[meteorite-list] Columbian Impact Structure (??) and Deccan Basalts was “Multiple Impact and 73P
From: Paul <bristolia_at_meteoritecentral.com>
Date: Sun Apr 2 00:14:05 2006 Message-ID: <20060401170542.22996.qmail_at_web36213.mail.mud.yahoo.com> In ?Multiple Impact and 73P(was..More Evidence Chicxulub..)?, MexicoDoug at aol.com wrote >Sterling W. writes: << Keller-Harting get lots of press, but nobody <<is convinced by them but them... >> > >Hola Sterling, > >The idea that multiple impacts ocurred doesn't >seem to far fetched, and we can basically thank >them for introducing it as potentially more viable >and consistent based on top-notch fieldwork, not >just astronomical mullings.? Columbian Impact Structure ?? This discussion reminded me a geologic structure, which was found in seismic surveys made for oil and gas exploration, lying beneath the Columbian continental shelf. It was a huge, possibly larger than Chicxulub, circular stucture, which was a candidate for the K/T impact site, until it was found. Once Chicxulub was found and published, it seems to have been completely forgotten. Does anyone know if anything had ever been published on it? Might this still be an alternate possibility for the K/T killer? The Deccan Flood Basalts, An Additional Complication To further complicate the K/T boundary controversy, there are these findings and interpretations: India?s Smoking Gun: Dino-Killing Eruptions Geological Society of America Press Release, 9 August 2005 http://www.geosociety.org/news/pr/05-27.htm The abstract stated: ?In fact, most mass extinctions over the past 300 million years have coincided with large volcanic events, said Chenet. The general rule is that massive volcanism like the Deccan Traps correlates with all major mass extinctions in Earth's history, she said.? Another article is ?Volcanic prepping for dinosaur extinction? from the October 2005 Geotimes at: http://www.agiweb.org/geotimes/oct05/NN_volcextinction.html The abstract discussed in the above articles is: Chenet, A.-L. Courtillot, V., Fluteau, F., Besse, J., Subbarao, K. V., Khadri, S., Bajpai, S., and Jay, A., 2005, Magnetostratigraphy of the Upper Formations of the Deccan Traps: an Constraint on the Timing of the Eruptive Sequence. Session no. T9. Large Igneous Provinces: Their Biotic, Climatic, and Oceanic Impact, Earth System Processes 2 Meeting, August 8-11, 2005. Calgary, Alberta. http://gsa.confex.com/gsa/2005ESP/finalprogram/abstract_88502.htm I find it fascinating that there seems to exist a far better correlation between eruption of massive flood basalts and mass extinctions than there is between impact events and mass extinctions. This is discussed in an interesting abstract: Courtillot, V., and Thordarson, T., 2005, Flood basalts appear to be the main cause of biological mass extinctions in the Phanerozoic. Geophysical Research Abstracts, Vol. 7, 11196, 2005 SRef-ID: 1607-7962/gra/EGU05-A-11196 http://meetings.copernicus.org/egu2005/download/EGU05-J-11196-1.pdf The who, what, and when of the K/T extinction event is far from a settled matter. Best Paul __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com Received on Sat 01 Apr 2006 12:05:42 PM PST |
StumbleUpon del.icio.us Yahoo MyWeb |