An Article In Meteorite Times Magazine
by Robert Verish
NOT another article about "Gold Basin AREA" Meteorites!
Last month's articles on "Gold Basin Area Meteorites" generated a lot of discussion and letters to the editor.
Most people commented that they would like to see images of these "Gold Basin
(L6) stones", while others were curious "where in the strewn field were they
found". But others raised objections to Gold Basin being reclassified to a
"L4-6" when no stone has been shown to consist of breccia clasts of L4 thru L6.
"...no evidence for brecciation", let alone a genomict/polymict breccia.
As a result, my editor requested that I should write another article and
attempt to answer some of these questions. But I will be disappointing my
editor, because I am going to decline that suggestion. Instead, I am going to
defer to Jim Kreigh, the finder of the Gold Basin Meteorite, who's study of that
strewn field is still on-going. This is what is known as "professional
protocol", and all field workers and even collectors have to be sensitive to
these issues. And this is what I have been espousing ever since I first started
writing about Gold Basin back in 1998 - "contact Jim Kriegh", and tell him the
weights of your finds. And all I have been doing since then (whether at Gold
Basin or elsewhere), is just that -
Recording what I find, and Reporting those findings.
Yes! The purpose of this web page is to report my personal findings from the field. But, there's another "protocol" (this one for publications) and it recommends that only approved nomenclature be used. Donald O'Keffee's Hualapai Wash and Gold Basin are PRESENTLY the only names approved by the Nomenclature Committee (while all other L6 stones are to be considered as "Gold Basin (L6)" until deemed otherwise). And I have deferred from writing about Gold Basin. So, until the Gold Basin (L6) "issue" is resolved, all Gold Basin Area meteorite questions are the purview of Jim Kriegh and the University of Arizona. And besides, to attempt to answer some of the questions that have been raised would require access to data that is proprietary to Jim Kriegh's on-going study. So, the reporting of that data should come from that study group.
That's not to say that Jim Kriegh isn't invited to be a co-author on this web page to present any of his new findings. In fact, I communicate with Jim regularly and he is quite aware that all of my field records and specimens are at his disposal. And there are still available at UCLA "classified" type specimens (of former "Hualapai Wash" stones) that Tim Jull (of the Univ.of Ariz) can Carbon-14 age-date.
But, in the meanwhile, my interest in the Gold Basin strewn field has been satisfied by the lastest published paper in the 2001 August MAPS (Kring D. F. et al. (2001) Meteorit. Planet. Sci., 36, p1058) in which the following facts have been documented:
(1) "...(White Elephant) is part of a relatively large object [meteoroid]
that also fragmented when it fell. Therefore, the Gold Basin area could be
composed of [at least] two overlapping ordinary chondrite strewn fields." No
surprise, but now it's official. (AND there is anecdotal information that a
certain Gold Basin researcher has seen (in thin section) some stones that GRADE
from L4 to L6!!)
(2) "evidence of [brecciation] is not visible in thin section". If it isn't evident in thin section, it will never be apparent in hand specimen.
Because of "(1)", I can now add the Gold Basin Area to the ever-growing list of "overlapping strewn fields" that are being found throughout the Mojave Desert. And because of "(2)", there is now evidence for "gradational thermal metamorphism". But it will take time for that concept to be accepted.
And finally, Jim Kriegh has asked me to pass this along - that he is still tabulating the mass for all the Gold Basin finds and would appreciate receiving reports from finders regarding the mass of their finds. He said that reports from searches along the periphery of the strewn field would be of the greatest interest. That is why I am concentrating my Meteorite-Recovery Team's efforts north (in Nevada) and south (in the Red Dry Lake Area). No "Gold Basin (L6)" finds have been made in these areas, yet. (I will be reporting on Red Dry Lake in a future issue, but if you should make a find there, please contact me, and I can assign for your find the next Red Dry Lake "Find Number" - presently that number is "024", but it is rising. Art Jones and I recently visited there and we added 2 more to the Red Dry Lake total.)
But in the meanwhile, if you should cut into a "Gold Basin" stone and find that it looks like the interiors of the stone shown in the following images, please contact Jim Kriegh (JKriegh@msn.com) :
Above is a sample from Bud Eisler of the recently found 3.6kg "fresh" chondrite from the "Gold Basin AREA". It has been submitted for analysis, but preliminary results indicate that it [probably] is an L6.
Above is a 160g cut individual from the "Gold Basin AREA". It hasn't been analyzed , but preliminary results indicate that it [will be] an L6. It will not be submitted for analysis, because the finder and the find location can not be verified. I will have no need to retain this stone, so it is available to anyone interested in a Hualapai Wash "look-alike".
The "Original find by Donald O'Keeffe", referred to in the image, is the "Hualapai Wash" of Meteoritical Bulletin #85. It was classified by UCLA as being "L6", and is still an "approved" name:
These "Gold Basin AREA stonys" were classified and the following names were submitted to the Nomenclature Committee for approval, but have been put on hold:
And the following specimens have been classified, as well:
All of the above stones "look like Gold Basin (L4)", when judging them only from their weathered exterior. It is no wonder then, that before these stones were cut, they were all "deemed" by collectors and dealers as being "Gold Basin (L4)"!
Because of White Elephant and Hualapai Wash meteorites, it is abundantly clear that no UNCLASSIFIED stone can be called, "Gold Basin (L4)", with any certainty.
Usage of the term "Gold Basin AREA meteorite" is now considered more appropriate.
For for more information, please contact me by email: Bolide*chaser