Meteorite Times Magazine Contents by Editor
Featured Monthly Articles Accretion Desk by Martin Horejsi Jim’s Fragments by Jim Tobin Meteorite Market Trends by Michael Blood Bob’s Findings by Robert Verish IMCA Insights by The IMCA Team Micro Visions by John Kashuba Norm’s Tektite Teasers by Norm Lehrman Meteorite Calendar by Anne Black Meteorite of the Month by Editor Tektite of the Month by Editor
Meteorite Times Magazine Linum, Germany: It’s What’s For Breakfast! by Martin Horejsi
Linum, Germany: It’s What’s For Breakfast!
Linum is one of those rare meteorites whose date of fall is within a few years of its TKW in grams. In this case, the Linum fell in 1854 with a total known weight of 1862 grams. Mike Bandli has an excellent description of the fall of Linum, translated by Werner Schroer on his website. Here’s a taste from the story: Shortly before 8 o’clock, around the time of breakfast, on the 5th of September of the year, I was standing on the digging fields that are located near the meadows of the Wustrau farm. There were no clouds in the sky, the air was clear, the water was still. I was intrigued by a strange noise; it was as if the windmills of the adjacent digging plant were spinning and I wondered why this could be happening when no wind was around.
The amazing crust is so evenly distributed along the edge of my slice that itâ€™s as if the layer of crust was manufactured separately from the stone, then installed after landing.
The Linum chondrite fell a full century before the historic-feeling Sylacauga, Alabama meteorite.Well, perhaps Ann Elizabeth Hodges who was on the receiving end of the Sylacauga stone didnâ€™t think it felt quite so historic.
For an L6, Linum does have some very nice chondrules including the large, almost perfectly circular spherical cross-section in the upper left of this slice.
Even before the summer solstice, this year has proven itself an exciting one for meteorite aficionados. But that is not reason enough to stop looking backwards for exciting meteorite falls. And there is still a wealth of great stories from the 1800s including that of Linum, Germany. Until next timeâ€Ś. The Accretion Desk welcomes all comments and feedback. firstname.lastname@example.org
Meteorite Times Magazine Californiaâ€™s Recent Meteorite Fall by Jim Tobin I named this article as I did to avoid the problem of picking a name myself when it has not been officially named as of the time of this writing. My story of the meteorite fall near Coloma, California began with my wife asking if I had seen the video of the beautiful fireball that came over Nevada and California. I had not seen it, so the Internet search for information began. The size and explosion strength were soon to be estimated. NASA said quickly that it had been the size of a mini van and had exploded with 3-4 kilotons of force. There was still discussion about where any pieces might have landed. Well, this was my chance to go hunt a fall right away. I had no commitments for a while and the free time to go. But, I wanted to wait until the location was determined and whether there were even pieces on the ground to find. I did not have to wait long after a couple days the first several pieces had been found and I got on the computer to determine just exactly where Coloma was. That is when the first big decision was forced upon me. Coloma was just a short loop up and over Folsom Lake from Rocklin. What does Rocklin 30 miles away have to do with the meteorite fall? My middle daughter was to graduate from William Jessup University in Rocklin on May 12. Three months before the meteorite fell we made hotel reservations and plans to go up there. Now my decision is do I go up early for a few days and find a place near Coloma to stay. Return home, then turn around and go up again with my wife. When the pieces began being found and they were all small and they were being found very slowly it made more sense to wait just a few days and go up as we had planned. We had two free days built into the trip with no activities planned. So meteorite hunting and a nice visit to gold country was going to be great. We drove straight to Coloma from LA and got there around noon. You have to start out early or you get caught in morning traffic. I had picked a road west of Coloma; but not too far to try my luck at hunting for pieces that may have flown farther. As it turned out there was not a lot of room next to the sides of the road. But, we found some spots and turnouts and hunted there for a couple hours diligently.
