A great peak that rises out of the flat, barren desert.
Great example of a natural feature on the Earth’s surface (landform) that is made of igneous rocks.
Ship rock formed about 1 km below the surface of the Earth 30 million years ago. It was once intrusive igneous rock. These types of formations are harder and more lasting than other types of rock. It is now extrusive igneous rock.
The Hawaiian islands are built of basalt lava.
Basalt lava flows long distances.
The volcanoes that formed them started erupting on the sea floor and over a very long time they grew tall enough to rise out of the ocean!
Extrusive formations (cont.)
Mt. Saint Helens (Washington)
This volcano’s lava is silica rich.
This lava builds cone shaped volcanoes with steep sides.
These erupt explosively since the lava is thick, sticky and under high pressure.