What is a cumulate rock?

A cumulate rock is defined as a type of igneous rock that forms from the accumulation of minerals that crystallize from magma. When magma cools and begins to crystallize, heavier minerals may begin to settle out of the liquid and accumulate at the bottom of the magma chamber. This process is known as magmatic differentiation. As these minerals accumulate, they form a cumulate rock, which is characterized by its distinct layering and mineral composition reflecting the original magma's composition and the temperature and pressure conditions during crystallization.

The formation of cumulate rocks is particularly significant in understanding the geological history and the processes that occur within the Earth’s crust. Since they originate directly from the crystallization of magma, they offer insights into the conditions under which the magma evolved and solidified.