Meteorite hunting in Franconia, AZ

This guest article was written by local meteorite hunter Eric Rasmussen by request from BCMS Director Rhonda Stroud.  Meteorite hunting can be a great way to have fun and start or expand a collection. However, before hunting for meteorites, make sure to check local laws regarding meteorite hunting, land ownership, and property access rules (public as well as private). Always respect the law, the land, and leave no trace. For a map of Arizona land ownership, see http://gis.azland.gov/webapps/parcel/.

Rasmussen here describes his experiences hunting in a dense collection area of northeastern Arizona which encompasses, among others, the Franconia (H5 chondrite) strewn field, and discusses finding pieces of the Sacramento Wash 005 (H-metal) meteorite. To date, 44 distinct meteorites have been classified from this same area. Sacramento Wash 005 was classified in 2008 by Buseck Center Deputy Director Dr. Devin Schrader; click here to read about some of his research on this meteorite. The opinions and information expressed are the author’s own, and do not represent those of the Buseck Center for Meteorite Studies.

Over  the weekend of October 28 – 30, 2022, five of us planned to hunt the Franconia meteorite strewn field north of Lake Havasu City. However, an October 24 meteorite fall over Northwestern Arizona (American Meteor Society event 7315-2022) changed some of our plans. Three of the group decided to hunt the possible new fall in the White Hills area north of Kingman, AZ. That left just two of us to hunt the Franconia strewn field.

Unfortunately for me, I missed the heyday of meteorite hunting in the Franconia area by about seven years. My first meteorite hunt there was in 2016. During that first hunt, I found two small chondrites in the very northern end of the strewn field with my new Gold Bug 2 metal detector. Several of my return visits resulted in no meteorite finds, as I later learned that I was hunting too far west of the strewn field. My knowledge of the area increased thanks to other more experienced meteorite hunters so now I feel more confident in my trips there.

Although each year that goes by it seems that chondrites are harder and harder to find at Franconia, it is still great to get out in the open high desert looking for space rocks. During different trips to Franconia, I have been followed by a wild mule, seen a snake drinking freshly fallen rainwater from a hole in a basalt rock and come across a desert tortoise slowly living its life.

On Friday we arrived at Franconia around 11:30 AM. The heavy rains in Arizona during September and October had really washed out the road where you enter the strewn field. There were a large grader and a front-end loader working on the road when we arrived, and they had made it a bit easier for us to get where we needed to be. We were out in the desert swinging our metal detectors before noon.

Meteorite detecting in the Franconia area is not easy. With almost every swing of your metal detector you will hear an audible signal return. The majority of signal returns are caused by “hot rocks”. These hot rocks are rocks that possess just enough magnetic minerals  to set off your metal detector. There are also areas of magnetic black sand (iron oxide) that can generate a signal. Then, there are the 50-caliber bullets and shell casings left by the World War II-era Army Anti-Aircraft training facility in the area. Many of the meteorites in this strewn field are Franconia (H5) chondrites, so given their  high metallic iron content, they will trigger a good audible signal from the metal detector. After hunting at Franconia for a while, you learn to recognize  the different audible returns you hear from your metal detector – this helps you to determine which signals you will investigate.

About one and a half hours into our meteorite hunt, I was rewarded by a strong audible signal, which ended up being a small iron sulfide meteorite (a piece of the Sacramento Wash 005 meteorite, learn more here). About an hour after that, my partner found his first meteorite, which was also an iron sulfide meteorite. I found two more iron sulfides that afternoon before calling it a day.

On Saturday we got to the collection area about 9:30 AM and began Day Two of our meteorite hunt. We had researched the strewn field map Friday evening and decided to hunt a valley where many chondrites had been found in the past. Early in the afternoon, I finally made our first find of the day: Another small iron sulfide meteorite. This little meteorite was interesting because it had a small round hole on one edge where a sulfide bleb may have been located sometime in the distant past. During Day Two, we were in the strewn field longer but were having less success. Around 4:00 PM, as we were headed back to our cars, my partner found a small chondrite on top of a ridge.

I had been texting our friends who were searching for the new fall northeast of us. They and several others had put in lots of time, but no freshly fallen meteorites had been found. We headed back to the Hotel in Lake Havasu City, had a great dinner and then rested our tired bodies from a full day of hunting meteorites in the desert. Sunday morning, we headed back to Phoenix with our newly found space rocks.

This guest article was written by meteorite hunter Eric Rasmussen.