Q. Which among the following is/ are the sources of Magma?

1. Molten Outer Core of the Earth
2. Solid Rocks of Earth Crust
3. Solid Rocks of Mantle

Select the correct option from the codes given below:
Answer: Only 2 & 3
Notes: Only part of the earth that is liquid is the outer core. However, outer core is NOT the source of Magma, because it does not have the right chemical composition. For instance, the outer core is mostly Iron, but magmas are silicate liquids. Magma originates in the lower part of the Earth’s crust and in the upper portion of the mantle. There, high temperatures and pressure cause some rocks to melt and form magma. Since the rest of the earth is solid, in order for magmas to form, some part of the earth must get hot enough to melt the rocks present. Then, magma does not occur everywhere below us. There are only some specific places where volcanoes exist. This means that Magma is formed under some special conditions, which exist in some limited area.

This question is part of UPSC Daily 20 MCQ Series Course on GKToday Android app.