The Whetstone Mountains Meteorite
- under construction -
I will be updating this over the next few days.
Pictured is the first stone recovered and is held by Jack Schrader
Name: Whetstone Mountains
Classification: H5 Chondrite (breccia)
Witnessed fall: June 23, 2009 at 9:22 p.m. MST
Location: Arizona, USA
[location information to be withheld until publication in MAPS]
TKW: 3,080 grams
History:
A bright fireball with detonations and rumblings was observed by many witnesses. Carl Hergenrother estimated
magnitude -11 fireball that created shadows, lasted for at least ~2
seconds moving from the southeast part of the sky to the east and
downward.
Part of the path was recorded by the
All-Sky camera at the UA-Multiple-Mirror Telescope facility on Mt.
Hopkins and a security camera in Marana, AZ.
Jack
L. Schrader interviewed eye-witnesses and recovered the first 155.86 g
stone on the surface of the high desert less than 45 hours after the
fall. Within a month of its fall, additional stones were found by:
Chuck Schrader, Shauna Russell, Robert Ward, Todd Parker, and Mike
Farmer.
Physical characteristics:
Total known mass as of March 10, 2010 is 3080 grams among 22 stones and several fragments. Several were recovered as intact individuals with complete fusion crust. Some
stones exhibit regmaglypts. Fusion crust is fresh, matte black. One
stone exhibits a fusion crust with a reddish hue (not oxidation) and
others contain a few “bluish” spots.
Well defined chondrules range in size from 200-700 microns in diameter with porphyritic olivine and pyroxene chondrules being most abundant. Metal grains up to 800 microns and troilite up to 300 microns in size occur between chondrules in approximately 1:1 proportion.
Many metal grains exhibit fingerlike intergrowth of kamacite and taenite. Mg-bearing phosphates 100 x 200 microns occur between chondrules. A crushed texture is observed that corresponds to a lighter lithology in a darker groundmass. Shock veins are visible in the hand specimen.
There are two chromite-rich clasts 350 microns wide.
Mineral compositions and geochemistry:
D. H. Hill (UAz) EMP: Olivine (Fa 18.82% ± 0.25); pyroxene (Fs 16.56% ± 0.49; Wo 1.77% ± 1.7); kamacite (Ni 6.71% ± 0.28; Co 0.49% ± 0.03), taenite (26% Ni and ~40 % Ni (tetrataenite?); phosphates are mostly Mg-rich with a few Cl-bearing.
Classification:
Ordinary chondrite (H5) breccia; W0
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This is one of the most important meteorites that have fell in the United States, and the first witnessed fall recovered in Arizona in 97 years.
The first samples were recovered in an amazing 44 hours and 56 minutes and the recovery of the stones recorded in the most professional and thorough search for a fall since the days of H.H. Nininger.
The documentation of the stones set a benchmark for future falls.
Below are a few pictures from the MAG meeting where Jack spoke about the recovery of this fall.
(http://www.meteoriteassociationofgeorgia.org)
Here is link to video captured of the fall.
Security camera footage:
http://www.fallingrocks.com/Video/whetstone/whetstone.htm
