lava usually has a low viscosity and is running. This is per the fact that these lavas erupt at a high temperature. Whereas, felsic rocks have high viscosity. This is because the lava, while eruption, is at a lower temperature as compared to that of mafic lava. Although, the two are igneous rocks, which are defined by their levels of silica, the difference in the silica content in the two rocks, is its origin.

Neither can I! You're absolutely right - the question SHOULD be easy to answer, but a preliminary check has failed to come up with any hard numbers. So, in the absence of scientific fact, we'll have to rely on logic and common sense a fairly uncommon commodity in my house - how about yours? This is actually a pretty rare occurrence , and would lead us to believe that mafic and ultramafic rocks should be fairly uncommon.

A special note concerning ultramafic materials is in order.