How does an igneous rock cool down rapidly?

Answer 1

One of the most common events that causes the rapid cooling of an igneous rock is its collision with a water-based object. This is included but not limited to bodies of water, icebergs, and snow. The rapid cooling causes air bubbles to be trapped within the rapidly hardening rock, thus resulting in a far less dense geological structure. Certain types of igneous rock, such as pumice, have so much air trapped it that it is less dense than water, enabling it to float.

Answer 2

An igneous rock can cool down rapidly if it comes into contact with water or air at the Earth's surface, which causes the rapid loss of heat from the molten rock and speeds up the solidification process. This quick cooling typically results in the formation of small mineral grains in the rock, known as fine-grained or aphanitic texture.