A Sikhote-Alin Meteorite Discovery: The Missing Link

The February, 1947 fall of the Sikhote-Alin iron in a remote part of eastern Siberia was, by far, the largest recorded meteorite event in history. While Campo del Cielo (Argentina), Muonionalusta (Sweden), and Gibeon (Namibia) may possibly have deposited more meteorites in terms of sheer tonnage, they all took place in prehistoric times. If those events were even seen by early humans, the witnesses lived thousands of years before the advent of writing and so no records exist.

A 137.7-gram Sikhote-Alin meteorite "individual" displaying characteristic regmaglypts (thumbprints)

The eminent Russian meteoriticist, E. L. Krinov, visited the fall site and recovered numerous specimens, which ended up in the Russian Academy of Sciences. Some of his team’s finds were lying on pedestals of snow, never having actually touched the ground, and displayed a blue/grey fusion crust. Krinov wrote an entire book about Sikhote-Alin, but it has, sadly, never been translated into English.

Scientists, and later, collectors, noted that there are two distinctive types of Sikhote-Alin meteorites: shrapnel and individuals. Shrapnel fragments are the result of in-flight explosions of large masses which produced twisted, angular shards reminiscent of bomb case shrapnel, hence their name. Individuals flew though the air as autonomous entities and ablation in the atmosphere caused them to acquire remarkable and sculptural shapes. Individuals frequently display regmaglypts, which are thumbprint-like indentations caused by surface melting.

One face of the 2,785-gram Sikhote-Alin "Missing Link" displays all the typical qualities of shrapnel

One of the intriguing questions about the Sikhote-Alin fall is where and when did the shrapnel-producing detonations take place. After examining a recent acquisition which we call “The Missing Link,” we are able to put forward a hypothesis. Until now, Sikhote-Alins fell into one of two categories, but a recently discovered shrapnel/individual hybrid demonstrates that there are, in fact, three types of Sikhote-Alin meteorite.

The piece in question weighs 2,785 grams and is roughly pentagonal in shape. One large face and two edges are typical of shrapnel specimens: their surfaces are torn and distressed; one face and one edge, remarkably enough, bear the obvious characteristics of individuals in that they are covered with large, oblong regmaglypts.

The exterior face of "The Missing Link" exhibits large and well-formed regmaglypts

The pioneering American meteoriticist H.H. Nininger noted a correlation between the size of regmaglypts and the size of the individuals upon which they appear: the larger the mass, the larger the thumbprints on its surface. The regmaglypts on our shrapnel/individual hybrid are extremely large: one of them is 32.5 mm in length. This tells us that the original meteoroid—prior to fragmentation—was massive. This fascinating meteorite also suggests that the in-flight fragmentation which formed the Sikhote-Alin shrapnel pieces occurred relatively late, and probably close to the ground. It is also interesting to note that shrapnel specimens are associated with the 100+ craters in the Sikhote-Alin strewnfield. While at first glance this suggests that shrapnel was formed by explosive cratering events, some shrapnel specimens display tiny impact pits, which must have been caused by the in-flight impacts of smaller meteorites.

The regmaglypts on our 2.785-kg specimen took time to form. The original mass needed to heat up and melt during flight, before finally exploding. So, what we are looking at here is a surviving piece of the exterior of one of the largest, or perhaps the largest original masses of Sikhote-Alin. The oversize, well-formed regmaglypts demonstrate that it was once part of a very large individual, while its twisted shrapnel-like areas show that it also fragmented in flight.

Detail of regmaglypts on the 2,785-gram "Missing Link"

Sikhote-Alin is my favorite meteorite, and I have handled literally thousands of specimens over the past decade and a half. “The Missing Link” is the single most intriguing piece out of all of them, and in the words of Aerolite’s operations manager and staff geologist: “Well, that’s just cool!”

Learn more about the Sikhote-Alin witnessed fall >>>

Photographs by Suzanne Morrison © Aerolite Meteorites LLC
All rights reserved. No reproduction without written permission.
The owner strictly enforces intellectual property rights.

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The Millbillillie Meteorite: Part of the Asteroid Vesta?

The Millbillillie eucrite belongs to one of the rarest meteorite types. It is part of the HED group, which also includes howardites and diogenites. Eucrites are achondrites, meaning “not chondrites,” so they are lacking in chondrules—the small, spherical, pre-solar grains that give the common chondrites their name. Millbillillie meteorites are volcanic rock from other worlds, and are comprised largely of silicate minerals. They are light in weight—similar in feel to terrestrial pumice—and are among those extremely uncommon meteorites which contain no iron, and show no attraction to a magnet. As such, they are less dense than the majority of meteorites and even a modest specimen of 6 or 7 grams can still be enjoyed and studied without magnification.

Remarkably well defined flowlines on a Millbillillie meteorite

Millbillillies typically exhibit a dazzling color combination: black fusion crust mixed with bright orange Australian desert soil which adhered to the crust, producing a visual contrast of unique and striking beauty.

This 17.5-gram Millbillillie displays abundant flowlines and a glossy, black fusion crust

The Millbillillie fall occurred in October of 1960, and was witnessed by only two men, near the town of Wiluna in Western Australia. It was ten years until the first stone was found. These intriguing space rocks often exhibit distinct orientation, glossy fusion crust, contraction cracks, rollover lips, and some of the most highly defined flowlines of any meteorite.

This full slice of the Millbillillie eucrite shows its unusual internal structure which, unlike most meteorites, is devoid of iron

Some meteoriticists believe that the HED group meteorites may have come to us from the large asteroid Vesta which was discovered in 1807 by the German astronomer Olbers. With a diameter of more than 500 km, Vesta is the second-largest body in the Asteroid Belt. If these alluring space rocks do, in fact, count Vesta as their parent body then they are among a tiny number of meteorites—along with lunars and martians—with a specific known point of origin.

See other examples of the Millbillillie meteorite >>>

Photographs by Suzanne Morrison © Aerolite Meteorites LLC
All rights reserved. No reproduction without written permission.
The owner strictly enforces intellectual property rights.

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Learn About Meteorites: Rollover Lips

When falling through our atmosphere on the way to an impact with the Earth, most meteorites spin and tumble, often acquiring the interesting sculptural shapes. A very few maintain a fixed orientation towards our planet’s surface. Heat ablation may cause those meteorites to acquire a conical, dome, or shield-shape, reminiscent of the heat shield on the Mercury, Gemini and Apollo space mission capsules and such meteorites are described as being oriented.

Oriented meteorites typically also display a flat or concave trailing edge, and sometimes a rollover lip, where molten material has accumulated on the reverse side. The characteristics of oriented meteorites were studied by rocket ship designers. Oriented meteorites are very rare, and highly prized by collectors, as are rollover lips—a remarkable feature unique to space rocks.

Detail of a rollover lip on a Gao-Guenie stone meteorite

Learn more about the Gao-Guenie meteorite >>>

Delicate rollover lip and flowlines on a rare Millbillillie eucrite meteorite from Australia

Learn more about the Millbillillie meteorite >>>

Very well defined rollover lip on a 27-gram Sikhote-Alin iron meteorite

Learn more about the Sikhote-Alin meteorite >>> 

Photographs by Suzanne Morrison and Geoffrey Notkin © Aerolite Meteorites LLC
No reproduction without written permission. All rights reserved.


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Meteorite Hunting, The Book

On February 1, 2011, my new book, Meteorite Hunting: How To Find Treasure From Space was published. We were eager to have it ready for the 2011 Tucson gem and mineral shows, so I did the actual writing in record time, but it was the product of about fifteen years of work.

In the Acknowledgements section, I wrote that I was thanking the people who not only “helped directly with the book, but also those who helped me gain the knowledge and experience that I would need in order to write it.” My view is that if you’re writing a how-guide to something, you really need to know your subject. It has been seventeen years since I found my first meteorite, and one of the remarkable things about my work is I am always learning new things, developing new techniques and hunting strategies, testing new equipment, and gathering additional knowledge about the strange and fascinating world of meteorites. If I had written Meteorite Hunting even a year earlier, it would have not been the book that it is. Our successes in the field while filming Meteorite Men Season Two added to its content, because we had unique experiences while hunting for meteorites north of the Arctic Circle in Sweden and in the Australian Outback, and also had the extraordinary pleasure of pitching our tents on the floor of Chile’s mangificent Monturaqui meteorite crater.

"Meteorite Hunting" was published Feb. 1, 2011

My friend Chris Cokinos, author of my favorite meteorite book The Fallen Sky, did me the great honor of writing the Introduction, and astronomer and asteroid specialist Dr. Larry Lebofsky and his wife Nancy, carried out a stellar job as editors. My Meteorite Men co-host, Steve Arnold, read the manuscript and made helfpul comments, as did my researcher Katherine Rambo, and my great friend Dr. Art Ehlmann, Curator Emeritus of the Oscar E. Monnig Meteorite Gallery in Fort Worth, Texas. So, I did call in some heavyweight intellects to assist, and Meteorite Hunting is the best we could make it.

