EARTHSS 1 Lecture Notes - Lecture 5: Continental Drift, Plate Tectonics, Outer Core

• School: UC-Irvine
• Department: Earth System Science
• Course: EARTHSS 1
• Professor: Julie Ferguson

Document Summary

Terrestrial planets (earth) undergo differentiation (melting and separation into layers) Energy from collisions and radioactive decay results in melting. Layers of different composition: core (iron, mantle (solid, crust. Layers of different strength: mesosphere (mantle): hot but strong due to high pressure, asthenosphere (liquid outer core): hot, weak, plastic, lithosphere (crust): cool, rigid, brittle. Matching fossils on land masses far apart. Matching rocks and structures on the edges of continents. Evidence from fossils and rocks showing climate zones did not match current continent positions. Mai(cid:374) (cid:396)easo(cid:374) wege(cid:374)e(cid:396)"s (cid:272)o(cid:374)ti(cid:374)e(cid:374)tal d(cid:396)ift (cid:449)as (cid:374)ot a(cid:272)(cid:272)epted: Because we had not yet discovered the mid-ocean ridges or subduction zones at the bottom of our oceans and so had no mechanism to explain how continents moved around. Paleomagnetism (magnetic field of the past): provides protection from solar winds and cosmic rays: ea(cid:396)th"s (cid:373)ag(cid:374)eti(cid:272) field is (cid:272)aused (cid:271)y (cid:272)o(cid:374)(cid:448)e(cid:272)tio(cid:374) i(cid:374) the li(cid:395)uid oute(cid:396) (cid:272)o(cid:396)e.