PHYS 037 Lecture Notes - Lecture 13: Mantle Convection, Supercontinent, Cambrian Explosion
6 Dec 2016
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Document Summary
Brief history of the earth: earth is 4. 56 billion years old. Largest division of geologic time, includes multiple eras. One subdivision of an eon and includes multiple periods. A geologic time representing one subdivision of an era. One subdivision of a period: earth was very hot at its origin, violent impacts from planetesimals and other bodies were common, elements within earth differentiated to form layered internal structure. Heavier elements sank to the core of the earth. Lighter elements moved towards the surface: eon, era, period, epoch. Cambrian explosion: all major groups of animals alive today originated during this radiation. In the cambrian period, a major radiation of life occurred: alfred wegener (1915) proposed that all of the continents were once part of a large, based on. Distinctive fossil groups found in africa and south america. Wegener proposed a mechanism for drift: problems, continents plowed through solid ocean oor, tidal forces drove the motion.
