The Continents

Continents
Flat features that average 0.8 km (0.5 mi) in elevation
Granitic rocks

Ocean basins
Average 3.8 km (2.8 mi) below sea level
Basalitic rocks

Mountain Belts
Principally the circum-Pacific belt and the Alps/Himalayas

Stable Interior
Shields – expansive, flat regions of deformed crystalline rock
Stable platforms – deformed rocks covered by sedimentary rocks.

Continental Margins

Portions of seafloor adjacent to major landmasses
Includes:
Continental shelf – gently sloping platform extending seaward from shore
Continental slope – steep drop off at edge of continental shelf
Continental rise – more gradual incline; continental slope merges with thick accumulation of sediments

Deep-Ocean Basins
Between continental margins and oceanic ridges
Abyssal plains – flat features of deep-ocean basins
Deep-ocean trenches – deep depressions in ocean floor
Seamounts – submerged volcanic structures

Oceanic Ridge
Also called mid-ocean ridge
Includes Mid-Atlantic Ridge and East Pacific Rise
Continuous mountain belt that winds around globe
Many layers of igneous rock

Earth is a dynamic body with many separate but highly interacting parts or spheres
Earth system science studies Earth as a system composed of numerous parts, or subsystems
System – any size group of interacting parts that form a complex whole

System
Closed systems are self-contained (e.g., an automobile cooling system)
Open systems – both energy and matter flow into and out of the system (e.g., a river system)

Earth as a system
Consists of a nearly endless array of subsystems (e.g., hydrologic cycle, rock cycle)

Earth as a system
Sources of energy
Sun – drives external processes such as weather, ocean circulation, and erosional processes
Earth’s interior – drives internal processes including volcanoes, earthquakes, and mountain building
Humans are part of the Earth system