[meteorite-list] What are those blueberries on Mars?

From: Mark Ferguson <mafer_at_meteoritecentral.com>
Date: Thu Apr 22 10:31:22 2004
Message-ID: <002601c3f282$f83b1e00$aa3d5fcf_at_laptop>

Hi Bjorn and List

They are interesting. Two things come to mind for spherical rocks. One, you
mentioned wind, and you might know theres an area where the rocks seem to
move and leave these curious "tracks" of they're movement across the ground.
It was finally found that wind moved them as it gusted across the area. So,
with the wind speeds possible on Mars, its very possible to tumble and wind
abrade things very well.
The other I thought of requires a body of water. In this also, a change
needed to occur so that oolitic type precipitation could form ( oolites are
small round carbonate balls formed as material precipitates out of solution
and layers form increasing the size).
It is interesting and will be fun to learn what the rover says about them.
Mark

----- Original Message -----
From: "Bjørn Sørheim" <bsoerhei_at_online.no>
To: <meteorite-list_at_meteoritecentral.com>
Sent: Friday, February 13, 2004 11:09 AM
Subject: [meteorite-list] What are those blueberries on Mars?


> Hello List,
> I guess you all have seen those pictures coming from Mars at the
> the Meridiani Planum/Opportunity site.
>
> Embedded in, and eroding out of the bedrock in the sidewall of the
> 20 m crater where Opportunity is located, are those <5mm perfect
> spherical stones.
> They have a different colour than the finely layered matrix they sits in.
> The geologist Steven Squyers said that there were 3 theories about them
> among the scientists at JPL - the 3rd one, by now almost discarded:
>
> 1) They are concretions in the layered deposits, that formed slowly
> after the deposists had been made, probably by water circulating through
> them and slowly crystalizing.
> 2) They are balls made from molten material flung up in the atmosphere
> either by volcanic eruptions or large crater forming impacts.
> 3) They are volcanic 'lapilli' formed as growing spherical balls from
> ash coming out of an erupting volcano. Since these small balls (blueish)
> as photographed by Opportunity, has a different color than the deposits
> they are located in, this seems less likely.
>
> So what are your theories, any thoughts?
> Another theory: Could they be rock fragments rounded by the movements by
> the wind in fine deposits through millions of years at the surface?
>
> Link to picture:
> http://photojournal.jpl.nasa.gov/jpeg/PIA05235.jpg
> http://photojournal.jpl.nasa.gov/targetFamily/Mars (More pictures)
>
> Regards,
> Bjørn Sørheim
>
>
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Received on Fri 13 Feb 2004 05:44:38 PM PST