Alfred Wegener -1912 large “supercontinent” (Pangea) existed and then split into pieces fossil & glacial deposit evidence Wegener not able to provide MECHANISM for his theory Major mechanism later found in the OCEANS Harry Hess - 1960s new ocean basins form from volcanism ocean floor forms IN BETWEEN pieces that have split SEAFLOOR SPREADING | Today’s Tunes Fathoms Below / Under the Sea From soundtrack of Disney’s The Little Mermaid Continental shelf Submarine canyons (cut into the c. slope) Abyssal plain Continental rise Continental slope Seafloor Features: Continental Margins Abyssal plain Seamounts Abyssal Hills (linear hills) Seafloor spreading center (., East Pacific RISE or Mid-Atlantic RIDGE) Deep Ocean Seafloor Features: Deep Ocean Plate Tectonic Boundaries Ridges or Rises Trenches Transform Faults, Fracture Zones The Shifting Crust Continental Drift Alfred Wegener -1912 large “supercontinent” (Pangea) existed and then split into pieces fossil & glacial deposit evidence Wegener not able to provide MECHANISM for his theory Major mechanism later found in the OCEANS Seafloor Spreading & Plate Tectonics Harry Hess - 1960s new ocean basins form from volcanism ocean floor forms IN BETWEEN pieces that have split SEAFLOOR SPREADING Seafloor Spreading & Plate Tectonics Theoretical breakthrough PLATE TECTONICS surface of earth composed of “plates” (LITHOSPHERE) that move on a “conveyor belt” (ASTHENOSPHERE) Evidence for Continental Drift Fit of the continents Correlation of mountain belts Diversity of species correlation of dinosaur species (Pangea) isolation of mammal species (after breakup) Glaciers Important Quote “Relationships known since early in the century yet the validity of continental drift was not generally recognized until the late 1960’s” It took ocean floor data to solidify ideas and convince scientific community! The oceans rule! One Mechanism seafloor-spreading lithosphere asthenosphere Another Mechanism subduction world’s most explosive volcanos are formed over subduction zones Oregon’s Cascades Mtns. over Cascadia Subduction Zone Juan de Fuca plate under N. American plate “Munch and Crunch” “MUNCH” - subduction of oceanic plate under continent or ocean oceanic crust is thin and dense dives “CRUNCH” - collision of continental plates India into Tibet and China continental crust is . | Today’s Tunes Fathoms Below / Under the Sea From soundtrack of Disney’s The Little Mermaid Continental shelf Submarine canyons (cut into the c. slope) Abyssal plain Continental rise Continental slope Seafloor Features: Continental Margins Abyssal plain Seamounts Abyssal Hills (linear hills) Seafloor spreading center (., East Pacific RISE or Mid-Atlantic RIDGE) Deep Ocean Seafloor Features: Deep Ocean Plate Tectonic Boundaries Ridges or Rises Trenches Transform Faults, Fracture Zones The Shifting Crust Continental Drift Alfred Wegener -1912 large “supercontinent” (Pangea) existed and then split into pieces fossil & glacial deposit evidence Wegener not able to provide MECHANISM for his theory Major mechanism later found in the OCEANS Seafloor Spreading & Plate Tectonics Harry Hess - 1960s new ocean basins form from volcanism ocean floor forms IN BETWEEN pieces that have split SEAFLOOR SPREADING Seafloor Spreading & Plate Tectonics Theoretical breakthrough PLATE TECTONICS surface .
