GEOL 21062 Lecture Notes - Lecture 3: Scandinavia, Radiometric Dating, Mesosaurus
31 Jan 2020
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Document Summary
Alfred wegener published his hypothesis of continental drift. He hypothesized: existence of single super-continent pangaea ( pan - g - uh ) ~ 200 million years ago pangaea broke into smaller pieces, which drifted to their present positions. Mountain belts on one continent match up to the rocks found on another continent. Example: rocks of similar age & structure are found in the: appalachians (eastern u. s. , british isles, scandanavia. Paleoclimate evidence: gondwanaland glacial deposits are today scattered around on different continents , but when pangea is reassembled, these glacial deposits all match up perfectly! Fossil evidence: distributions of many fossil species found on different continents only make sense in light of continental drift, mesosaurus, lystosaurus. Radiometric dating was not developed until the 1950"s. It is in this way that scientists learned about: remnant magnetism: the orientation of the magnetic field of, periodic reversals of the polarity of the field. They loose magnetization when heated above curie point (580oc for iron)
