Nevada Meteorite Picture of the Day

Discover the Solar System - right here in the Nevada desert! Each day a different image or photograph of a NEVADA meteorite will be featured, along with a brief explanation written by a meteorite-recovery expert.

2005 March 31
See Explanation.  Clicking on the image will download
 the highest resolution version available.


Name of Nevada Meteorite: Alkali 003 (LL6 S4 W2) - provisional nomenclature
Credit: Image by Robert Verish, taken 2005 March 26th.

Explanation:

The above image depicts a close-up of the cut surface on a chondritic stone fragment that was found on August 18, 2003. This specimen was cut in order to extract a "type specimen" per Meteoritical Society requirements. This fragment was later found to be physically paired to another, smaller meteorite fragment that was found EARLIER on December 1st, 2002.

Four years earlier on July 20th 1998, the 8th Nevada meteorite (no known as "Alkali") was found here by Nick Gessler. During those intervening years many other experienced searchers have tried in vain to make another meteorite find. In fact, I led small teams of experienced meteorite-recovery experts on two earlier attempts and had no success, as well. But after making some observations at other dry lakes, about how the prevailing wind direction would be very different from one season to the next, I decided to return with another team (2002), as soon as possible, before the snow would start to fall.

Well, we got there a day too late. Most of the snow had melted, but my 2002 Team had to deal with a "dry" lake that was under water and a very muddy shoreline. So, it became imperative for me to chose only that portion of the shoreline that was the most promising. By having studied the history of the weather patterns and prevailing wind direction for this area, I was able to narrow down this "most promising" area to just a 1 mile stretch of shoreline. We focused our search along this stretch of shoreline.

After only a few hours, we found "an out-of-place stone" on a broad area of widely scattered pebbles and small cobbles that had a sharp demarcation, which appeared to have been at one time a shoreline. The "out-of-place" rock was a fragment of a chondritic stone meteorite, now known as Alkali 002 (H5).

We found four more fragments, all within a narrow area, or "accumulation zone". I was able to "physically pair" all four of the larger fragments. But this one, small remaining fragment caused me to give it a very close look. It was then that I recognized it as being different from all the other fragments This one small fragment was later classified as an LL6 impact breccia, which is obviously unpaired to the previous finds from Alkali.

Moving forward to Aug 18th 2003, my 2003 Team had much better weather conditions. Soon after bringing the 2003 Team to the same previous location, we immediately found another fragment. It was larger than the earlier found (2002) fragment. I was able to physically attach the earlier found fragment with this newly found piece, making it an LL6 meteorite, as well. Now started a debate as to how did this fragment get to this location. We were unaminous in our agreement that this fragment wasn't at this location 10 months earlier. There was no way that we would have missed it. We have this same discussion at every stranding surface that we return to and find "new" meteorites. The debate continues...

Some more IMAGES:
Alkali (H6 S2 W2)
Alkali 002 (prov.) (H5 S3 W3) - All 4 fragments side-by-side.
Close-up of the "A" fragment of Alkali 002 (prov.) "in-situ"
Close-up of a cut surface on Alkali 002 (prov.) (H5 S3 W3)
"Alkali 003" There was a 5th fragment (8 grams) that didn't physically fit to this puzzle. It has been classified as an LL6 impact breccia, and is unpaired to the other 4 fragments. This "5th fragment" would then become "Alkali 003".
UPDATE: On a subsequent trip (2003Aug18) another fragment was found. This 27.7g piece was able to be physically paired to the original 8g find. Both of these fragments will form the singular stone that will be known as "Alkali 003".

(Scale is 1 centimeter cube.)

For Reference:

Alkali [Lake]
3752'N 11724'W
Esmeralda County, Nevada, USA
Found 1998 July 20
Ordinary chondrite (H6)
Two stones, weighing a total of 30.47 g, were recovered two miles apart by Nicholas Gessler from the dry surface of Alkali Lake.
Mineralogy and classification (A. Rubin, UCLA) olivine, Fa 19.3; shock stage, S2; weathering grade,W2.
Specimens: type specimen, 5.4 g, UCLA; main mass, Gessler.

Alkali 002
[Nomenclature pending approval]
Esmeralda County, Nevada, USA
Found 2002 December 01
Ordinary chondrite (H5)
One (reconstructed) stone, from 4 physically-paired fragments, weighing a total of 163.1 g, were recovered ~20 meters apart along the shoreline of Alkali Dry Lake. [Within this same ~80 square meter area, a 5th fragment (7.75 grams) and a 6th "paired" fragment (27.7 grams, TKW=35.45g) was found, as well, but has been subsequently identified as being an LL6 breccia (Alkali 003) and is not paired to any previously found stone from Alkali Dry Lake.]
Mineralogy and classification (A. Rubin, UCLA) olivine, Fa 17.7; shock stage, S3; weathering grade, W3.
Specimens: type specimen, 26.1 g, UCLA; main mass, Verish(Meteorite-Recovery Lab, P.O. Box 237, Sunland, CA 91041).

The next "Picture of the Day": will be next month.


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Authors & editors: Robert Verish (Meteorite-Recovery Lab)