ESS 330 Lecture Notes - Lecture 2: Mid-Ocean Ridge, Plate Tectonics, Oceanic Crust
21 Feb 2017
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Document Summary
Oceanic: 2. 7-3 g/cm3: mantle: 3-6 g/ cm3, core: 9-13 g/cm3. Physical compositions: inner core- solid, highest temp, highest pressure, outer core- liquid, mesosphere- 700-2800km, solid, asthenosphere- 100-700km, plastic, flow, convection, lithosphere- 0-100km, solid, includes crust, lowest temp, lowest pressure. Isostatic rebound- rising of crust formerly weighed down by glacier ice. Symmetric pattern of age distriuting about mid ocean ridge: oldest is only 180 million years old (my) Divergent: plates are moving apart, occur at mid ocean ridges and rift valleys, subsidence- slowly goes down, ocean plate is subsiding because it is cooling, types of spreading centers. Convergent: plates move toward eachother, ocean crust can be destroyed during subduction. Oceanic trench, oceanic arc: deep focus earthquakes, mineral structure is changing, types. Ocean trnches form and continental volcanic arcs. The older the oceanic crust the more dense that it is. Transform: offsets oriented perpendicular to mid-ocean ridge.
