How do geologists classify rocks?

1 Answer
Jun 10, 2016

By their relationship in the rock cycle and hence, the terms igneous, sedimentary and metamorphic.

Explanation:

Centuries ago geologists classified rocks into the three basic types: igneous (new volcanic rocks), sedimentary (the product of weathering and erosion) and metamorphic (changed rocks due to burial or pressure).

More recently, the theory of plate tectonics and the rock cycle has given new meaning to this classification system as they all slot into different geological settings.

https://rock-water-cycles-atmosphere-diagram.wikispaces.com/Rock+Cyclenter image source here