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Unformatted text preview: er direction... Continued volcanism causes CO2 levels to rise Eventually, CO2 levels became very high Earth warmed up--perhaps very rapid up-- Cf. enhanced greenhouse effect Ice melted near equatorial regions Albedo decreased, accelerating the warming , g g Evaporation increased, increasing water vapor in the atmosphere The Freeze-Fry: The Fry, cont. FreezeGreenhouse effect became even stronger, stronger, accelerating the warming CO2 levels now very high Atmosphere is incredibly hot (possibly ~50C = 122F) ~50 122 "Hothouse world" 28 2/19/2008 Snowball Earth: Explaining the geology Carbonates directly over tillites, tillites, Explanation: Snowball conditions rapidly changed to hothouse conditions Return of BIFs, Explanation: Ocean was capped by ice for ~10 million years Photosynthesis effectively shut down & seawater became anoxic 29...
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- Spring '08