Topography of Massive Igneous Rocks
Mantle
- Deep underground layer.
- Composed of liquid rock, known as molten magma.
- Magma can rise to the Earth's surface, forming volcanoes.
- Located approximately 6,900 kilometers underground.
- Brown and yellow horizontal layers.
- Referred to as strata.
Igneous Intrusion
- Solid rock formed underground from magma.
Batholith
- Largest and deepest igneous intrusion.
- Forms when magma solidifies deep underground as it attempts to rise to the surface.
- Consists mainly of granite rock.
Laccolith
- Mushroom or dome-shaped igneous intrusion.
- Formation: Overlying strata (layers of sedimentary rock above the magma) is pushed upwards by the hot magma as it rises.
Lopolith
- Saucer-shaped landform.
- Formation: Underlying strata sinks due to the weight of the magma.
- The heavy magma causes the layers of rock below it to sink, creating a saucer shape which the magma fills.
Dike
- Vertical igneous intrusion.
- Forms when magma solidifies vertically.
Seal
- Horizontal igneous intrusion.
- Forms when magma solidifies horizontally.
Identifying Igneous Intrusions
- Laccolith: Mushroom shape with pushed-up sedimentary rock layers.
- Dike: Vertical, slanted intrusion.
- Batholith: Largest, deepest intrusion.
- Seal: Horizontal shape.
- Lopolith: Saucer shape.
Volcanic Pipe
- Magma reaching the Earth's surface forms a volcano.
- Volcanic pipe: the path where magma rises out of the earth's surface.
- Tors
- Granite domes
- Monoliths