Unit Test Flashcards
Are continents in constant motion?
Yes because of tectonic plates moving due to convection currents
What scientist created the continental drift theory and when
Alfred Wegener in 1915
Why didn’t people believe Alfred’s theory back then?
He couldn’t explain what force caused the continents to drift apart
What was Alfred’s four proofs for his theory
- The jigsaw fit between South America and Africa
- They found fossils of the same plants and animals on continents that were once joined (now drifted apart)
- Mountain chains on the east coast of North America and the west coast of Europe match up geologically, having the same age and structure
- Over 250 million years ago continental ice sheets covered the southern parts of India, South America, Africa, and Australia
Explain Plate Tectonics theory
Plates of igneous rocks that sit on magma and float from convection currents
Who and when developed the plate tectonics theory
In 1968 by J. Tuzo Wilson
How many plates?
20
How many major plates? Name them all
8
North American, South American, Pacific, Nazca, African, Eurasian, Australian-Indian, Antarctic
Definition of erosion
Wearing away of Earth’s surface followed by the movement to other locations of materials that have worn away
Define plateau
Elevated flat area
Define differential erosion
Process whereby softer sedimentary rocks erode more quickly than harder rock, shaping the surface of the landscape
Define escarpment
Steep cliff formed by erosion or faulting
Define era
Major devision of geological time
How old is the Earth
4,600,000,000
3 types of mountain building and their definitions
Folding- the bending of rock layers
Faulting- movement along a crack or cracks in the earth’s crust
Volcanism: intrusive- intrusion of igneous mass
extrusive- gases, ashes, and cinders which are ejected from the crater