Then we drove toward Coloma and pulled into Henningsen Lotus Park and hunted there for a couple more hours. No meteorites, but as a long time hunter it is part of the process to put in the time without success so you can scream and howl for a few minutes when you do find one. I did find a couple nice pieces of colored native rock that were beautiful. May do something with them someday. In the late afternoon we
headed to Rocklin to check in to the hotel. But, we would be back in the morning for some gold panning first while it was cooler and meteorite hunting the rest of the day.
This shot is of the large grassy area at Henningsen Lotus Park. There were several others hunting there while I was there. Four men with magnet sticks passed me discussing what the meteorites should look like. I sort of smiled inside myself. The refrigerator in our hotel room was so noisy I did not sleep very well. But, by the time we got to Coloma I was ready to find gold and meteorites. I found a promising area to pan on the edge of the public recreational panning area. I had my concentrator screen and pans for myself and my wife. Slurpper bottles, gold tweezers, storage bottles and a magnet were all packed in a small shoulder bag in addition to my normal meteorite hunting stuff. My wife did not want to hike down the steep embankment and risk a fall so I would spend a couple hours panning by myself I thought. Well, there were about 20 kids and some adults along with a tour guide at the river when I got down there. They were working in a shallow of the river almost a beach you could call it. I went upstream a little ways and found some rocks half in the water and half out. I crevice scoured around and under the small boulders and put it all though the concentrator screen. Threw away all the larger rocks which I normally would not do without metal detecting them. Then panned it out over where the kids were. I could sit down to pick out the gold if there was any and I could stand in the water up to my knees to pan. After a minute or so of panning I had washed off enough of the sand and small gravel to take a look if there was any gold. I agitated the material to one side and rolled the sand and gravel off with a wave or two of water. There in the bottom in a lot of black sand I could see some flakes. So I finished off the panning down to just a little sand and no gravel and found a nice little line of color in the pan. The kids were all standing around and I showed them what the gold looked like so they could tell it from mica or something else shiny. I showed the parents how to pan a little and told them to go slower and hold the pan flatter. They were letting most of the sand and gravel out too fast without moving the pan much. Unfortunately, they were on a schedule and it was about time for them to leave. One man I had helped came over and requested I give him a single piece of gold so he could take it home to show his brother. I slurped up a piece and put it in his waiting bottle. He thanked me and I said good bye to them. I was alone now. I got back to work and panned a few pans and slurped up the gold. There always were a few flakes in each batch of concentrate. You are suppose to just use hands and pans so with just the help of a stick I continued to work out the contents of the crevices as far down as I could get. After a couple hours I knew I could not leave my wife up there hunting meteorites by herself much longer so I made up an empty water bottle of concentrate to take back to the truck and pan out there. She had never really panned for gold. I hiked back up to the truck and got her set up on a rock where she could sit. I dumped the sandy glop into her pan. We worked over another pan just in case she spilled accidental.
But, she got the knack fast and was washing off the sand and gravel while moving the pan. Both the pans I brought were old plastic types with riffles on one side. Good pans though. When she got down to very little sand left I helped her just to wash the contents back so we could see if there was gold. She had some in her pan and I was pretty happy about that. We saved her concentrate since I think there may be a little more that I can get since she was just learning how much to tilt the pan.
Guess I was a little excited because I forgot to take a picture of the first pan. This is the second pan with black sand and some regular sand still in it.
This is my gold after a long cleaning process to remove with a tiny magnet the remaining black sand. My total finds were 1.569 grams. My wife's finds were .1665
grams from her single pan of concentrate. It was great fun but we did not even find enough to pay for the gas one way of the trip up there. Imagine how much had to be found in 1849 at the low price gold was then. As they always say it is better to sell the miners the tools and supplies then to do the mining. Now it was meteorite hunting time. We drove back across the single lane bridge and into the Marshall Discovery Park parking lot. In the next five hours I covered as much of the area there as I could. I knew it had been hunted by others. Yet this is a fall where not just diligence is required but a lot of luck. So I hunted the corners, the edges, under the trees and along the bushes. All places I know others had probably been too. But, with limited time I had to do the best I could. I did not find any of the meteorite. A lot of interesting other rocks, some charcoal that was pretty close in appearance and hardness. But, close inspection showed the faint remains of the hardwood grain. My heart did sink on the first piece of that charcoal I found. I had a moment when I thought it might be a piece of meteorite. There were no fire pits or BBQs nearby. After a real close look though I ruled it out with some sadness.
