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Re: Clarification of impact event at K-T



>> The five craters are: Chicxulub (Yucatan, Mexico), Shiva (offshore
>> western
>> India), Small Point Maine (offshore Maine & Massachusetts),

This has been featured in a few GSA talks, but I don't know if it is
written up. And as far as I recall, there was no secure age data for it.

> Boltysh
>> (Ukraine), and Silverpit (North Sea).
>>
>> All these craters date near 65 Ma
>
> I haven't heard of the Small Point Maine crater and don't remember the age
> of the Boltysh one.

Recent work on melts point towards a K/Pg age for Boltysh. However, at
only 23 km across, it in and of itself wouldn't really be a contributor to
the damage (although it is likely a splinter of the Big Daddy).

> The Shiva "crater" is not a crater, however;
> Chatterjee
> just interpreted a crater into a seafloor map without considering what the
> geological evidence actually says and without explaining why the shape has
> a
> corner -- elliptical would be fine, but it isn't elliptical. Ironically,
> it's way too _big_ for a crater associated with this mass extinction!
>
> Silverpit is real and has the right age, last time I checked at least.
>
>
Actually, Silverpit is Eocene:
http://jgs.lyellcollection.org/cgi/content/abstract/165/4/781

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, Earth, Life & Time Program, College Park Scholars
http://www.geol.umd.edu/~jmerck/eltsite/
Fax: 301-405-0796

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
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