GEOL 1 Lecture Notes - Lecture 14: Oceanic Basin, Meteorology, Subduction
Document Summary
Plates pull away from each other (rifting) Rising hot asthenosphere partially melts at shallow depths. Solidifies to form new oceanic crust at boundary. Cooling lithosphere sinks, one plate subducts under another. Crust and sediments in sinking plate release water. Asthenosphere in overlying plate in fluxed and melts. Transform motion towards or away from boundaries into motion along the boundary. Passive continental margin - edge of a continent not associated with a plate boundary. Areas of extra heat and uplift from mantle. Appear to be fixed relative to plates. Could be caused by rising plumes of hot mantle. Plate moves over hotspot, creates a chain of volcanoes. Since the earliest maps depict the americas (1500s), some noted that. South america and africa seemed to fit together . Movement of continents first proposed in 1596. Noted fit of south america and africa. Similar fossils of land animals that could not cross oceans on both continents. As lava cools, crystals of magnetite form.
