Crystal settling from magma occurs:
A) whenever metal-bearing solutions encounter changing conditions that cause precipitation.
B) when surface streams slow down and deposit sediment.
C) when the lightest crystals rise to the top of a magma chamber.
D) when early formed crystals sink to the bottom of a magma chamber.

Question

Quizplus · Accepted Answer

Crystal settling from magma occurs when early formed crystals have a higher density than the surrounding liquid magma and thus sink to the bottom of a magma chamber. This process can lead to the formation of layered igneous rocks such as gabbro and granite. Options A and B describe different processes of chemical and physical weathering respectively. Option C describes the opposite process of crystal settling, which is called crystal fractionation, where lighter crystals are separated from denser magma and rise to the top.

Crystal Settling from Magma Occurs