[meteorite-list] Sutter's Mill BSE - two more

From: aerubin at ucla.edu <aerubin_at_meteoritecentral.com>
Date: Fri, 25 May 2012 21:50:44 -0700
Message-ID: <20120525215044.135338ecq1o5dbms_at_mail.ucla.edu>

I just received two small chips this afternoon but haven't had a
chance to look at them yet. But I have seen the images that Sasha
Krot, Mike Zolensky and Carl Agee made. The rock is clearly a
breccia. Sasha's chip has a CM2.0 clast surrounded by slightly less
altered material, probably CM2.2. This is consistent with the
presence of PCP which I believe I saw in some of Carl's images. The
presence of CaS (oldhamite) and reduced phosphides reported by Mike
Zolensky suggests that a projectile of an enstatite chondrite or
aubrite impacted the host and then disrupted. There may have been
subsequent mild metamorphism but little or no aqueous alteration of
the host (or at least Mike Zolensky's piece) at that point; otherwise
the oldhamite would have been destroyed. The rock has unique
features, but other meteorite breccias contain clasts of diverse
groups. Such rocks include Kaidun, Galim, Bencubbin, Almahata Sitta,
even Murchison.
Alan





Quoting Carl Agee <agee at unm.edu>:

> Hi Richard,
>
> I haven't seen a thin section of Sutter's Mill yet, but my guess is
> that it will be very dark, just like the meteorite, so maybe not that
> illuminating. I prefer backscatter electron images because they not
> only show texture, but also image chemical compositional variations.
> Like the dark olivines in my images?- they are Mg2SiO4-rich, the
> light shaded olivines are Fe2SiO4-rich. Bright patches indicate high
> iron or Ti or Cr, and so on.
>
> As to the CaO, the electron microprobe does not do carbon very well so
> it usually comes up with low totals on carbonates. I looked at the
> data today and we found 4 separate crystals with this composition in
> one of the small SM sections -- after perusing the CM literature
> today, I am pretty sure this is calcite or aragonite -- thought by
> some to form during aqueous alteration and commonly found in CMs.
>
> With respect to the classification and type, I will leave that to the
> unequilibrated chondrite experts like Jeff Grossman and Alan Rubin.
>
> MetSoc will be very interesting this year: Tissint, Sutter's Mill, and
> NWA 7034. You haven't heard about NWA 7034? Oh you will...
>
> Carl Agee
>
>
> On Fri, May 25, 2012 at 7:04 PM, Richard Montgomery
> <rickmont at earthlink.net> wrote:
>> Carl and List,
>>
>> I'm struck by the chondrule variation...can't wait to see a TS (hi
>> Anne!)....so it's time to ask about the rabbit hole:
>>
>> As I mentioned I'm just guessing here....not a CM2, due to chondrules
>> actually so present, right? Not a CM3 either (if there ever is such a thing)
>> due to the rim alterations and aqueous stuff; dark matrix like a CM, yet
>> more crowded chondrules; complete CaO crystals; lacking so far of seeing any
>> CAIs....what's your guess at this point??
>>
>> Next Halloween I can dress up as a petrologist scientist....but won't fool
>> anyone. ?Fun to speculate, though.
>>
>> Richard M
>>
>>
>> ----- Original Message ----- From: "Carl Agee" <agee at unm.edu>
>> To: "meteoritelist meteoritelist" <meteorite-list at meteoritecentral.com>;
>> "Jeff Grossman" <jngrossman at gmail.com>
>> Sent: Friday, May 25, 2012 2:03 PM
>> Subject: Re: [meteorite-list] Sutter's Mill BSE - two more
>>
>>
>>> Jeff,
>>>
>>> You mean the area in the SW quadrant? It's permeated with the bright
>>> material? It could be sulfide, but I didn't get a chance to EDS or
>>> probe it yesterday. It's all somewhat bewildering, there is so much
>>> look at, so I am starting with the simple stuff that give good
>>> microprobe totals -- haha!. Beware of this meteorite! Like going down
>>> the rabbit hole....
>>>
>>> Carl
>>>
>>>
>>> -----------------------------------------
>>> Carl,
>>>
>>> What's the difference between the two lithologies visible in the first
>>> of these two photos?
>>>
>>> Jeff
>>>
>>> On 5/25/2012 2:19 PM, Carl Agee wrote:
>>>
>>>>
>>>> http://www.facebook.com/photo.php?fbid=4042491099560&set=a.1076549432872.2012978.1200325441&type=1&ref=nf
>>>
>>>
>>>>
>>>> http://www.facebook.com/photo.php?fbid=4042494859654&set=a.1076549432872.2012978.1200325441&type=1&ref=nf
>>>
>>>
>>>>
>>>
>>>
>>> --
>>> Carl B. Agee
>>> Director and Curator, Institute of Meteoritics
>>> Professor, Earth and Planetary Sciences
>>> MSC03 2050
>>> University of New Mexico
>>> Albuquerque NM 87131-1126
>>>
>>> Tel: (505) 750-7172
>>> Fax: (505) 277-3577
>>> Email: agee at unm.edu
>>> http://meteorite.unm.edu/people/carl_agee/
>>> ______________________________________________
>>>
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>>
>
>
>
> --
> Carl B. Agee
> Director and Curator, Institute of Meteoritics
> Professor, Earth and Planetary Sciences
> MSC03 2050
> University of New Mexico
> Albuquerque NM 87131-1126
>
> Tel: (505) 750-7172
> Fax: (505) 277-3577
> Email: agee at unm.edu
> http://meteorite.unm.edu/people/carl_agee/
> ______________________________________________
>
> Visit the Archives at
> http://www.meteoritecentral.com/mailing-list-archives.html
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>
Received on Sat 26 May 2012 12:50:44 AM PDT