Earth Sciences 1083F/G Lecture : Lecture 26 - Cretaceous-Tertiary Mass Extinction
25 Jan 2012
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Document Summary
due to melting of rock be energy of bolide impact. found in the boundary sediments of the gulf of mexico: soot particles in boundary clay. suggest global wildfires associated with ignition of large amounts of dead plant matter: fern spike/pollen trough. pollen/spore ratio decreases at same level as the iridium spike. no sunlight = no photosynthesis = death through food chains. earth in darkness for at least 6 months after asteroid hit the: k-t impact winter. believed to have been deposited by tsunami generated by the impact: ejecta blanket, belize. poorly sorted debris believed to be ejecta deposited close to the crater: fullerines (molecular cage of carbon atoms) contain helium 3 instead of more common helium 4. elevated to helium 3 at the k-t boundary y does survival of the fittest work during mass extinction: in mass extinctions, the specialists lose, early mammals survived because of their generalized life habits.
