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Evidence for Impact Generated Mass Extinctions
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The Cratering Record
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The Moon
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Impact Craters on the Earth From Grieve 1993
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Barringer “Meteor” Crater, Arizona
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Impact History of the Earth and Moon Sleep et al., Nature 342 139 (1989)
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Impact Event at the 65 myr old Cretaceous/Tertiary Boundary
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Some Consequences of the KT Impact Severe ground shaking, Tsunami Injection of dust into stratosphere, global darkness global fires Atmospheric injection of CO 2 from carbonate target, global warming
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65 myr old Cretaceous-Tertiary Boundary
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Iceland
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Some Consequences of Volcanism Release of toxic pollutants, sulfur, CO 2, fluorine, chlorine Environmental degradation of ecosystems and habitats (e.g. acid rain, ocean anoxia) Atmospheric injection of volcanic CO 2 from eruptions, global warming
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Shocked Quartz, Microspherules, Tektites
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Soot from the 65 myr old K/T Boundary Clay Stevns Klint, Denmark
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Buckminsterfullerene
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Kroto et al., Nature 318, p. 162 (1985)
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Kratschmer et al., Nature 347, p. 354 (1990) Fullerene ‘Bucky’ Generator
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Extraction Protocol for Fullerene Carbon
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Noble Gas Incorporation in Graphitic Smokes E. K. Olsen, T. D. Swindle, J. A. Nuth, F. Ferguson, LPSC XXXI, 2000
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Sublimation of Fullerenes Toluene extracted fullerene from Swindle residue. Fullerene can also be sublimed directly from the soot
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‘Window Mechanism’ for the encapsulation of atoms inside the fullerene cage. A. B. (A) C 60 or buckminsterfullerene. (B) C 60 with an atom inside. (C) C 60 with an atom inside and with a bond broken (open window). (D) Same molecule as (C) but with the atom moving out through the window. C. D.
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Don Davis Fullerenes at the 65 myr old KT Boundary
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Soot from the 65 myr old K/T Boundary Clay Heymann et al., Science 256, 545 (1994)
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The Origin if Fullerenes at the KT Boundary Possible scenarios for fullerenes in the KT impact deposits are: (1) the fullerenes were formed on impact (2) the fullerenes were already present and survived the impact or (3) Fullerenes in the KT sediments were formed as a result of global wildfires triggered by the impact event (Heymann et al., Science 1994)
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KT Fullerene Results Fullerenes isolated from several KTB sites worldwide contained trapped helium that was similar to some meteorites and interplanetary dust particles
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The Great Dying
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Fullerene Results from the PTB The helium concentrations for both the Meishan, China and Sasayama, Japan PTB sediments are similar to the “planetary” component in meteorites (~1.4 x 10 -4 ) Measured 3 He/ 36 Ar also resembles the “planetary” ratio (as opposed to a solar gas reservoir) The 40 Ar/ 36 Ar ratios are a mixture of air and “planetary” (75% to 25%) with an atmospheric 38 Ar/ 36 Ar ratio, also consistent with a carbonaceous chondrite (e.g. Murchison)
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Noble Gas Results for PTB
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Impact Tracers Carbon Isotopes Carbon ‘Soot’ Iridium Chixculub Crater Shattercones Fullerenes Microspherules Shocked Quartz
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The Permian-Triassic Boundary in Antarctica Coal Sac Bluff, Queen Alexandra Range
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Fullerenes w/trapped Noble Gases at Graphite Peak, Antarctica
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Impact Site for the PTB?
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