Question

Place the following events in sequence:

A) Mineral grains are formed
B) A volcano erupts
C) Lava begins cooling

Answer 1

The sequence of events after a volcanic eruption related to the formation of igneous rocks is: first, the volcano erupts, followed by lava cooling on the earth's surface, and finally, the formation of mineral grains as the lava solidifies into igneous rock.

Step-by-step explanation:

To correctly place the events in sequence related to the formation of igneous rocks due to volcanic activity, we must understand the processes involved:

1. B) A volcano erupts: This is the initial stage where magma is expelled from the earth's interior.
2. C) Lava begins cooling: After the eruption, lava flows onto the surface and starts to lose heat to the surrounding environment.
3. A) Mineral grains are formed: As the lava cools, the rates of cooling affect the crystal size of the minerals that form, eventually resulting in solidified igneous rock.

It is important to note that a basaltic eruption produces lava that moves quickly and can cover large distances. Once lava is exposed at the surface, it cools at a faster rate compared to magma that cools slowly beneath the earth's surface, leading to small-grained minerals. In contrast, slow cooling allows for the growth of large mineral grains, creating coarse-grained rocks known as intrusive or plutonic rocks. Therefore, the sequence of events for the creation of igneous rocks after a volcanic eruption is volcano eruption, lava cooling, and then mineral grain formation.