section of the Earth’s crust![click to hear](/images/speaker.jpg)
The Earth’s crust, continental and oceanic, is composed mainly of sedimentary, metamorphic and igneous rock.
sedimentary rocks ![click to hear](/images/speaker.jpg)
Rocks formed by the accumulation, compaction and cementation of fragments of eroded rock and debris left by living organisms.
granitic layer ![click to hear](/images/speaker.jpg)
Layer of granite that gives the continents their essential form.
basaltic layer ![click to hear](/images/speaker.jpg)
Layer of basalt, a rock denser than granite, that forms the deep-sea floor and is covered with various types of debris.
deep-sea floor ![click to hear](/images/speaker.jpg)
Part of the Earth’s surface beneath the seas and the oceans; its topography is highly variable.
sea level ![click to hear](/images/speaker.jpg)
Average height of seawater observed for a given time (day, month, year); it is used as a reference point to define coastal features and measure land elevations.
intrusive rocks ![click to hear](/images/speaker.jpg)
Igneous rocks that have risen close to the Earth’s surface.
mountain range ![click to hear](/images/speaker.jpg)
A row of elevated connected landforms characterized by high summits and deep valleys.
volcano ![click to hear](/images/speaker.jpg)
Landform built up as lava and ash are ejected from the upper mantle during successive eruptions, accumulating and solidifying on the surface.
igneous rocks ![click to hear](/images/speaker.jpg)
Rock formed from molten magma that has cooled and solidified inside the Earth; also called magmatic rock.