12 terms

geoscience - chapter 17 words

Continental Drift
Continents have moved over Earth's surface throughout earth's history
Continents that once formed part of a single landmass.
Sound navigation and ranging. Uses sound waves to measure water depth.
Detects small changes in magnetic fields; measures magnetic field strength.
A narrow, elongated depression in the seafloor with steep sides.
Basaltic lava cools, iron-bearing minerals become oriented parallel to Earth's magnetic field.
Seafloor Spreading
Harry Hess' theory stating that molten rock wells from the mid-ocean ridge valley as the ocean floor moves away from the ridge.
Plate Tectonics
Earth's crust and rigid upper mantle are broken into enormous slabs.
Divergent Boundaries
Plates move away from each other.
Convergent Boundaries
Plates move toward each other.
Transform Boundaries
Plates slide past one another
Mantle convection
Movement of warmer material toward the surface as cooler material sinks deep into the mantle.