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   Are you ready to listen to a "meteorite man"? Then you'll love to hear Dave Holden speak! As a member of The Meteoritical Society, he promotes the study of extraterrestrial materials, including meteorites and space mission returned samples, and their history. Through conscienctious collection, David has had the opportunity to work with documentation and study pieces which include meteorites, cosmic dust, asteroids and comets, pieces of natural satellites, planets, impacts, and the samples from the very origins of the Solar System! Dave will join us this year bringing with him some of the most precious Sky Stones you'll ever see. Among them will be the rare, amazing and beautiful. Would like like to learn more about some of them? Then tune in...  Campo del Cielo: When the the Campo del Cielo (Field of the Sky) Meteorite was first discovered on a desolate plain in Argentina, native Indians correctly believed it to be a gift from the heavens. As Europeans began their exploration of the new lands, they heard of the legend and, in 1576, a Spanish governor sent an expedition out to retrieve a piece of this huge iron mass known he referred to as "Maison de Fierro" (Table of Iron). From there, no further records of Campo Del Cielo meteorites exist until nearly 200 years later when the Spanish returned once again - believing the find to be silver. However, when they smelted the material - they found only iron. At this time, they dug out a specimen which may have weighed as much as 18 tons and could have been the legendary Meson de Fierro - but apparently it disappeared. Early in the nineteenth century, more iron pieces were found in the area which may have belonged to the original Campo del Cielo Meteorite fall. By the 1900's, even more pieces had been found, yet the mysterious Meson de Fierro still remained elusive. In 1992, the legendary "Meteorite Man" - Robert Haag - recovered a 37 ton meteorite from the area and still remains in Argentina today. Most Campo del Cielo meteorites available to collectors come from the area of 12 small craters that range between 78 and 56 meters wide and 5 meters deep which in the southwestern part of the original fall field. By carbon dating bits of charred wood found in the craters, scientist believe the fall date of Campo del Cielo to have been between 3950 to 5800 years ago. The majority of the Campo iron meteorites (with the exclusion of newly discovered materials at a higher elevation) are rusted and show signs of corrosion from exposure to terrestrial chemicals, however some still display areas of fusion crust. The structure of a Campo del Cielo meteorite is known as a polycrystalline coarse octahedrite, and it carries a Widmanstatten pattern just thin enough to keep the coarse octahedrite classification. Campo del Cielo meteorites available for collection are classified in Group I - they a iron nickel alloy which accounts for approximately 90% of the recovered material available for specimen sales. They originate from Chaco, Argentina and may be Coarse IAB, Octahedrite with possible silicate inclusions and may contain varying levels of iron and graphite. Because not all of the material belonging to the Campo del Cielo Meteorite has fully recovered, no estimation is given to the amount that's available  Sikhote-Alin Meteorites: On February 12, 1947 all was quiet in the Sikhote-Alin mountains just north of Vladivostok and east of the China border. The Sun had just risen and the skies were clear and cold. Then it happened... At 10:38 a.m. local time a huge fireball appeared from 15 degrees east of north at a 41 degree angle, slashing through the skies at an estimated 31,000 miles per hour. For a few brief moments, it outshone the Sun... then about 3.5 miles above the Earth's surface, it exploded violently. What could have left a trail of smoke and dust 20 miles long? Evidence of its entry lingered in the air for hours afterwards and the light and sound of the impact were recorded from 200 miles away from the point of impact. The Sikhote-Alin meteorite fall is one of the most spectacular in recorded history. When it fragmented, the group fell to Earth together to cover an oval area that measured roughly half a square mile in size. One of the largest of the pieces formed a crater 85 feet in diameter and 20 feet deep! The explosion was so incredible that fragments were even lodged in trees... Just how big was this intruder from space? Experts judge the total mass of the Sikhote-Alin meteorite may have been near 1000 tons. The largest fragment of the Sikhote-Alin meteorite is a 1,745 kilogram specimen retained by the Russian government and now on display in Moscow. There are many specimens around that weigh as much as 1000 kg (displayed at the Russian Academy of Sciences), but most are smaller fragments. The Sikhote-Alin meteorite is one of the coarsest octahedrite known, with its Widmanstatten pattern nearly a centimeter wide. In smaller sliced specimens, this means you may not even be able to see crystal structure at the edges at all. While Sikhote-Alin meteorites are all iron nickel alloy classified in Group IIB, they display two very distinct types. The first is known as a "Complete Individual". This group of Sikhote-Alin meteorites will display ablation and fusion crust. Many or most of these whole specimens will also contain regmaglypts, ablation cavities which look like small thumb prints in the surface of the meteorite. The second type of Sikhote-Alin meteorite fall specimen is called a fragment. These irregurlarly shaped chunks can only be likened to shrapnel - because this is what they are - the remnants of where the meteorite exploded above the Earth's surface. Some fragments may display shield shapes, show fine lines known as striations, or even give signs of their direction (orientation) from where they fell. Sikhote-Alin meteorites only became available on the legitimate international meteorite collector's market after Russia changed its politics. Out of the total known weight of 28 tons of collected material, no estimate has been given about how much will be allowed to be purchased by private collectors and Sikhote-Alin meteorites may only be available for a limited time.  