|
|
 |
|||||||||||||||||
|
|||||||||||||||||
 |
|||||||||||||||||
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
1 Geo Eco Arc Research, 16305 St. Mary's Church Road, Aquasco, Maryland 20608, USA
Most of the 3-mm-thick globally distributed Chicxulub ejecta layer found at the Cretaceous-Tertiary (K-T) boundary was deposited as condensation droplets from the impact vapor plume. A small fraction of this layer (<1%) is clastic debris. Theoretical calculations, coupled with observations of the coarse dust fraction, indicate that very little (<1014 g) was submicrometer-size dust. The global mass and grain-size distribution of the clastic debris indicate that stratospheric winds spread the debris from North America, over the Pacific Ocean, to Europe, and little debris reached high southern latitudes. These findings indicate that the original K-T impact extinction hypothesis—the shutdown of photosynthesis by submicrometer-size dust—is not valid, because it requires more than two orders of magnitude more fine dust than is estimated here. Furthermore, estimates of future impact hazards, which rely upon inaccurate impact-dust loadings, are greatly overstated.
Key Words: Cretaceous-Tertiary boundary • mass extinctions • Chicxulub crater • impact crater • ejecta
This article has been cited by other articles:
|
|
 |
|
  C. M. Belcher, P. Finch, M. E. Collinson, A. C. Scott, and N. V. Grassineau Geochemical evidence for combustion of hydrocarbons during the K-T impact event PNAS, March 17, 2009; 106(11): 4112 - 4117. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. C. Harvey, S. C. Brassell, C. M. Belcher, and A. Montanari Combustion of fossil organic matter at the Cretaceous-Paleogene (K-P) boundary Geology, May 1, 2008; 36(5): 355 - 358. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Kelley The geochronology of large igneous provinces, terrestrial impact craters, and their relationship to mass extinctions on Earth Journal of the Geological Society, September 1, 2007; 164(5): 923 - 936. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Aberhan, S. Weidemeyer, W. Kiessling, R. A. Scasso, and F. A. Medina Faunal evidence for reduced productivity and uncoordinated recovery in Southern Hemisphere Cretaceous-Paleogene boundary sections Geology, March 1, 2007; 35(3): 227 - 230. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C.M. Belcher, M.E. Collinson, and A.C. Scott Constraints on the thermal energy released from the Chicxulub impactor: new evidence from multi-method charcoal analysis Journal of the Geological Society, July 1, 2005; 162(4): 591 - 602. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Land plant extinction at the end of the Cretaceous: a quantitative analysis of the North Dakota megafloral record Paleobiology, September 1, 2004; 30(3): 347 - 368.
|
|
|
|
 |
|
 L. Becker, R. J. Poreda, A. R. Basu, K. O. Pope, T. M. Harrison, C. Nicholson, and R. Iasky Bedout: A Possible End-Permian Impact Crater Offshore of Northwestern Australia Science, June 4, 2004; 304(5676): 1469 - 1476. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Macleod Identifying Phanerozoic extinction controls: statistical considerations and preliminary results Geological Society, London, Special Publications, January 1, 2004; 230(1): 11 - 33. [Abstract] [PDF]
|
|
|
|
|
|
C. M. Belcher, M. E. Collinson, A. R. Sweet, A. R. Hildebrand, and A. C. Scott Fireball passes and nothing burns--The role of thermal radiation in the Cretaceous-Tertiary event: Evidence from the charcoal record of North America Geology, December 1, 2003; 31(12): 1061 - 1064. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. G. MacLeod, P. D. Fullagar, and B. T. Huber 87Sr/86Sr test of the degree of impact-induced slope failure in the Maastrichtian of the western North Atlantic Geology, April 1, 2003; 31(4): 311 - 314. [Abstract] [Full Text] [PDF]
|
|
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
