Question

Which one out of these is a Plutonic Rock?
1. Gypsum
2. Gneiss
3. Basalt
4. Granite

Answer 1

Correct Answer - Option 4 : Granite

The correct answer is Granite.

• Igneous rocks are the most basic type of rocks. They are formed when magma (molten rock, typically derived from the earth's mantle) solidifies.
• This can happen beneath or above the surface, resulting in 2 subtypes:
  • Plutonic rocks
  • Volcanic rocks
• Plutonic rocks: 
  • When magma never reaches the surface and cools to form intrusions (dykes, sills, etc) the resulting rocks are called plutonic.
  • Granite is an example of Plutonic rock.
• Volcanic rocks: 
  • When magma does reach the surface during a volcanic eruption, the rocks that form there are called lavas or volcanic rocks.
• Sedimentary rocks: 
  • Rocks that are formed by the consolidation of sediments of Pre-existing rocks under the mechanical, chemical, or organic activities of the wind, running water, etc are sedimentary rocks.
• Metamorphic rocks: 
  • Rocks that are formed under the influence of heat, pressure or both from pre-existing rocks are called Metamorphic rocks.