Canyon Diablo: Located in the heart of Arizona, Canyon Diablo Meteor Crater (the "Devil's Hole") was known to the Indians as a cursed place long before science began exploring its extra-terrestrial nature. The fall which caused what is now known as Barringer Crater occurred between 20,000 and 40,000 years ago and its mass may have been as much as 63,000 tons. When this 80 foot in diameter metal rock came flying down from the sky at 9 miles per second, it smashed into the desert floor unleashing 1.7 megatons of energy - the equivalent of 1.7 million tons of TNT. The result was a massive crater that spans 3400 feet across, runs 600 feet from rim to floor, and with a rim that raises above the desert surface an additional 200 feet. The first meteorites recovered and recorded from the Canyon Diablo fall gained research attention in the mid nineteenth century, but it was nearly the twentieth century before dealers began to make them available for collector trade. Because of their iron nickel content, geologist Daniel Barringer recognized the crater as a potential site for mining, staked a claim on the site and began searching for a huge mass - one which was never found. So what happened to the smoking gun? It vaporized on impact...  Thanks to the work of Harvey Nininger, we learned that some of the iron condensed after it was vaporized and just where those tiny droplets might be found. The largest Canyon Diablo meteorite ever recovered weighed a modest 639 kilograms and it is currently on display in the Meteor Crater Museum. Very rare are any pieces which weigh 100 kg and only a very, very few have been recovered that tip the scales at 10 kg. Out of all of this huge amount of material, Nininger estimates that only 30 tons of documented Canyon Diablo meteorites have been recovered - and as much as 8,000 tons may yet exist as material as finely grained as sand. Much of it may still remain around the Barringer Crater, but it is now closed to meteorite hunting and only previously collected samples are available on the legitimate market. Canyon Diablo meteorites are Group I, coarse octahedrites, iron nickel with varying mineralogy depending on whether or not the sample was shocked at impact. About 90% are typical iron nickel alloy. Some specimens show may show evidence of partial melting, recrystallization, and deformations.  Northwest Africa (NWA) Meteorites: Northwest Africa (NWA) Meteorites began to appear strongly on the meteorite collector's market just before the dawn of the new century. For many years prior, collectors had been treated to rare samples from the Morocco and Western Sahara area, but the value quickly dropped when the mass influx of material began. Why? There really isn't a simple answer, but let's try to shed some light on some common misconceptions about Northwest Africa (NWA) Meteorites. Part of what makes any particular meteorite valuable is its documentation. Where exactly was it recovered? Was it observed? When was the piece recovered? How much was recovered? Was the site documented? And so much more... When archaeologists trained native residents to look for fossils, they also trained them to look for meteorites as well - and they were very successful. However, in their haste to make money and to guard their resources, these guidelines were often overlooked. And who could blame them? As a result, the huge influx Northwest Africa (NWA) Meteorites caused their value to drop sharply because they can't always be classified, nor documented... But that doesn't mean they are any less genuine. Most NWA meteorites are carbonaceous chondrites, and some are ordinary chondrites. Still other Northwest Africa meteorite fall specimens are in the howardites, eucrites, ureilites, and rare achondrites categories as well. When these types of classified specimens are for sale to collectors, they will be listed by gram weight and given numbers such as NWA 098 - which is an official Northwest Africa meteorite, an ordinary chondrite with 7.14 kg of material recovered in the year 2000. Classified specimens will be specifically stated as classified and registered with the Meteoritical Society. Northwest Africa meteorite fall specimens listed as "unclassified" are just as genuine, put in the proper category as far as meteor type, but simply lack full documentation. Never underestimate the value of a Northwest Africa meteorite! Some of the most important meteoritical finds have been from this area - including lunar basalts (NWA 032 and 479) and Martian meteorites (NWA 998 and 1195). You just might get a diamond in the rough! Join David Holden at his talk about Sky Stones, enjoy his wonderful display and be sure to purchase your own meteorites while you're here at Hidden Hollow! |