This is one of the large grassy fields at Marshall Gold Discovery Park. It was mowed and easy to hunt but I knew it had been well searched already. So I worked all the edges too and around as far as I could walk into the off areas. Everywhere as I walked in the area of the Marshall Gold Discovery Park I could see the grass was either trampled down or had paths winding through it. I wondered sometimes if all these hunters were actually hunting meteorites or trying to make crop circles. Some areas off the path by trees were totally trampled down. I hunted as hard as I could but did not have the time to do that kind of exploration through the grass, wish that I had been able to stay long enough for that. Clearly that is now where the pieces mostly are. It is just really hard to see through all the grass to the ground. With late afternoon approaching and we had not been to the visitor center/museum we headed that way to see it and get some souvenirs at the gift shop.
Just one spot where the grass was trampled down from hunters walking on and through it. We entered the museum and soon found ourselves in a great conversation about meteorites and the hunting of them. There was a picture of some pieces that had been found taped to the counter. As I was talking with the two ladies behind the counter a gentleman asked if I could identify a real piece if I saw one. I said yes and we went out to his car. He had a piece of black rock. It was not the dark grey slate that is everywhere but a true black rock. It was not magnetically attractive. Too bad it was crystalline and had some quartz inclusions in it. So I told him it was not a piece of the meteorite. He said he did not really think so either. His dad had been an oil exploration geologist, so he had learned a lot about rocks himself. We chatted a while then went back in the museum and actually got through it this time. I found a couple souvenirs and made three smashed pennies. While outside the gift shop my wife walked near another woman sitting on a bench who said to my wife, “I know you.” My wife looked at her and said her name. As it turned out she was a teacher at the same school as my wife’s sister-in-law. The school is at the church my wife grew up in and attended until we married and she moved. While they are chatting the wife of the man I had given the gold flake came and sat down with them. The kids and parents down at the river panning were all from the school that my brother-in-law’s wife teaches at. If I had known that I would have given him a bigger flake of gold. We had not had lunch so we made up a little snack from the cooler. I had seen a person with a slushee type drink and asked where she had gotten it. So I was off to the Coloma Grange across the street for a couple large cool ones. Two coke slushees in hand we got ready to drive back to Rocklin. We found no meteorites, but had a great time and some luck panning gold. More great meteorite memories and I can always say I was there and tried. Can not find meteorites sitting on the couch at my home I know that. Daughter Laurie graduated on Saturday and we had a nice but long drive home. Will I return in the fall to look when the grass is dead? I don’t know I guess that will depend on how finds continue to be made. If much more is found and some large pieces are recovered maybe I will. If little more is found and nothing large, maybe not. The meteorite is friable and will not last long. It is a shame if not much is found. But, I think it possible that most turned to dust in the explosion and unless big size finds are made it may be that there are not big pieces to find. I hope that is not the case, time will tell. I am writing this while it is still pretty early in the story of the Coloma area meteorite. Hope it gets an official name soon. Right before we left we took a little drive around the area of Coloma and we drove the full length of California’s shortest state highway. It is only about a half a mile long I guess and ends at the James
Marshall Memorial. But what a great sign I had to share it.
Until next month, Jim
Meteorite-Times Magazine Meteorite Market Trends by Michael Blood Like
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Meteorite Times Magazine IMCA Insights â€“ May 2012 by IMCA TEAM
IMCA Insights â€“ May 2012 Introduction to Meteorites by Dolores H. Hill Meteorites are tangible samples of the Solar System objects traditionally studied by ALPO members and many other astronomy associations. They provide a connection to such things as the meteors, minor planets, comets, lunar, Mars, and even the Sun (as implanted solar gases). Naming of Meteorites... Unlike astronomical bodies, meteorites are not named after their discoverers or even famous scientists. They are named after geographical features, towns, or regions. Attempts are made to use names that are not likely to change and are easily identifiable. It is only recently that some standardization has been applied to the naming and official recognition of meteorites. The Nomenclature Committee of the Meteoritical Society is the official body for approval of names and classifications of meteorites. Where are Meteorites Found?
