GEOG 101 Lecture Notes - Lecture 11: Abraham Ortelius, Continental Drift, Thermal Expansion
28 Sep 2018
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Idea that continents and other landmasses have shifted: used to be together, but drifted apart. Abraham ortelius in 1596: the hypothesis that co(cid:374)ti(cid:374)e(cid:374)ts (cid:858)drift(cid:859) (cid:449)as first put for(cid:449)ard. Alfred wegener: german climatologist, continents moved (concept, wrote a book about this, pangaea, gondwana, laurasia, found that continents actually stay together. Similar geology: type, age, structure of mountain ranges. Increase lunar gravitation: geophysical force caused by earth rotation (now known too small) Radioactive dating: the absolute age of rocks, look at layer sediments to help. Paleomagnetism: reconstructed locations of continents, 200 ma continents joined together, more importantly, lead to sea floor spreading theory. Formally proposed by american geologist harry h hess. Explaining the opening of atlantic ocean and east africa rift. 2 tectonic plates are spreading apart along the mid-atlantic ridge. Arthur holmes: early supporter of weg(cid:374)er(cid:859)s continental drift theory, earth(cid:859)s (cid:373)a(cid:374)tle co(cid:374)tai(cid:374)s co(cid:374)(cid:448)ectio(cid:374) cells due to radioacti(cid:448)e heat, plates driven by convection currents. Thermal convection: diffuse upwelling, slab suction, slab pull.
