Carl et al.

Regarding the Block Island meteorite on Mars...

I asked "Why does it have regmaglypts?" of our local Mars expert, Ray Arvidson, who is Deputy Principal Investigator of the Mars Exploration Rover Mission. He had mentioned the existence of the meteorite to me several weeks ago. He said that the fall happened "4 billion years ago," when Mars had a more substantial atmosphere. This makes sense to me because we've never seen a meteorite this size on the Moon. On the Moon meteoroids impact at several tens of kilometers per second, and vaporize. In order to survive as a whole rock, Block Island must have been decelerated by an atmosphere. (I'm sure that meteoroids hitting Mars are impacting at lower velocities than those hitting Earth-Moon, but I don't know the numbers.)

The area where the meteorite was found is a deflation surface - like Roosevelt Co., NM, and places in Antarctica. It was buried for a long time and then exposed when the dust blew away. They know it's a deflation surface because the surface is "young" - the crater count is very low.

Only after writing the above did I find some 3D glasses and actually looked at the image. Most of the "holes" don't look so much like regmaglypts to me. Maybe some are chemical weathering features. There will probably be some more info about this meteorite coming out later. Ray said that there is a great interest on what kind of chemical reactions it's experienced.

Randy Korotev
Washington University




At 11:54 07-08-09 Friday, you wrote:
Pete, List,
Very interesting photo.
I have a question about it's morphology?
Why does it look like that? Why does it have so many holes / dents?
Given the atmosphere on Mars being so thin compared with Earth, I thought Earths Atmosphere is what caused this type of erosion of surface materials? It was my understanding that the material ablated away as it passed through the atmosphere . If that is so then why does it look the same on Mars. Is it possible that maybe it already looked like this before it entered Mars' atmosphere?
Just curious.
--
Carl or Debbie Esparza
IMCA 5829
Meteoritemax


---- Pete Pete <rsvp...@hotmail.com> wrote:
>
>
>
> Hi, all,
>
> An incredible view of a Martian iron in fine detail!
>
> (note the full resolution link)
>
> http://www.nasa.gov/mission_pages/mer/images/mer20090806.html
> http://www.nasa.gov/mission_pages/mer/images/mer20090806.html
>
>
> It suggests red/green, but red/blue works fine.
>
>
> Cheers,
> Pete
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