GL101 Chapter Notes - Chapter 12: Convergent Boundary, Mantle Convection, Oceanic Trench
Document Summary
Plate tectonics: continental drift: alfred wegener proposed continents moved about the surface of the planet however his theory was not widely accepted, plate tectonics: currently understanding of how continents move. Continental drift: evidence across the atlantic ocean: Fit of continents: fit together like a jigsaw puzzle. Fossil evidence: same fossils found on separated continents. Rock type and structural similarities: rocks on one continent match those on another continent. Paleo-climatic evidence: evidence for ancient glacial ice explained by a super- continent: wagner proposed pangaea: single super continent that broken up approximately 200 million years ago to form the continents we know today. Problem: lacked a convincing mechanism to allow continents to plow through the oceanic crust. Evidence that lead to the theory of plate tectonics: apparent polar wandering, mapping of the sea floor, magnetic pole, radiometric dating of the sea floor, mapping of earthquake activity. The seafloor spreading hypothesis: hess proposed that:
