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 >>>

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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.

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.

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.

To most people the study of meteorites might perhaps seem as “hard science” a topic as one could find. Planetary geology, the formation of asteroids, the theories of chondrule creation, how meteorites heat up and break up in our atmosphere, where they fall, and what they are made of are just a few of the topics we research and ponder. So, what a delight it is to find a book that does not deal, primarily, with the composition and classification of meteorites, but rather delves deeply into their mystery, history, and allure.

Christopher uses meteorites as a vehicle to embark upon his own journey of discovery, at the same time considering the astonishing journeys they have made. While visiting some of the most famous meteorites sites in the world including Cape York, Greenland; Antarctica; the Brenham, Kansas strewnfield, and Meteor Crater, Arizona; he ponders the motives and passions of brilliant and eccentric scientists, researchers, hunters and entrepreneurs who made the study of—or the acquisition of—meteorites the pivotal moments of their lives. And he makes some significant discoveries about his own life along the way.

“We each have found ourselves lost in the dark wood, whatever we thought the true way had been or can be, but for me, in no small measure, I found the path out because it was lit at times with the passage of shooting stars. This book is an exploration of lives, including my own, caught in such light.”

The editor of Istope: A Journal of Literary Nature and Science Writing and a professor of English at Utah State University, Christopher is a literary writer in every sense of the word. His prose is unique and lyrical, full of imagery and contemplation. There is also plenty of humor and plenty of adventure, and rich portraits of characters who played critical roles in the history of space rocks.

The Fallen Sky is an intensely personal book. Christopher digs into the lore of space rocks and shooting stars and then uses what he learns about them to examine his own life. It is the most personal and most moving book about space rocks since Harvey Harlow Nininger’s great autobiography, Find a Falling Star, published in 1972 and now long out-of-print.

A beautiful and thoughtful work, The Fallen Sky belongs on the bookshelf or bedside table of everyone interested in meteorites, astronomy, the study of obsession, and the history of science.

On olivine-rich pallasites:

“The olivine, which on Earth is the gemstone peridot, seems to glow from within. Slices of pallasites look a bit like the coat of a metal leopard with green spots . . . Brenham olivine is autumnal and ethereal, like an October forest and sky in a luminist painting. The curves of metal look like sinuous paths connecting lakes seen from on high. A slice of Brenham? It’s a silver sponge that soaks up light.”

The Fallen Sky: An Intimate History of Shooting Stars by Christoper Cokinos is published by Penguin USA on July 30, 2009
Hardcover
9.25 x 6.25 in
528 pages
$27.95

The reasoning went something like this: Since god was supposed to have created the heavens, and since — of course — anything that god created had to be perfect, then claiming that stones could fall from the heavens suggest that the heavens were not perfect. And that just wouldn’t do. The official viewpoint of the Roman Catholic Church was, therefore, that meteorites could not exist. Such logical reasoning!

That all changed on the afternoon of April 26, 1803 when literally thousands of stone meteorites rained down — in bright daylight — upon farmer’s fields in the French town of l’Aigle (“the eagle”). The eminent physicist Jean Baptiste Biot was dispatched to the scene, where he collected and described numerous freshly-fallen specimens. Over the centuries, those specimens found their way into prominent collections, and I once had the pleasure of handling some of those actual pieces in the secret basement collection room of the Museum of Natural History, London. With preserved fusion crust as black as liquorice and meticulously written specimen cards (all in French and with an appropriate fountain pen flourish), those fabulous historic and history-changing rocks took me right back to the earliest days of meteorite collecting.

Well, Biot’s resulting paper, supported by scores of eyewitness accounts meant the stubborn church views eventually had to give way. And the most interesting part about this tale is that even though the Vatican’s position was that meteorites could not exist, that viewpoint did not stop them from quietly putting together one of the world’s largest collections of space rocks. Despite the official company line, they knew something was going on. Or falling down, might be more accurate.

So, what do we learn from this 19th-Century story? Try to keep an open mind? The heavens actually are not perfect? Always take the word of a French physicist over the Pope? I’ll go with three out of three on that.

Watch the skies and please check out my latest science column: “Impactites: Ghostly Footprints of Ancient Meteorite Impacts” on Geology.com