[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

New Kitchener meteorite article

Thought some of you may be interested...
THE KITCHENER, ONTARIO METEORITE: FELL 0830 EDT (LOCAL TIME), JULY 12,
1998 

Presented by Rucklidge, John C.. 
Authors:
      Wilson, Graham C., 
      Herd, Richard K., 
      Wacker, John F..

Key words: Chondrite;Kitchener;Ontario;L6 

In Session 70     Planetary Geology (Posters) Tuesday, Tuesday, October
26, 1999 AM in Room: Poster Hall at 08:00 AM for . 

Abstract: The Kitchener meteorite fell on a golf course in the valley of
the Grand River. A brief search and local media exposure failed to
unearth additional samples. The stone was spheroidal, circa 4.5 cm in
diameter, weight 202 g, with a near-complete black fusion crust.
Gamma-ray counting revealed Sc-46, consistent with the date of fall. The
major minerals are olivine, orthopyroxene, feldspar, troilite,
kamacite and taenite. The mode comprises 35 volume percent granular
matrix, 35% chondrules, 10% troilite and 7% metal, 8% coarse
olivine, 5% coarse orthopyroxene and feldspar, plus accessory chromite.
The well-developed and preserved fusion crust shows a 3-layer
structure and averages .4 mm thick. The chondrite is very weakly
shocked, based on the strain state of olivine (S2 shock).

Key results of electron microprobe analysis (quoting number of points
analysed, mean value and 2 s.d. n-1) are: olivine (10, Fa25.8 +/- 0.2),
orthopyroxene (11, Fs21.4 +/- 0.4), kamacite (12, 0.95 +/- 0.04 wt.% Co,
6.30 +/- 0.76 wt.% Ni) and taenite (10, 0.37 +/- 0.12 wt.% Co, 29.0
+/- 4.4 wt.% Ni). The silicates show no trace of zonation within or
between grains of different sizes and textural settings. There is
minimal
apparent variation in kamacite (5.6-6.9% Ni, 0.92-0.99% Co), but within
the taenite Co declines from 0.50 to 0.30% as Ni increases from 25.8
to 31.8%. The two metal phases form composite grains in which they are
cleanly separated by simple arcuate boundaries, and the result is
considered at least an indication of a genuine variation.

Kitchener, Ontario is an unbrecciated, troilite-rich, L6 (S2) ordinary
chondrite, with a well-developed fusion crust. The petrologic grade is
assigned on the basis of indistinct margins on most chondrules, lack of
the beautiful chondrules of unequilibrated ordinary chondrites, and
the presence of coarse feldspar. The bulk of the fall resides in the
National Meteorite Collection of Canada in Ottawa. 
-- 
Matt Morgan
Mile High Meteorites
http://www.mhmeteorites.com
P.O.Box 151293
Lakewood, CO 80215-9293

----------
Archives located at:
http://www.meteoritecentral.com/list_best.html

For help, FAQ's and sub. info. visit:
http://www.meteoritecentral.com/mailing_list.html
----------