Gold Basin meteorite, as found (Photo courtesy of A erolite.org)
Meteorites generally fall at the same rate over the entire Earth. Because the Earthâ€™s surface is mostly water, most of them are lost. They are recovered wherever people live and travel. This is evident on maps of meteorite recoveries as "paths" during the building of large railroad and road building projects. Meteorites are best preserved in dry environments where weathering and rusting is relatively slow. They are also more easily seen against light-colored soils and sparse vegetation. In more temperate climates, meteorites begin to rust immediately after falling and are subject to destruction from plant roots as well. Thousands of meteorites have been found in Antarctica and the Sahara Desert in the last 20 years. This is more than was known previously from the entire world. Not only have these meteorites
expanded the known types but, they have increased our knowledge of ancient meteorite falls. They have provided evidence of the timing of breakup and types of asteroid parent bodies that produced the specimens in our laboratories. Meteorite Types & Classification
Begaa: stony meteorite, chondrite LL3 with numerous clear chondrules (Photo courtesy of A nne Black)
Contrary to popular misconception, not all meteoroids or asteroids are metallic. In fact, most of the meteorites that fall on the earth are stony meteorites called chondrites. They are named after tiny objects or inclusions in them called chondrules. These are spherical, ~1 millimeter diameter, silicate inclusions formed early in the formation of the Solar System as the Solar Nebula coalesced; before any of the planets or asteroids formed. Indeed, chondrites are the oldest rocks you can hold! Other meteorite types represent a wide variety of conditions and processes on various parent bodies. They provide valuable insight into the Solar System's past throughout space and time. Iron-nickel and stony-iron meteorites sample deep interiors of once large asteroids. They are used as analogs for our own Earthâ€™s core and mantle. Other meteorites are brecciated; composed of broken fragments of asteroid collisions whose record has been frozen in place. The details of the meteorite classification scheme will not be discussed here. As alluded to above, there are three main types: stony, stony-iron, and iron-nickel. Each of these broad categories is broken down into many types based on their mineral and chemical compositions. The age-old battle between classifying "lumpers" and the "splitters" is carried out as similarities and differences between individual meteorites are learned. Scientific lumpers look for similarities between samples and put them together in a category; splitters look for differences between samples and create separate classifications or categories. As more meteorites are recovered and we sample more Solar System parent bodies, more sub-types seem to be required until a unifying explanation can be found to link them to a common parent asteroid. The three main types of meteorites are readily discernible by eye but, sophisticated instruments are required to determine an exact chemical classification. Sometimes, lengthy trace element analyses are required to distinguish between some meteorite classes. Where do Meteorites Come From? We know that the meteorites in our scientific collections primarily sample the asteroid belt between Mars and Jupiter. This is known from orbits calculated of fireballs that were photographed and later recovered. There is evidence that some meteorites were formed at different distances from the sun. It is possible that some carbonaceous chondrites are related to comets that sweep into the inner Solar System. They are "primitive" chemically (unchanged since their formation early in Solar System history) and some contain minerals that have been exposed to water. We have been able to conclusively identify "lunar meteorites" from their unique chemical signatures because we have real samples of moon rocks from the U.S. Apollo and Soviet Luna missions. Martian meteorites or "SNCs",
named after the three type meteorites, Shergotty, Nakhla, and Chassigny, were first known from compelling circumstantial evidence. As more compositional data from the surface of Mars becomes available, the connection is even stronger. We do not think we have samples of Mercury or Venus but, meteoriticists have thought about what kinds of compositions would be expected. There are a few pre-solar grains trapped in carbonaceous chondrites that sample material from a different solar system! How is a Meteorite Identified? The most important comment to be made about meteorite identification is that it ranges from very easy for those with "classic" fusion crust to very difficult for older finds and/or unusual types. The specific classification of a particular type of meteorite requires chemical analyses by an institution with access to an electron microprobe and/or a trace element laboratory. It is interesting to note that meteorites contain the same elements and, with some important exceptions, similar minerals as are found on the Earth. Physical Appearance: Fresh Falls vs. Old Finds
New Concord, with fresh black fusion crust, fell on May 1, 1860, and recovered immediately (Photo courtesy of A nne Black)
The first indication that a rock may be a meteorite is its outer surface. A fresh fall, i.e. a meteorite that is seen to fall and soon recovered, will exhibit a black surface. This outer coating or "fusion crust" is less than 1 mm thick. It ranges from a matte black luster to a glassy black depending on the stone's composition. The fusion crust is the last, quenched, outer layer of the meteorite as it passes through the atmosphere. It is an often misunderstood feature. Real fusion crust usually doesn't look particularly melted or vesicular. Fortunately for scientists, most of the interior is well preserved and not harmed by the heat of atmospheric passage. Would-be meteorite finders bring scientists many lumps of magnetite, volcanic rocks, slag, and even rocks containing calcite that are brought in because they "look melted".
