GEOL 1020 Lecture Notes - Lecture 10: Pleistocene, Till, Sea Surface Temperature
7 Sep 2016
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Southern supercontinent gondwana begins to break apart, leading to the formation of shallow seas. Out of the big 15 (largest animals on earth), 9 were alive during the. Cretaceous: after the cretaceous, land animals begin to shrink, but, marine animals continue to grow (such as large amminoids) Warmer air temperature more h2o per atm warm/wet climate. Greater proportion of 16o in samples more negative 18o:16o ratios. Few to no glacial deposits (such as tills/dropstones) Sedimentary rocks: that are sensitive to climate states/ocean circulation. Stable isotopes: as climate proxies (ex: 18o and carbon) Oxygen isotope proxy = much more negative than pleistocene glaciation, meaning no ice. Proxies of sea surface temperature = warmer equatorial ocean and lower temperature differences between the poles and equator. Coals formed at high latitudes (coal = warm/moist climate. Cretaceous albedo = lower than modern albedo. Modern circumpolar circulation: inefficient redistribution of heat cold ocean and dry earth, active deep water circulation.
