Objectives :
Objectives Describe Wegener’s theory of continental drift and explain why it was not accepted at first Define tectonic plates
Slide 3:
In 1912, Alfred Wegener first proposed that the continents had started off as one huge land mass, that drifted apart.
Evidence for Continental Drift:
Evidence for Continental Drift Wegener found rocks of similar composition and age on Africa and S. America Similar Rock Types
Evidence for Continental Drift:
Same species of land animals found on opposite sides of Atlantic Ocean Evidence for Continental Drift Fossil Evidence
Evidence for Continental Drift:
Coal deposits and fern fossils in Antarctica Glacial deposits in India, S. America, Africa, Australia Evidence for Continental Drift Climate Evidence
Evidence for Continental Drift:
Similar mountain ranges on different continents now separated by water Evidence for Continental Drift Mountain Belts
Earth’s Structure:
Earth’s Structure Composition: described by differences in chemical make up
Slide 9:
Physical properties of the earth’s layers: Lithosphere Asthenosphere Mesosphere Outer core Inner core
Tectonic Plates:
Tectonic Plates Pieces of lithosphere that move around on top of the asthensphere The Earth has 14 major tectonic plates, and 38 minor plates, for 52 plates total