Bendego: old, highly weathered meteorite found in 1784 in Brazil (Photo courtesy of A nne Black)
Meteorites that are old "finds" will have lost the beautiful black color to the fusion crust. Because meteorites are immediately attacked by Earthâ€™s atmosphere and moisture, they oxidize (rust), weather, and erode. They often have an ugly, rusty, brown exterior that may be broken and severely cracked. Some, although rusted, may retain traces of the original fusion crust. Density While it is true that meteorites are denser than terrestrial rocks, it is a poor criterion. Earth rocks containing mixtures of minerals, ores, and basalts may, by chance, have a similar measured density. Iron meteorites will be very heavy for their size, but iron-rich slag and magnetite will be heavy also. Some stony meteorites may be indistinguishable in the field from other rocks if density alone is considered. Magnetic Properties Iron-nickel meteorites are strongly magnetic but stony meteorites will be much less attracted to a magnet. Most stony meteorites contain small grains of iron-nickel metal. They will be detected by a well tuned metal detector even several inches below the surface. Unfortunately, many ordinary rocks also exhibit magnetic properties. Rocks which are strongly magnetic on one part but, not on another, are terrestrial volcanic rocks, basalts, or other iron-rich rocks and industrial slag. So, magnetism alone is not a very useful discriminator. In summary, exterior appearance, density, and magnetism are useful aids, but do not provide definitive tests by themselves. Unless a specimen is obviously terrestrial or obviously a meteorite, a cut is required to reveal the interior secrets. The first indication of a stony (chondrite) meteorite is the presence of small, reflective metal grains or flecks in a silicate groundmass. This groundmass can range from a light gray color to dark black. Some but, not all, chondrites will exhibit ~1mm diameter, circular, chondrules. Most people greatly overestimate how large these are and often mistake sand grains in Earth rocks for chondrules. Other, rarer, stony meteorites require careful microscopic or chemical analysis by a meteorite laboratory.
