[meteorite-list] Official Announcement NWA 6077 is Paired with NWA 5400

[Greg Catterton]

Its great that there is such a nice amount of this material when considering all the pairings... With over 10kg of this material in pairings known so far, I am willing to bet there is likely a good amount more still.
I bet the Brachinties are coming out of the woodwork to be tested.

Greg Catterton
www.wanderingstarmeteorites.com
IMCA member 4682
On Ebay: http://stores.shop.ebay.com/wanderingstarmeteorites
On Facebook: http://www.facebook.com/WanderingStarMeteorites


--- On Tue, 10/5/10, John higgins <geohiggins at yahoo.com> wrote:

> From: John higgins <geohiggins at yahoo.com>
> Subject: [meteorite-list] Official Announcement NWA 6077 is Paired with NWA 5400
> To: meteorite-list at meteoritecentral.com
> Date: Tuesday, October 5, 2010, 9:26 AM
> Official Announcement
>  
> NWA 6077 IS PAIRED WITH NWA 5400
>  
> North West Africa 6077 Description:
> An olivine-rich assemblage with cumulate (or possibly
> metamorphic) texture 
> exhibiting triple junction grain boundaries. Olivine
> (Fa30.2-30.7), 
> orthopyroxene (Fs24.1-24.5Wo2.1-2.0), clinopyroxene
> (Fs9.4-10.0Wo44.0-43.5), 
> altered kamacite, chromite, chlorapatite, Ni-bearing
> troilite and/or pyrrhotite. 
> No plagioclase was found. Analysis conducted at the
> Carnegie Institution of 
> Washington show that the oxygen isotopic composition of
> this specimen plots on 
> the Terrestrial Fractionation Line. In conjunction with the
> mineral compositions 
> and texture, this establishes that NWA 6077 is paired with
> NWA 5400.
>  
> The averages of the two Oxygen Isotope Results are: 
> d17O = 2.780, d18O = 5.358, D17O = -0.019 (all in per mil)
>  
> This brachinite was recovered out of Morocco in 2008 as
> one whole stone and 
> purchased by John Higgins. It was submitted for
> classification to Dr. Tony 
> Irving and was given the provisional classification number
> of NWA 6077. This 
> meteorite has a modest TKW of less than 1000g after the
> type specimen was 
> removed.
>  
> Personal Notes: Although I suspected that the two were
> possibly paired due to 
> similarities in visual observations and classification
> compositions, I felt it 
> was important to wait for secondary Oxygen Isotope results
> to come in which have 
> recently confirmed the results beyond a reasonable doubt.
> There was also another 
> important factor besides Oxygen Isotope testing that had
> to be taken into 
> account. Orthopyroxene which is present in NWA 5400 was
> missed the first time 
> around in NWA 6077 because it looks identical to
> clinopyroxene in back-scattered 
> electron images. However further in-depth
> microprobe studies of the thin section 
> have confirmed the presence of orthopyroxene, and are
> now noted in the updated 
> description. I feel that making a self pairing based upon
> my own 
> visual observations, is not only unethical, inappropriate,
> and akin to pirating, 
> but would only feed the controversies regarding this
> meteorite without the 
> scientific testing data to back up such speculation, such
> action would be 
> premature, immoral and unfair to Greg Hupe and NWA 5400
> after all the time and 
> effort he put into the study of what has become one of the
> most important 
> meteorite finds in history.
>  
> Have a Great Day!
> John Higgins
> IMCA#9822
> 
> 
>       
> ______________________________________________
> Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html
> Meteorite-list mailing list
> Meteorite-list at meteoritecentral.com
> http://six.pairlist.net/mailman/listinfo/meteorite-list
>