Oceanography Ch. 3 Flashcards
Alfred Wegener
A busy German meteorologist and polar explorer
Continental Drift
Theory that Earth was once a supercontinent
Pangaea
Super continent Earth
Panthalassa
Pangaea’s surrounding oean
Density
An expression of the relative heaviness of a substance
Earthquakes
Shaking of Earth’s crust due to tectonic plate movement
Seismic Waves
Low-frequency waves generated by earthquakes
Surface Waves
Move along Earth’s surface
Body Waves
Useful for analyzing Earth’s interior structure
P Wave
Compressional wave similar to a sound wave
S Wave
Shear wave like a rope shaken side to side
Seismograph
An instrument that senses and records earthquakes
Shadow Zone
A wide band from which S waves were absent
Crust
Lightweight, brittle, uppermost layer of Earth
Oceanic Crust
Primarily basalt, a heavy dark-colored rock
Continental Crust
Primarily granite, speckled rock
Mantle
The layer beneath the crust
Lithosphere
Earth’s cool, rigid, outer layer 70-200 km in thickness
Asthenosphere
The hot, partially melted, slowly flowing layer of upper mantle below the lithosphere
Lower Mantle
Extends to the core
Core
Consists of two parts; dense, viscous outer core, solid inner core
Radioactive Decay
An important form of heat formed from separating nuclei
Conduction
Heat rising to Earth’s surface
Convection
When fluid or semisolid is heated and rises
Buoyancy
Ability of an object to float in a fluid
Isostatic Equilibrium
When volume displaced by object is equal to weight of displaced object
Fault
A plane of weakness
Uniformitarianism
Theory that Earth’s geological features could be explained by present-day processes
