Key Terms Flashcards
Define plate tectonics
Theory that states that the earths outer shell consists of plates that move causing earthquakes, volcanoes, mountains and the formation of new crust
Define geologic history
History of the earths surface from it’s formation to the present day. Divided into periods, called eras
Define convection currents
Circular movements in a gas or liquid created by uneven heating
Define Rift Valley
Valley of land created when two faults drop down
Define moraine
Glacial till left behind after a glacier melts. Found at the end or sides of glaciers.
Define Era
Major divisions of geologic time Pre Cambrian Palaeozoic Mesozoic Cenozoic
Define weathering
Break down of rock into small particles
Define folding
The process of the bending of rock layers due to geologic stresses due to plate movement.
Define faulting
A crack in the earths crust
Subduction zone
When a continental plate collides with an oceanic plate. Earthquakes or folded mountains can form.
Define glacial till
Debris carried by glacial ice
What is the continental drift theory
- Alfred wegener
- 300 M yrs ago
- all of present day continents were constantly moving and crashed forming one supercontinent
- Pangea
- 200 M yrs ago Pangea broke apart which is now the current day continents
Define erosion
Wearing away of earths surface followed by the movement to other locations of materials
Define escarpment
Steep cliff formed by erosion or faulting
Define Straitions
Occurs in rock
Marks and gauges are left on rocks carried by glaciers
