GEOL 118 Lecture Notes - Lecture 28: Cenozoic, Weathering, Global Cooling
27 Apr 2016
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Geol 118 - lecture 29 - climate change ii. Effect of greenhouse gases on climate - geologic examples: Geologic examples generally involve several factors, notes emphasize most important controls only. Early earth (4. 6-3 billion years ago; early precambrian) was hothouse climate. Most of current earth"s carbon in limestone. End of mesozoic/beginning of cenozoic (100-50 mya) was hothouse climate, resulted in flooding of much land on continents. Major reason for warm climate is high levels of atmospheric co2 from greater volcanism by rapid sea floor spreading associated with opening of atlantic ocean. Cenozoic cooling (50 +2 mya) - after hothouse climate, earth cooled progressively. Beginning ~45 mya, india began to collide with eurasia. Creation of enormous mountain range exposed enormous amount of silicate and carbonate rock to chemical weathering. Steep slopes erode quickly, exposing new fresh rock.