A 468-gram iron meteorite found near the Henbury Craters in Australia

The book features many never-before-seen photographs from the first and second seasons of Meteorite Men. For the past couple of years I’ve been putting aside some of the best location and expedition photos for use in the book. I wanted to save something special for the new work, instead of reprinting photos that viewers and enthusiasts had already seen in other publications.

From Chapter 14
Excavating Meteorites and Documenting Finds

When Steve and I were north of the Arctic Circle in Sweden hunting the Muonionalusta strewnfield, we found a beautiful 30.4-kilogram (67-pound) iron at a depth of about 1 1/2 meters. The meteorite had been transported by a long-vanished glacier and had been deposited in the terminal moraine—unsorted debris dropped as an ice sheet melts and recedes. The iron was securely wedged under a boulder that had also been dropped by the glacier. This find proved that our pulse induction detector could, indeed, see right though large rocks. It also proved that sometimes there is no substitute for hard manual labor. Our permit to hunt at the site specified that we were not allowed to use mechanized vehicles in the forest, so we had to dig the iron by hand. The combined efforts of our four-person team were not sufficient to shift the boulder, which easily weighed several hundred pounds. Sometimes meteorite recovery is all about determination, and there was no way we were leaving that marvelous specimen in the ground. After several strategy discussions, and several hours of experimentation, we greatly expanded the size of hole, dug around the boulder, and under it, until we were able to dislodge the trapped meteorite by having our friend and colleague Carin Österburg jump up and down on it until it worked loose.

Every expedition is different and every challenge requires a new solution. Persistence pays off and, once in a while, brute force wins out.

Meteorite Hunting is 100 pages with full color throughout. It features 100 exclusive photographs, illustrations and diagrams, and was published by Aerolite Meteorites LLC, in Tucson, Arizona. Copies can be ordered safely and easily, online at www.meteoritehunters.tv or by calling the Aerolite offices at 888 SKY ROXX or 520 742 3333.

Watch the skies!

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The Famous Allison Allende Meteorite, A Rare Carbonaceous Chondrite, Finds A New Home

In 1969, five year-old Vicki Allison was living with her American missionary parents in an old adobe home in Chihuahua, Mexico, on the eastern edge of the Sierra Madre mountains.

Around 1 am on the morning of February 8, the family was awakened by a bright light and shaking. The shutters flew open and the night was illuminated by a tremendous fireball, followed by a loud boom. “It was almost like high noon,” Vicki recalls. Vicki remembers her father getting a radio or news report, of some kind, about where the impact site might be. The family piled in their van and drove 60 or 70 miles, which took several hours.

family

The Allison family in Mexico, around the time of the Allende fireball

Shortly after daybreak they arrived at an open field, where several locals were wandering around in a daze. The meteor had exploded in the air and showered the area with multiple pieces, but nobody yet knew exactly what had happened. Mr. Allison saw an odd looking rock on the ground, and “knew it was something unusual,” Vicki remembers. He carried it to the van, and put it in the back.

The family later returned to the United States, and the “unusual rock” was given to Vicki. It was used as a doorstop for many years, until Vicki’s brother saw a show about meteorites on the Discovery Channel and decided to have the Mexican rock examined.

alllison-allende

The Allison Allende carbonaceous chondrite (CV3.2) fell to earth on February 8, 1969 in Chihuahua, Mexico. Specimen weight is 4,467 grams, making it one of the largest of its type offered for private sale. As the stone was picked up immediately after the fall it still exhibits a fresh fusion crust.

The owners contacted Aerolite Meteorites who offered to work with the family and find a good home for this important meteorite. The Allison Allende was a featured exhibit during the 2008 Tucson gem and mineral shows. It was recently purchased by a private collector in the United States and can look forward to a brighter furture than its previous life as a doorstop.

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New Meteorite Men Television Series In Production

Following the success of the one-hour pilot, which has aired about twenty times since its premiere during May of 2009, Science Channel has ordered a new series of Meteorite Men episodes.

The new series of one-hour science/adventure programs will continue to co-star meteorite hunters Steve Arnold and Geoff Notkin as they search for rare and valuable rocks from space. Eric Schotz and Ruth Rivin return as executive producers for LMNO Productions of Encino, California, and Bob Melisso will continue on a supervising producer. Sonya Bourn and Kathy Williamson joined the production team in August.

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The cast and crew of Meteorite Men on location in Kiowa County, Kansas, filming the pilot in early October, 2008

Pre-production work is already underway at some top secret sites and there will be some surprises in store for viewers in the new episodes. The new series of Meteorite Men will air in 2010 on the Science Channel.

Co-host Geoff Notkin will be writing a behind-the-scenes “Making of Meteorite Men TV Diary” as part of his daily science blog, The Logical Lizard, for TucsonCitizen.com.

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