sentence: Igneous rocks have a volcanic origin.
sentences_before: Sedimentary rocks may be found anywhere on Earth. When sedimentary rocks are heated and squeezed, they become metamorphic rocks.
sentences_after: Over a very long time, rocks get recycled, in two ways. When marine sediments are raised above sea level, they get weathered, and the pieces carried down to the sea. On a much longer time-scale continental plates may collide.
concept_name: igneous rock
headings: Sedimentary rock Types of sedimentary rock
categories: Sedimentology