Details

Title: Env. Geo. Chapter 2

Description: Crust and core of earth

Total Flash Cards: 5

Created: 02/26/2006 13:06:29

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Additional Geology Flashcards

Cards in this set:

Term
CONTINENTAL CRUST
Makes up how many percent of the earth?
?~? km thick?
What is its composition?
 Definition
30% of earth at 2.7g/cm3
35-70km thick
Composition averages Intermediate to felsic.
Term
OCEAN CRUST
Makes up how much percent of the earth?
?~? km thick?
Compostion?
 Definition
70% of earth at 3.0g/cm3 (oceans)
6-7 km thick
Mafic (basalt)
Term
EVIDENCE FOR PLATE TECHTONICS
Continental drift was suggested by Alfred Wegener in 1915. What did he propose?
 Definition
1) Continents joined in pangaea. (supercontinent)
2) Pangaea broke apart in the Mesozoic, and the continents drifted to present positions.

His Evidence was:
*Jigsaw puzzle fit of continents
*distrubution of fossils (plants & animals)
*how rocks and mountain belts match up across the continents.
Term
SEA FLOOR SPREADING
What is the evidence for sea floor spreading?
 Definition
*Mid ocean ridges/MORs (mountains)
*Abyssal plains- Deep flat areas *Trenches 8-12km deep.
Term
What type of igneous rocks will line up with earths magnetic field?
 Definition
Igneous rocks with Iron and Magnesium.

(magnetometer:studies rocks on the bottom of the ocean/ground)