Meteorites in Oro Valley: An Historical Collection

This is a follow-up article on Jim Kriegh, founding father of Oro Valley and the Oro Valley Historical Society. The Oro Valley Historical Society typically focuses on local history but in this article, we feature history that fell to earth 15,000 years ago! This piece is written by long-time friend of Kriegh’s, Twink Monrad. Twink was Jim’s neighbor and metal detecting buddy and she is a life-time member of the Oro Valley Historical Society.

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Meteorites in Oro Valley: An Historical Collection

In 1995 Jim Kriegh, his friend John Blennert and I belonged to the Desert Gold Diggers, a local club whose members hunt for gold in Arizona. Dr. David Kring, a meteoriticist and planetary scientist from the University of Arizona, spoke at one of the club’s meetings and encouraged those who used metal detectors to keep an eye and ear out for meteorites generally small nondescript objects that look nothing like gold. Jim paid good attention because while searching for gold in the Santa Rita Mountains he found a rock which turned out to be a meteorite, later named the Greaterville meteorite.

Jim and John also searched for gold far north of Tucson in the northwestern corner of the state, the Gold Basin Area. While there, they kept hearing rocks which sounded like gold on their metal detectors but did not look like gold. Jim was steadfast in his belief that they were heavier than Earth rocks for their size and the sound was too good. Jim took some samples to Dr. Kring who identified them as stone meteorites.

I was invited along on the next trip to Gold Basin. We went with our camping equipment and most important, a generator and power saw to cut any likely meteorite specimens that we might find. The first day John and Jim came back to camp with numerous rocks while I was still learning how to use my detector! Several times a day we would bring back rocks which made noise and were magnetic. Jim sawed them open. Some were meteorite specimens and some were not. As the week progressed, we became more aware of how the meteorites looked and soon we did not need to saw them open to identify them. We took our finds to Dr. Kring at UA. It seemed Jim had discovered a rare strewn field.

Now our real work began. As a civil engineer, Jim could mark them on a topographic map with accuracy. GPS units were not as common as now so we did it all by hand. We prepared an index card for each meteorite with notes on gram weight, date, location but it soon became apparent that there would be too many, so Jim began numbering them by groups. A further request was that we would tell no one about the find so that University could properly study the area for two years. We three became a team to assist the University of Arizona. After UA finished the study, the meteorites were named Gold Basin by the international nomenclature committee.

We found over 2,000 meteorites, and expanded the strewn field boundaries to five miles by fifteen miles! It is not known how large the field really is. Meteorite composition tests show that these are L4 stone meteorites which fell approximately 15,000 years ago near the end of the Ice Age. We each found a couple of different meteorites in this field which represented different falls at different times in addition to the original Gold Basin meteorite. [ Editor’s note: Sky and Telescope Magazine reported the following in July 1998: Isotopic studies indicate a terrestrial age between 20,000 and 25,000 years, making the Gold Basin the oldest surviving strewn field outside Antarctica.]

I have Jim’s original map which I treasure and had laminated.  It was a very fun adventure for us all and especially as the find was announced at the 1998 Tucson Gem and Mineral Show.  We literally felt like we had 200 new friends as everyone in the meteorite world, hunters, scientists, authors and collectors wanted to meet the U of A civil engineering professor who “accidentally” discovered a major meteorite field.  Jim has been given worldwide credit for showing that the average person, women and men, can find a new hobby of either discovering new meteorite finds or just finding meteorites at newly discovered fields.  Most of the meteorites that we found during the first two years were returned to us after the U of A studied and documented each one, some they kept and a few went to the Smithsonian for study.

Searching for meteorites is fun and may also make valuable contributions to science as did Jim’s discovery at Gold Basin. Meteorites and other objects from space have been important throughout history for those who watched the night sky. We are fortunate that Jim’s meteorite collection is available for the Oro Valley community to enjoy. 

 [Editor’s note: On December 17, 2007, according to Jim’s wishes the Kriegh Family Trust donated a part of Jim’s meteorite collection to the Oro Valley Historical Society (OVHS). OVHS has periodically displayed this collection at the OV branch of the Pima County Library and at the Pusch House Museum at Steam Pump Ranch. It also has been used for school and OV Parks and Recreation activities.] 

Twink Monrad

For additional information about the Gold Basin find see this link to an interview with Jim Kriegh by Paul Harris of Meteorite Times Magazine and one relating Twink’s experience at Gold Basin

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WE WANT YOU! The Oro Valley Historical Society is a 501 (c) (3) non-profit volunteer organization, whose mission is “To promote research, preservation, education, and dissemination of historical information related to the greater Oro Valley area”. We invite you to become a member or volunteer. Visit us at ovhistory.org and help keep Oro Valley history alive! We are currently looking for enthusiastic volunteers who are interested in becoming docents at the Pusch House museum and for Steam Pump Ranch tours. Training sessions are being scheduled for the fall season. We hope to hear from you. Contact: Teri at tcolmar@comcast.net