Re: Bolide sites?

["Thomas R. Holtz, Jr." <th81@umail.umd.edu>]

At 10:15 AM 7/1/99 -0700, Bill Adlam wrote:
>Tom wrote (in reply to Dan Tapster):

>> Meteor Crater near Winslow, Arizona is about 1.2 km across...
>> Wolf Creek crater in Western Australia is about 0.9 km across...
>
>So they are much smaller than the probable K/T crater.

Oh my yes!

>> The trace of Manicouagan crater (a Late Triassic impact 70 km across)
>> is
>> visible due to erosion by glaciers, but a) it is not obviously a
>> crater to a
>> ground based observer and camera and b) I don't think the BBC will
>> budget
>> for sending a camera crew up in a Space Shuttle or other launch
>> vehicle in
>> order to film it from space...
>
>Still pictures could be generated by Landsat, SPOT or some other remote
>sensing service.  And the area may well have been photographed from
>space at some point.

It has: almost every modern historical geology book and a few dinosaur books
have the Landsat shot of Manicouagan.

However, I think the discussion has moved a bit far afield from the original
point (as I percieved it):

Dan Tapster of working on a documentary for the BBC (on mammal evolution).
He is looking for an easy-to-reach, visible crater.  That sounds to me like
they want to get a film crew there, and maybe even a documentary presenter
for on camera narration.  That would be EXCEEDINGLY difficult to do from
orbit (and VERY expensive).  Also, from the ground Manicoagan wouldn't look
very crater-like: its scale is just too big. The crater nature of the region
is only visibly apparent from high above.

(Of course, voice-over narration while showing camera shots of Manicoagan
might work as well). 

>
>Some large bolide craters are easily seen and have not been
>substantially eroded.  They can't be considered 'convenient to reach',
>though, as they're on the moon.

That discussion went on on the Vert Paleo list (good point, though).

                        Thomas R. Holtz, Jr.
                        Vertebrate Paleontologist
Deptartment of Geology                  Director, Earth, Life & Time Program
University of Maryland                  College Park Scholars
College Park, MD  20742       
Webpage: http://www.geol.umd.edu        Phone:301-405-4084
Email:tholtz@geol.umd.edu               Fax:  301-314-9661