Q:

What rock is formed when magma cools at the Earth's surface?

A:

Quick Answer

The specific type of rock that forms when magma cools at the Earth's surface is extrusive igneous rock. Igneous rock forms when magma cools, but where the magma cools determines the type of igneous rock that forms. Igneous rock gets its name from the Greek word for fire and is so called due to the extremely hot liquid from which the rocks originate.

Know More
What rock is formed when magma cools at the Earth's surface?
Credit: Koshy Johnson Oxford Scientific Getty Images

Full Answer

When magma cools at the surface, it cools rapidly and does not have time to form very large crystals. Basalt, found on the ocean floor, is an example of an extrusive igneous rock. On the other hand, magma that cools slowly beneath the Earth's surface forms rocks that contain large crystals. Geologists refer to these as intrusive igneous rocks; granite is an example of an intrusive igneous rock.


Is this answer helpful?

Similar Questions

  • Q:

    How is a plateau formed?

    A:

    A plateau is formed by a process of geological uplift, either due to the collision of continental plates, pressure from magma below or the burial of land by volcanic lava and ash flows, resulting in a high, flat surface. These are very similar to processes that give rise to mountains and mountain ranges. The only major difference is that a plateau is flat while mountains are peaked.

    Full Answer >
    Filed Under:
  • Q:

    How is a laccolith formed?

    A:

    A laccolith is a geological structure that forms when magma pushes through layers of rock above it and pools in a dome shape. Laccoliths are characterized by their shape, as they are typically flat on the bottom and rounded or dome shaped on top. These structures are also called plutonic formations or igneous intrusions, which are related to sills.

    Full Answer >
    Filed Under:
  • Q:

    What is sedimentary rock?

    A:

    Sedimentary rocks are formed by the deposition of mud, clay, sand and other small particles on the surface of the Earth. Sedimentation can occur in many different environments, including lakes, rivers, deserts and oceans. The sediment is deposited in layers that are compressed over time and turned into solid rock.

    Full Answer >
    Filed Under:
  • Q:

    How is metamorphic rock formed?

    A:

    Metamorphic rock is formed underground through a process that changes a rock's molecular structure due to pressure, heat and chemical reactions. A metamorphic rock forms from a parent rock called a protolith. Depending on conditions, a protolith can transform into any metamorphic rock. Because protoliths are capable of undergoing vast changes, identifying them is sometimes difficult for geologists.

    Full Answer >
    Filed Under:

Explore