An Article In Meteorite-Times Magazine

This feature is devoted each month to one of the personalities within the meteorite community. This month we are delighted to share an interview we had with Robert Matson.


What or who got you interested in meteorites and how old were you when you got your first meteorite?


As far back as I can remember, I've had an interest in all things astronomical -- eclipses, meteor showers, comets, planets, occultations, deep space objects, even man-made satellites. I have some vague recollection of seeing the meteorite display at the Smithsonian as a child, but I considered the objects so rare and unattainable that I couldn't get very interested in them.

But then something remarkable happened -- my girlfriend's mother (later to be my mother-in-law) showed me not just one meteorite, but half a dozen one afternoon visit in the spring of 1999. I was dumbfounded! It never occurred to me that you could ~buy~ meteorites -- at least not without spending a fortune. Not two weeks later, I was holding my first two, very own meteorites at the ripe old age of 37.

 

 

 

What were those first two meteorites?

A Huckitta pallasite and a Sikhote-Alin, both purchased from Mike Farmer.

 

 

Do you still have them?

Yes, indeed!

Do you have special areas of interest that you focus on in regards to meteorites (thin sections, photography, chemistry, age dating..etc)?

Pretty much all facets of meteorites fascinate me; what's so great about these space visitors is that there's always more to learn. One particular project that has held my attention from the beginning is the experimental determination of annual meteorite fall rate based on recoveries versus area covered. As the years, square miles, and meteorites pile up, I'm converging on a pretty good figure for the average flux over the last 5000 to 10000 years. (It's higher than most people think -- by a factor of 3 or more.)

Does your Family share in your interest in meteorites?

Interest, yes, but not quite the passion. My wife, Lisa, has been on many meteorite recovery trips with me, and even has a find to her name. She probably knows more about meteorites than 99% of the population, but the "bug" hasn't bitten her like it has her mother, Elaine.

Do you have any special approaches to collecting? (Type collection, only stones, only irons, only by aesthetics, etc. or any and all that you like.)

The focus has shifted over the years. At first it was random variety, with an attempt at geographical diversity. Later, I concentrated on unequilibrated ordinary chondrites. These days it's achondrites and other rare meteorite types, though the rate of acquisition has dropped considerably due to the higher prices these specimens command.

Do you mind saying how many locations your collection represents?

Around 90 -- there are so many ways to count it, depending on whether you consider each NWA stone to be a separate "location", and whether unpaired finds from the same location count as one location. (For example, I have 9 meteorite finds from Superior Valley, California, representing at least half a dozen separate falls.)


Superior Valley 010 (26.26g, L4, S2, W2) -- June 14, 2001.

Is your collection displayed or kept in a dry box or both?

Many are displayed in Riker or membrane boxes; most are tagged and bagged with dessicants in a cool dark location.

In what ways do you use your computer for meteorites?

Where do I begin? My collection information is all stored in digital form, and of course I have Monica Grady's indispensable Catalogue of Meteorites a double-click away. Then there are all of my meteorite recovery GPS track logs, and scanned photographs of insitu finds.

I keep statistics on my hours searched at each geographical location, as well as a master Excel plot of finds versus actual field search hours. I maintain detailed databases of all California and Nevada meteorites, as these are the states in which I've done the majority of my field work.

But aside from all the bookkeeping, I also write trajectory analysis software. My first application was written to exercise the theory championed by Darryl Futrell (May he rest in peace) that tektites are the product of lunar volcanism. I ran a full range of simulations, varying the lunar ejection location,
velocity, azimuth and elevation and propagated the transfer orbits to impact. Bottom line is that the theory just doesn't work -- lunar ejecta either end up in heliocentric orbit, back on the Moon, or scattered all over the earth's surface.

My current trajectory work focuses on the Park Forest bolide, and modeling of the breakup and resulting strewn field. A lot of analysis remains to be done, but initial predictions look quite good.

How often do you hunt for meteorites?

My first meteorite hunting trip was 9/11/99, a date which is now unfortunately very easy to remember. That trip was to Lucerne Valley, inspired by papers and articles I found online by Ron Hartman, Bob Verish and others. I only spent three hours there, found a variety of little black rocks (LBRs), but no meteorites. Unfortunately, my next 7 trips to various desert locations had similar results. (Oddly enough, I later found meteorites at 5 of the 7 locations I visited in those first 8 trips!)

