GEL 130QR Chapter Notes - Chapter 12: Mid-Ocean Ridge, Oceanic Crust, Igneous Rock
Document Summary
Ch 12 - global tectonics: plates and plumes. Continental drift hypothesis - proposed by alfred wegener; introduced the idea of the supercontinent pangea which according to the theory later broke apart; lacked reasonable explanation for why continents moved; preceded plate tectonics. Plate tectonics theory - plates made of the lithosphere, which carry continents as well as oceanic crust, drift on top of the malleable asthenosphere. Surface deformation - interacting rigid plates deform only at their edges without any deformation in the interior, while weak plates deform throughout and semi- rigid deform an intermediate amount. Earthquake data is analysed to measure plate deformation, and therefore rigidness. 80+% of lithosphere deformation occurs at narrow plate boundaries, which means that plates are basically rigid with some semi rigid behavior. Volcano location - volcanos at or near plate boundaries suggest a link between plate motion and location where magma forms.
