Ocean basins
Four ocean basins on earth at present
- Atlantic, Pacific, Indian, & Arctic
Find a relatively restricted suite of rock types on ocean floors
- Unconsolidated sediments
- Fine-grained sedimentary rocks (clays, oozes, etc.)
- Extrusive igneous rocks of a particular chemical composition - basalts
- Intrusive igneous rocks of the same particular chemical composition - gabbros
- All are underlain by serpentinized peridotites, which are part of the earth�s mantle