Evidence for Impact Generated Mass Extinctions

1. Evidence for Impact Generated Mass Extinctions

3. The Cratering Record

4. The Moon

5. Impact Craters on the Earth From Grieve 1993

6. Barringer “Meteor” Crater, Arizona

7. Impact History of the Earth and Moon Sleep et al., Nature 342 139 (1989)

9. Impact Event at the 65 myr old Cretaceous/Tertiary Boundary

12. Some Consequences of the KT Impact • Severe ground shaking, Tsunami • Injection of dust into stratosphere, global darkness global fires • Atmospheric injection of CO2 from carbonate target, global warming

13. 65 myr old Cretaceous-Tertiary Boundary

15. Iceland

17. Some Consequences of Volcanism • Release of toxic pollutants, sulfur, CO2, fluorine, chlorine • Environmental degradation of ecosystems and habitats (e.g. acid rain, ocean anoxia) • Atmospheric injection of volcanic CO2 from eruptions, global warming

18. Shocked Quartz, Microspherules, Tektites

19. Soot from the 65 myr old K/T Boundary Clay Stevns Klint, Denmark

24. Buckminsterfullerene

25. Kroto et al., Nature 318, p. 162 (1985)

26. Fullerene ‘Bucky’ Generator Kratschmer et al., Nature 347, p. 354 (1990)

27. Extraction Protocol for Fullerene Carbon

28. Noble Gas Incorporation in Graphitic Smokes E. K. Olsen, T. D. Swindle, J. A. Nuth, F. Ferguson, LPSC XXXI, 2000

29. Sublimation of Fullerenes Toluene extracted fullerene from Swindle residue. Fullerene can also be sublimed directly from the soot

30. ‘Window Mechanism’ for the encapsulation of atoms inside the fullerene cage. A. B. (A) C60 or buckminsterfullerene. (B) C60 with an atom inside. D. C. (C) C60 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.

33. Fullerenes at the 65 myr old KT Boundary Don Davis

34. Soot from the 65 myr old K/T Boundary Clay Heymann et al., Science 256, 545 (1994)

35. 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)

36. KT Fullerene Results Fullerenes isolated from several KTB sites worldwide contained trapped helium that was similar to some meteorites and interplanetary dust particles

37. The Great Dying

38. 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 3He/36Ar also resembles the “planetary” ratio (as opposed to a solar gas reservoir) The 40Ar/36Ar ratios are a mixture of air and “planetary” (75% to 25%) with an atmospheric 38Ar/36Ar ratio, also consistent with a carbonaceous chondrite (e.g. Murchison)

39. Noble Gas Results for PTB

40. Impact Tracers Carbon Isotopes Microspherules Carbon ‘Soot’ Iridium Fullerenes Shattercones Shocked Quartz Chixculub Crater

41. The Permian-Triassic Boundary in Antarctica Coal Sac Bluff, Queen Alexandra Range

42. Fullerenes w/trapped Noble Gases at Graphite Peak, Antarctica

43. Impact Site for the PTB?