9th time was a charm, though, netting Silver Dry Lake 001. Today, my trip count and meteorite count both stand at 65, representing some 30,000 miles of driving and 400 hours of searching.


Silver Dry Lake 001 (218.8g, L4, S2, W2)

What is your favorite meteorite in your collection?

Tough call. Silver Dry Lake 001 will always be on my A-list. Aside from being my first find, it has a lot of character. For wow-factor, I'd have to go with the beautiful slice of Dhofar lunar meteorite I purchased from finder Norbert Classen.

What is your favorite overall if it is not the one above?

I don't have an overall favorite, but Bob Haag's Adamana "Venus" stone from Arizona, the Tucson Ring, and Esquel are probably among the top five.

What makes these of special interest?

Each is aesthetically beautiful, unique, and instantly recognizable by nearly everyone with an interest in meteorites.


This is an in situ image of Superior Valley 006 found 3/8/2001.
Mass is 78.50 grams; classification is H6, S2, W6.

What meteorites are currently on your wish list?

At some point I'd like to acquire a nice-sized (multi-gram) Martian meteorite slice. But my ultimate goal is to *find* an achondrite.

What methods have been most successful in building your collection? (Buying at shows, from dealers by mail, auctions on the web, trading... etc)

It would have to be finding them in the desert myself. The rest of my acquisitions have been through dealer websites, eBay auctions, telephone
calls to dealers, shows, and trades -- in that order.

Do you also collect related materials like impact glasses, breccias, melts, tektites, shocked fossils, native iron rocks etc?

So far, just the last on the list: a sample of josephenite from Oregon, and some nice-sized Putorano samples from John Gwilliam.

Do you prepare any of your own specimens? (cut, polish, etch, etc.)


I have a small 8" saw which I use primarily for cutting type specimens of my finds. When I polish, it's by hand with alcohol and wet-and-dry sandpaper. I've done a little bit of etching with ferric chloride, more for diagnostic testing rather than finished products.


I found this meteorite on the day that Columbia disintegrated. :-( --Rob

Have you had to take any special measures to protect them from the environment?

I live two miles from the ocean, so many irons do not do so well at my home, bagged or not. I've had decent success with sodium hydroxide dissolved in alcohol and distilled water a la Steve Schoner, but it's tedious keeping these irons "happy", so I've pretty much avoided them for the last couple years.

It's not just the irons, unfortunately. Due to seasonal rains, desert playas are nasty places for meteorites to spend much time, and much of my collection has spent hundreds if not thousands of years in this high alkali environment. Even if you cut these guys in pure alcohol, give them a good long bake-out, and bag them with plenty of dessicant, a good fraction of them still "bleed" within weeks. I've been reluctant to attempt driving off the chlorine with the NaOH treatment, as chondrites aren't as hardy as their iron breathren, and some are so porous and/or friable that such efforts might easily backfire.

Humidity/chlorine is only part of the problem. I think daily temperature swings are also rough on meteorites, just as it is on wine. Now ~there's~ an idea -- a meteorite fridge. But would you use the cabernet or chardonnay setting?


A more recent find at Superior Valley -- 307.75 grams (my largest find from California).
Analysis ongoing at UCLA.

Where do you plan to hunt next?

I have several on-going study areas that require a lot more work, particularly Lucerne Valley. It's been a very wet summer in the Mojave Desert, so I expect to see a lot of changes -- some good, some bad. I'll no doubt pay a visit this fall to my old favorite, Superior Valley, to see if anything new has been uncovered by rain runoff. Same goes for Roach Dry Lake in Nevada, where I try to stop for at least half a day any time I go to Las Vegas or Lake Mead.



These two pictures are of a fairly fresh meteorite (H5, S2, W1) find from an
undisclosed Mojave desert location; first image is insitu;
the second of me with this find was taken by Nick Gessler.

 

My longer range plans are to return to northern Nevada for a multi-day trip, and pay a visit to Park Forest to do some model validation work. Ultimately I'd like to plan an out-of-the-country expedition to a place like Oman, or (if I'm really lucky) take part in one of the Antarctic meteorite team searches (e.g. ANSMET).