Geology 101Lab 1Monday, September 1, 2014Continental Drift- “Continental drift” was a precursor to Plate Tectonic Theory- It was proposed by Alfred Wegener in 1915- He noted the jigsaw puzzle fit of the coastlines on opposite sides of the Atlantic- He proposed “Pangea” existed, a super continent- He was criticized for it. His theory was never accepted in his lifetimeSeafloor Spreading- Early 1960s - Harry Hess suggested that new oceanic crust are created in oceanic ridges such as the Mid Atlantic Ridge- As the process goes on the seafloor, the floor is carried apart like a conveyor belt- He also suggested crust descends in the vicinity of deep ocean trenches- Seafloor spreading combined with a greater understanding of remnant magnetism preserved in oceanic rocks developed into the unifying theory called Plate TectonicsEarth’s Layered Structure- Crust, mantle, core, all have a distinct chemical composition- Crusto 5-70 km (top layer)- Mantleo 2900 km- Coreo 3480 km- The lithosphere is the rigid outer shell of eartho 100 km- The temperature-pressure regime in the upper asthenosphere result in a fluid-like behaviorPlate Tectonics- 7 major plates- All their major interactions occur at their boundariesPlate Boundaries - Divergento 2 plates move aparto ex: Mid Atlantic ridge- Convergento Plates moving together o Several types of convergent marginso Can cause volcanic eruptionso Two continents can collide Ex: Himalaya Mountains- Transformo Plates slide horizontally past one
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