GEO 1111 Lecture Notes - Lecture 2: Partial Melting, Subduction, Barcode

• School: University of Ottawa
• Department: Geology
• Course: GEO 1111
• Professor: Donald Cummings

Document Summary

Negative feedback dampens initial signal, positive amplifies it. Colours (grey, red- great oxidation event, (with white-snowball earth, globl ice age) green colonization of plants) The dense, primarily solid part of the earth, consisting of rocks and overlying sediment. 50 years ago, it was realized that earth was not static. Rocks of continental crust are different than rocks of the ocean floor. Ocean floor: rich in mg and iron, not a lot of silica (mafic) Continental crust: rich in feldspars and quartz (, rich in silica felsic) Mountain belts: many occyr in continental margins, some margins are devoice of margins. Why? (found by hess, using erosion rates of modern ocean) Narrow strips of feflsic rock that crossed oceans, allowing animals to migrate before again, sinking. (madagascar animals found in madagascar) Did so by having continental crust plowing through oceanic crust. Lehmann: the core is liquid (cid:1005)96(cid:1004)"s (cid:374)ew data e(cid:373)erges: Sonar: sound navigation and ranging (from ww2) depth from time.