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Unformatted text preview: localize due to chemical zonation (overhead). As the earth cooled outgassing of the mantle released compounds (water vapor, carbon dioxide, hydrogen, nitrogen) into a primitive atmosphere. Early geologists tried to determine how old the earth was from observations about the features of the earth. Age = Thickness of sedimentary rock/rate of sedimentation. Old (<1.5 billion years) but not old enough. Age = salinity of sea/rate of salt deposition in seas. Again old, but not old enough. Lord Kelvin (of absolute zero fame) calculated the age of earth from its temperature, assuming it was molten at its formation. Gave 100 million years (and gave Darwin a bit of a problem: was this enough time?? Radioisotopes cleared things up (see below)...
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This note was uploaded on 11/06/2011 for the course BIO BSC1010 taught by Professor Gwenhauner during the Fall '10 term at Broward College.
- Fall '10