ERTH 1011 Lecture Notes - Lecture 1: Volcanic Glass, Outer Core, Oceanic Crust
24 Jan 2015
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Document Summary
Geosphere: the dense primarily solid part of the earth that consists of rocks and overlying sediment. Scientists proposed the idea of land bridges- narrow strips of low-density felsic rock that crossed oceans. It had risen and sunken over time allowing animals to pass. Fauna in madagascar (animals) were similar to fauna in india which was taken as evidence that the bridge existed. The continents have drifted across earth over time. They did so by plowing through oceanic crust. Idea proposed by alfred wegener, german meteorologist (1880-1930) Seismic studies were starting to reveal that the earth was layered- liquid outer core and silly putty like mantle- were convecting. (were transferring heat) to the surface of the earth. The heat was generated by decaying radioactive materials within earth. Inge lehmann(1888-1933) believed outer core of earth was liquid. It was rejected in 1960 because it lacked clear evidence and conjured many unanswered questions.
