CAS ES 351 Lecture Notes - Lecture 18: Seafloor Spreading, Stoma, Continental Margin
23 Mar 2019
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Document Summary
~this temp profile is known as the cretaceuos target signal . Benthic foraminifera tell us about the temperatures of deep water. Shallow waters can vary a lot in isotopes and other factors to determine past conditions. In the cretaceous, the temperatures were warmer, and it was a bit colder at the poles than at the equator, but the difference in pole to equator temp gradient was much smaller than at present (equable climate) We can change co2 levels, cloud cover, sea ice, ratio of water to land, and geography. Cretaceous co2 reconstructions largely based on fossil leaf stomatal density, geochemical models, paleosols. Our climate models are a little unpredictable because we don"t understand the physics of clouds. Faster sea floor spreading might be the reason why the cretaceous had so much co2. ~we get a lot of uncertainty from this.