Saint A ugustine: Iron meteorite found in 1974 in Illinois (Photo courtesy of A nne Black)
Iron-nickel meteorites when cut will have a "nickel color". This can be difficult to assess. A bluish hue to the metal or glassy, melted-looking inclusions with vesicles indicate a manmade metal or slag. The
famous Nital etch can reveal the WidmanstĂ¤tten pattern in a metal meteorite as it preferentially etches the minerals at different rates. (Donâ€™t try this at home! It is a dangerous mixture). This crisscross pattern is diagnostic of a meteorite because it is formed only by very slow cooling in the interior of an asteroid. Often metal meteorites are positively identified by analysis of their iron and nickel content with an electron microprobe. A large amount of calcium, manganese, copper, zinc, silicon, indicates a manmade origin. Common Meteorwrongs
Hematite, a common meteorwrong (Photo courtesy of A erolite.org)
The most common meteorwrongs include magnetite, a black, heavy, magnetic rock, industrial slags of all descriptions, old iron farm implements, iron rich rocks, and volcanic rocks. Many brown or black rocks are sent to labs in hopes that they are meteorites. Knowledge of the geologic or geographic setting can be important in any explanation of the true nature of a meteorwrong. For example, many rocks from deserts display a thin, black coating called desert varnish that can look very much like fusion crust but, is actually a terrestrial manganese oxide. Testing Laboratories
Dr. K. Domanik studying a sample of A lmahata Sitta with the electron microprobe, in the lab of the University of A rizona, Tucson, A rizona (Photo courtesy of Full Moon Photography)
Meteorite laboratories are usually associated with universities. They routinely examine possible meteorites. Not all geology departments and not all geologists have experience with meteorites. Reputable meteorite dealers are also qualified to identify common meteorites. They, too, will seek out scientific contacts for unusual rocks or meteorites. I have never known of a dealer to be dishonest,
that is, to tell a person that they do not have a meteorite if they know it to be one. It may be disappointing to be told that your find is an ordinary rock but, be assured that there are plenty of real meteorites waiting to be found, and more falling every day. Because meteorite laboratories must examine possible meteorites in between their regular work, there is no set time frame for completion. An instant answer is usually a "no". Longer delays indicate that the sample is "in the queue" and may not have been examined right away. Or it may mean that it is a difficult to identify specimen that may or may not be a meteorite after lengthy analyses. Certainly, any unusual or rare meteorites are given highest priority. The Scientific Record The official recognition and naming of meteorites is carried out by the Nomenclature Committee of the Meteoritical Society. It has set forth rules that must be followed by institutions submitting information for new meteorites. (See below). New meteorites are announced in the Meteoritical Bulletin several times per year. A preliminary version is posted on a website and the final, official version is published in the journal, Meteorites and Planetary Science (MAPS). The Catalog of Meteorites is a compilation of the Bulletins that has been published in book form approximately every 10-20 years. Not only does it give one great satisfaction to contribute to the scientific record but, there is added satisfaction in seeing your name as the finder and/or owner of the main mass of a newly discovered meteorite. Other than for the sake of the scientific record for future generations, why go through the trouble to have a meteorite properly classified and recognized? One reason is that if you ever wish to sell it, you will obtain a higher price for an officially recognized specimen with a real, scientific classification. Without one, dealers understandably will pay the "market price" for the least valuable type. If it turns out to be one of the rare types of meteorites, they will be elated and you will have missed an opportunity. Be forewarned, though, that while most meteorites are ordinary chondrites, they also are not extremely valuable either. Too often meteorite owners hope that theirs will allow them to retire or buy a vacation home, etc. because of sensational T.V. programs that emphasize the rarest types. The best way to enjoy a found meteorite is to appreciate its scientific significance and proudly display the specimen for all to see. Collections
Display of meteorite specimens, during the Tucson Show (Photo courtesy of A nne Black)
Meteorite collections are found all over the world. They are housed in large and small museums, planetariums, universities, and private collections. Museum collections are primarily for display and educational purposes. They do occasionally provide specimens to researchers. Universities and other institutions such as NASA-Johnson Space Center, maintain collections for the purpose of scientific research. Individual laboratory collections may be more specialized and, therefore, often contain smaller or fewer samples than most collections. The Smithsonian Institution is an example of an institution that serves a role as both museum and research facility. The most important part of any collection is to preserve the meteorites, keep the original identifying labels with the specimen and to keep an inventory list. Private collectors include amateur astronomers
