Re: [meteorite-list] Pallasite Info/Pictures
Here is the data for the Quijingue pallasite found in Brazil. The data is from the Catalogue of Meteorites, by Monica Grady. Met. Bull. No. 83, MAPS_ 34*, A169-A186 (1999) M.E. Zucolotto, Mus. Nac., Brazil; J.T. Wasson, UCLA, USA A 59kg meteorite was found ~1m underground by a farmer digging holes to plant trees. It was given by the farmer's son to a miner, Aparecido Crespi, who had the object identified. Classification and analysis (M.E. Zucolotto, Rio; J.T. Wasson, UCLA): olivine, ~70 vol%; Ni content of metal, 7.5 wt%. - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Sent: Wednesday, December 11, 2002 10:50 PM Subject: [meteorite-list] Pallasite Info/Pictures Hi list, I am currently trying to get some information and pictures on all the known pallasites, but I'm having some trouble with certain ones. I currently have pictures and information on: Admire, Ahumada, Albin, Brahin, Brenham, Dora, Eagle station, Esquel, Giroux, Glorieta Mountain, Hukitta, Imilac, Krasnojarsk, Marjalahati, Molong, Mount Vernon, Palvodar, Quijingue, Somervell County, Springwater, and Thiels Mountain. I have information on most of the following but can't find any pictures of: Acomita, Argonia, Barcis, Bendock, Cold Bay, El Rancho Grande, Finmarken, Itzawisis, Lipovsky, Marburg, Mineo, Mount Dyrring, Newport, Omolon, Otinapa, Phillips County, Rawlinna, Santa Rosalia, Singhur, South Bend, Sterling, Vermillion, and Zaisho. So if anybody on the list has pictures, information, or can name any pallasites that I didn't list, your help would be greatly appreciated. Sincerely, Chris Brooks P.S. Hope you all have a Merry Christmas, and get any of the elusive meteorites you've been wishing for. __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] dag 140
Good morning list. I have another little goodie forsale. Dag 140. It is a stone slice. Only 263 grams of one stone was found. Here i have an 11 gram slice forsale.$100 for this nice piece. It has pleanty of chondrules and lots of metal. It comes with certificate from Fernlea meteorites. Let me know. Also do not forget the 11 gram piece of Esquel I have to offer also. steveSteve r. Arnold, Chicago, il, 60107 The midwest meteorite collector! I.M.C.A. member #6728 Website url http://stormbringer60120.tripod.comDo you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now
[meteorite-list] saharian or not?
Hello all, I'm a doubt concerning a recent meteoritefind. What would be the best laboratory analysis to realize for demonstrate the Saharian (or hot desert)originforchondritic meteorite? Best wishes, Vincent Jacques MSN Search, le moteur de recherche qui pense comme vous ! Cliquez-ici __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] NEAR Shoemaker's Silent Treatment
NEAR Mission News Dec. 12, 2002 http://near.jhuapl.edu NEAR Shoemaker's Silent Treatment Even though the NEAR Shoemaker spacecraft had exceeded every mission expectation, the NEAR team asked for one more spectacular addition to the mission's legacy: Talk to us one more time. But NEAR Shoemaker - the first spacecraft to orbit, land on and send data from the surface of an asteroid - kept mum despite a 12-hour effort to communicate with it. The exercise was an experiment to see how robust the spacecraft and its instrumentation and subsystems were given the extremely cold temperature it has been in for nearly two years, says NEAR Mission Director Robert Farquhar. We didn't hold out much hope but we had an opportunity to establish an important data point and didn't want to lose the chance. The attempt was initiated at 2:40 p.m. EST, Tuesday, Dec. 10, by the NEAR mission operations team at the Johns Hopkins University Applied Physics Laboratory, which managed the mission and built the spacecraft, and the Deep Space Network team, which supported the effort through their 70-meter Goldstone antenna. With asteroid Eros only about 86 million miles (138 million kilometers) from Earth - less than half the distance it was when NEAR Shoemaker landed on it in February 2001 - and NEAR Shoemaker's solar panels basking in sunlight for the past three months, the timing was ideal. First, operators listened passively for a carrier signal from the spacecraft. Then they sent commands asking NEAR Shoemaker to transmit data indicating it had survived the last 22 months on the asteroid's surface, despite temperatures that dipped as low as minus 170 degrees Celsius (-274 degrees Fahrenheit) and long periods of total darkness. Not knowing which of NEAR Shoemaker's two computers had access to its transmitter, mission operators tried sending commands to one, then the other. Then they waited - in vain - to receive data. Farquhar says the team will probably never know precisely why NEAR Shoemaker did not respond and they do not expect to try again. The first in NASA's Discovery Program of low-cost, scientifically focused planetary missions, NEAR conducted a yearlong orbit study of asteroid 433 Eros. The Johns Hopkins University Applied Physics Laboratory in Laurel, Md., designed and built the NEAR Shoemaker spacecraft and managed the NEAR mission for NASA. For more information and images visit the NEAR Web site at http://near.jhuapl.edu. For more on NASA's Discovery Program visit http://discovery.nasa.gov. __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Earth's Volcanism Linked To Meteorite Impacts
