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
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