and mineral collectors who just enjoy the idea of holding and preserving a piece of an asteroid. Some attempt to collect an example of every "type" of meteorite; some concentrate on falls; some collect them by alphabet A to Z; some collect all meteorites found in one particular state or country; some desire only the rarest samples to fill out their collections. Many collectors are discovering the joys of thin sections; 30 micron thick, polished slices that reveal a new world under the microscope. Collectors include commercial meteorite dealers who have built beautiful collections of both museum quality specimens and smaller pieces suitable for the amateur and scientist. They, too have their favorites that are considered part of their "private collection". Dealers often cultivate a symbiotic relationship with scientific institutions and are, thankfully, very generous to them. They provide an educational role to the public as well. What to Do if You Think You Have Found a Meteorite? 1. Send the entire rock to a meteorite laboratory associated with an educational institution for documentation of its original appearance, weight, interior structure, etc. It is wise to contact the institution ahead of time so the sample is expected and directed to the appropriate person. 2. Provide a complete description of the "find" location and circumstances. This information is needed to assign a permanent, official name to the meteorite, check for possible pairings of meteorites found in the same region, and allow for future recovery of more specimens. It is also important for proper recognition of the discoverer(s) and current owner(s) in the scientific record. 3. In accordance with the requirements of the Nomenclature Committee of the Meteoritical Society, 20% or 20 grams (whichever is smaller) of the specimen must be donated for curation for future research. The material needed for initial analyses by most laboratories would be taken from this 20% unless permission is obtained otherwise. Contrary to popular belief, laboratories never require donation of an entire specimen. 4. Most (all?) laboratories do not charge for their services. This is latter is fortunate for meteorite owners because the cost of materials, personnel, and instrumentation usually far exceeds the actual commercial value of the entire rock. It is in the interest of scientific research and public service that labs conduct such work. Most labs request the ability to conduct exclusive analyses on a particular meteorite until it has been classified. This is because, although there are several laboratories capable of conducting meteorite authentication and analyses, it is unproductive and, indeed wasteful, of time and resources for several labs to duplicate initial classification. They are contracted to carry out research as stated in funding proposals over a year in advance, so unfortunately that work takes priority over newly found meteorites. It may take a long time before classification is complete. Why wait? In addition to providing scientifically invaluable specimen for future curation, classification and official recognition is essential to collectors and dealers. Do's and Don'ts of Meteorite Preservation The most important advice one can give about meteorite preservation is that least is best! Never (!) attempt to remove fusion crust or soil unless the latter rubs off very easily by hand. Fusion crust protects the sample and its presence is highly prized by other collectors. It is best to leave any cutting to professionals who have special saws, thin diamond saw blades, inert diamond polishing compounds, and access to high purity chemicals. It is difficult for the average well-meaning person to know how a sample may become contaminated for scientific studies or preservation. In dry climates, only polyethylene bags or plastic boxes and desiccant stored with the specimens may be needed. However, in moist climates, sealed containers and cabinets with desiccant may be required to prevent atmospheric attack of a collection. Certainly, moisture and oxygen present the most serious threats to any meteorite. One must be careful not to seal in moisture during storage. High temperatures to drive off moisture should be avoided as they may also alter the chemical properties of a meteorite for age dating. Several iron-nickel meteorites display altered or lost Widmanst채tten patterns due to reheating by their finders. Some collectors resort to coating their iron-nickel specimens with special varnishes and lacquers, and even soaking in penetrating oils. Oils may ooze out as time passes - or if placed into any analysis instrument that uses a vacuum. (Dealers will sometimes use varnishes to protect a specimen that will be on display in a humid climate. They will always inform you). As a scientist with an eye to future studies and techniques, these are met with mixed enthusiasm. Some may preserve a specimen but, render it useless for any scientific studies. The alternative is a rusty pile of debris. A person may not intend for a specimen to be studied but, 20 or 50 years from now it may be the only known piece of
an important sample. For instance, for the ALH 84001 Martian meteorite and its claimed nanofossils; much of the scrutiny depended on how it was collected, stored, and subsequently handled. It was one of the "difficult" meteorites to classify and was later discovered to be Martian because it was included in a study of other rare meteorites.
