BIOL 2153 Chapter : Genetics Chapter 1 Notes
Document Summary
Mountain building: orogenesis- all processes producing a mountain belt, compressional mountains- most major mountain belts, evidence for crustal shortening and thickening, wrinkles in the crust produced upon cooling, plate tectonics! Convergent boundaries: study old and new (active) structures. Major mountain bets: shields- large, flat exposures of old igneous and metamorphic rocks. Convergence and subduction plates: major features: volcanic arc, partial melting in mantle wedge above sub ducting slab(why?, water gets dragged down with subduction hydrating the rock decreasing the melting point, about 25-30c per km deep. Island arc when on an ocean slab, volcanic are when beneath a continent: deep-ocean trench, where ocean lithosphere bends descending into the mantle. Depth (angle) function of age/temperature of slab and amount of sediment around: fore arc region, between trench and volcanic arc. Accumulation of pyroclastics and sediments: back arc region, other side of volcanic arc (away from trench).
