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Re: Double impact at K-T boundary ?



I found the PDF site for the paper on Meteor Crater's ejecta blanket.  It 
appears to be a 1994 pub.:

http://www.lpi.usra.edu/meetings/lpsc1994/pdf/1230.pdf

Here's some more refs. on the ejecta blanket (which, by the way, is mostly 
buried under 50K years of eolian and other seds):

Grant, J. A., and P. H. Schultz, The erosional state and style of Meteor 
Crater, Arizona (abstract), Lunar Planet. Sci., XX, 355–356, 1989.

Grant, J. A., and P. H. Schultz, Characteristics of ejecta and alluvial 
deposits at Meteor Crater, Arizona and Odessa Craters, Texas: Results from 
ground penetrating radar (abstract), Lunar Planet. Sci., XXII, 481– 482, 1991.


Grant, J. A., and P. H. Schultz, Erosion of ejecta at Meteor Crater, Arizona, 
J. Geophys. Res., 98, 15,033– 15,047, 1993.

<pb>


---------- Original Message ----------
From: "Phillip Bigelow" <bigelowp@juno.com>
To: dinosaur@usc.edu
Subject: Re: Double impact at K-T boundary ?
Date: Wed, 1 Sep 2010 21:17:49 GMT

There is an interesting paper on mapping the ejecta blanket of Meteor Crater in 
Arizona.

John A. Grant and Peter H. Schultz. Erosion of Ejecta at Meteor Crater, 
Arizona: Further Constraints from
Ground Penetrating Radar. LPSC XXV: 459-460.

Sorry, I don't have the pub. date.  It's a Lunar and Planetary Institute 
Conference pub XXV.  I do have the PDF, though.

Whatever material directly overlies Meteor Crater's ejecta blanket would be of 
use in this discussion.  Some university should fund a graduate student and a 
drill corer and see if charcoal, fern spores, burnt (fired) clay, or any other 
indicators of wildfire or flash-heating can be seen near the crater (say, 1-5 
km from the impact).  It would provide valuable clues to how such thermal 
events would be fossilized, and that data could then be used to extrapolate to 
larger impact events.

Meteor Crater is an excellent subject for such a study because it is a 
terrestrial structure, and it should preserve a lot of proximal-impact site 
effects.

There remain lots of studies yet to be conducted on fossil impact sites.

<pb>

---------- Original Message ----------
From: Lee Hall <paleeoguy@gmail.com>
To: DML <dinosaur@usc.edu>
Subject: Re: Double impact at K-T boundary ?
Date: Wed, 1 Sep 2010 12:53:39 -0500

Is anyone aware of other impacts that have been identified by fern
spikes?  Couldn't fires or volcanic fallout cause something similar?


Lee Hall
Paleontology Undergraduate
Museum of the Rockies
Montana State University
Bozeman, MT
lhall@montana.edu
http://sites.google.com/site/leehallpaleo/Home



On Tue, Aug 31, 2010 at 9:40 AM, Thomas R. Holtz, Jr. <tholtz@umd.edu> wrote:
>
> > From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu]
> > On Behalf Of John Hunt
> >
> > Typical DML reaction!  Loads of discussion on whether Ukraine
> > should or should not be preceded by "the".
>
> True enough.
>
> > Absolutely no discussion, apart from the usual "is Shiva
> > really an impact?",
>
> Let's put this even more specifically: until actual geophysicists and
> structural geologists find evidence this is a crater, the default is that
> there is no there there.
>
> > on whether this satisfies Gerta Keller's
> > double impact theory.
>
> A more interesting question.
>
> Thomas R. Holtz, Jr.
> Email: tholtz@umd.edu   Phone: 301-405-4084
> Office: Centreville 1216
> Senior Lecturer, Vertebrate Paleontology
> Dept. of Geology, University of Maryland
> http://www.geol.umd.edu/~tholtz/
> Fax: 301-314-9661
>
> Faculty Director, Science & Global Change Program, College Park Scholars
> http://www.geol.umd.edu/sgc
> Fax: 301-314-9843
>
> Mailing Address:        Thomas R. Holtz, Jr.
>                        Department of Geology
>                        Building 237, Room 1117
>                        University of Maryland
>                        College Park, MD 20742 USA
>

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