Dolores Hill in the Lab in the University of A rizona, Tucson A rizona (Photo courtesy of Full Moon Photography)
Dolores Hill, Senior Research Specialist, Lunar and Planetary Sciences, University of Arizona, Tucson, Arizona, wrote this Introduction to Meteorites for the website of the Association of Lunar and Planetary Observers (ALPO) a few years ago. The latest meteorite falls and media interest on the subject has attracted a lot of new comers to the field of meteoritics and I believe it is important every now and then to review the basics, so she has allowed the IMCA to reprint it here. Thank you, Dolores. Anne Black, Editor This article has been edited by Anne Black and Norbert Classen. • IMCA Home Page • IMCA Code of Ethics • IMCA Member List • Join IMCA • IMCA Meteorite Info
Meteorite Times Magazine Almahata Sitta by John Kashuba It seems understatement to say that Almahata Sitta is polymict given that it contains at least twelve lithologies. Since the lithologic types are dominated by ureilites, though, it is classified as a polymict ureilite. Much of the remainder is EL and EH chondrites of various petrographic grades, melts and breccias. Also found are H and L ordinary chondrites and a unique chondrite. Roger Warin and I wrote about Almahata Sitta for Meteorite magazineâ€™s February 2012 issue. Our Centerpiece article used some of the following pictures.
Almahata Sitta Coarse Grained Ureilite
Almahata Sitta Coarse Grained Ureilite
Almahata Sitta Coarse Grained Ureilite
Almahata Sitta Coarse Grained Ureilite
Almahata Sitta Fine Grained Ureilite
Almahata Sitta Fine Grained Ureilite
Almahata Sitta Fine Grained Ureilite
Almahata Sitta EL6
Almahata Sitta EL6
Almahata Sitta EL6
Almahata Sitta EL6
Almahata Sitta H5/6
Almahata Sitta H5/6
Almahata Sitta H5/6
Almahata Sitta fragment MS-CH unique chondrite
Almahata Sitta fragment MS-CH unique chondrite
Meteorite Times Magazine TEKTITE THESES, THEMES, TROPHIES, & TRIVIA: Dragon Tracks! by Norm Lehrman
This spectacular Thailandite from the Khorat Plateau region of northeastern Thailand, exhibits exceptionally well-developed skin splits. These formed after the skin had cooled sufficiently to react in a brittle manner while the interior remained soft and gooey. When this water balloon-like blob splatted, the skin split open revealing the viscous interior. Note the contrast in skin ornamentation between the two regions. I am often asked if I consider these to be “stretch” tektites. I don’t, but in principal they are exact equivalents. The classic Nininger stretch tektites involve a bending angulation, where the degree of angulation is matched by a similarly angled split along the opposite edge. The difference is academic, but good stretch tektites following this definition are quite rare and expensive, while skin splits or starburst rays are quite common. The starbursts typically radiate from an indentation along the rim , possibly reflecting an impact point. The pattern is often termed a “dragon track” in China.
Meteorite Times Magazine Meteorite Calendar â€“ May 2012 by Anne Black Please click on the meteorite calendar to view a larger image.
Meteorite Times Magazine Lâ€™Aigle by Editor Our Meteorite of the Month is kindly provided by Tucson Meteorites who hosts The Meteorite Picture of the Day.
Contributed by Mexico Doug, L'Aigle 31 gram. Chondrite L6 Submit Pictures to Meteorite Pictures of the Day
Meteorite Times Magazine Darwin Glass by Editor Darwin glass is an impactite caused by a meteorite impact. This natural glass is found south of Queenstown in West Coast, Tasmania.
Five Darwin glass specimens.
Translucent green specimen very reminiscent of moldavites.
Has little beads of glass attached similar to Irghizites.
36 gram specimen that shows flowing glass.
Backside of 36 gram specimen.
Notice there are roots in one of the bubble cavities from when it was in the ground.
Side view: 36 gram specimen.
Opposite side view: 36 gram specimen.
All Photos ÂŠ Copyright by Daniel Sutherland
Meteorite Times Magazine Meteorite-Times Sponsors by Editor Please support Meteorite-Times by visiting our sponsors websites. Click the bottom of the banners to open their website in a new tab / window.
Once a few decades ago this opening was a framed window in the wall of H. H. Nininger's Home and Museum building. From this window he must have many times pondered the mysteries of Meteor Crater seen in the distance. Photo by ÂŠ 2010 James Tobin