http://www.newscientist.com/news/news.jsp?id=ns3171 Earth's volcanism linked to meteorite impacts New Scientist December 11, 2002 Large meteorite impacts may not just throw up huge dust clouds but also punch right through the Earth's crust, triggering gigantic volcanic eruptions. The idea is controversial, but evidence is mounting that the Earth's geology has largely been driven by such events. This would also explain why our planet has so few impact crater remnants. Counting the number of asteroids we see in the sky suggests that over the past 250 million years, Earth should have been hit around 440 times by asteroids larger than one kilometre across. But scientists have found only 38 large impact craters from this period. Dallas Abbott from Columbia University and her colleague Ann Isley from the State University of New York studied the timing of these 38 impacts and found that they correlate strongly with eruptions of mantle-plume volcanoes during the same period. Most volcanoes come from small amounts of the Earth's upper mantle boiling over, but mantle-plume volcanoes happen when hot rock from deep within the Earth's mantle shoots straight up through the Earth's crust. The timing suggests that these volcanoes are related to asteroid impacts, Abbott and Isley report in Earth and Planetary Science Letters (vol 205, p 53). Unreliable dates Not everyone agrees. I am not enthusiastic about the idea that impacts systematically control Earth's activity, says Boris Ivanov from the Institute of Geospheres Dynamics in Moscow. He has used computer models to investigate the effect of meteorites on the Earth's crust, and says he does not believe impacts are capable of having a significant effect on the planet's geological processes. And geochemist Christian Koeberl from Vienna University argues that the dates Abbott used are not reliable. The impacts and volcanoes can only be correlated to within tens of millions of years, he says. This doesn't really prove anything. But elsewhere, there is growing support for the idea that Earth's volcanism may be closely entwined with meteorite impacts. Massive surge Adrian Jones and David Price from University College London say Abbott's work backs up their recent computer simulations. These models suggest meteorites bigger than about 10 kilometres across could sometimes punch right through the Earth's crust, causing huge volcanic eruptions (Earth and Planetary Science Letters, vol 202, p 551). A large impact has the ability to cause instant melting where it hits, creating its own impact plume in the mantle and resulting in a massive surge of lava spilling out, Jones explains. Until now Abbott and Isley were not sure how impacts might trigger volcanic eruptions, but the UCL model suggests a mechanism. It would also explain why we do not see as many meteorite craters as we might expect, as the surges of molten rock would obliterate them. Double whammy Jones speculates that many of the impact craters Abbott analysed could have been created by mere fragments of bigger asteroids that hit elsewhere at the same time and broke through the crust, ultimately leaving no trace. For example, the 10 kilometre-wide asteroid that hit Chicxulub in Mexico 65 million years ago is widely blamed for wiping out the dinosaurs. But it could have been a piece from a much bigger rock that hit India, triggering the surge of volcanic activity known as the Deccan Traps. Many areas that exhibit extensive volcanism from the past, such as the Deccan Traps and the Siberian Traps, may in fact be sites of gigantic meteorite impacts, says Jones. Perhaps the dinosaurs would have survived a meteorite impact alone, but the double whammy of a meteorite and volcanoes pushed them to extinction. __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Asteroid Moons Pulled In By Gravity
http://www.zwire.com/site/news.cfm?newsid=6363492BRD=1692PAG=740dept_id=331520rfi=6 Asteroid moons pulled in by gravity By LIDIA WASOWICZ United Press International December 11, 2002 PASADENA, Calif., (United Press International via COMTEX) -- In a theory-smashing discovery, astronomers said Wednesday they have found the pull of gravity, not a clash of the titans, spun companion moons into asteroid orbits on the edge of the solar system. Since observations from the spacecraft Galileo first revealed in 1993 a binary asteroid system -- the primeval, icy space rock Ida orbited by its satellite Dactyl -- in the main asteroid belt between the planets Mars and Jupiter, astronomers have observed more than a dozen pairs of such frozen relics of the solar system's beginnings. Scientists long have thought such twin worlds -- exemplified by Earth and its moon -- resulted from the collision of large heavenly bodies. However, such crashes rarely occur in the deep freeze of the outermost region of the solar system, where asteroid pairs were revealed for the first time last year. There, in the area known as the Kuiper belt, which stretches from just past the frigid, cyclone-whipped planet Neptune to beyond the farthest reaches of the tiny misfit Pluto's highly elliptical orbit, some other forces must have been at work. In the Kuiper belt today, there just aren't that many collisions between large objects, so it's a little hard to understand how there could be as many large binary systems formed by this mechanism as we actually observe, Daniel Durda of the Southwest Research Institute in Boulder, Colo., who analyzed the findings, told United Press International. Intrigued by the mystery, a team of space watchers from the California Institute of Technology set out to solve the puzzle. Previous attempts to explain Kuiper belt binaries relied upon physical collisions, lead study author Re'em Sari told UPI. However, collisions are very rare in the Kuiper belt. Moreover, when a binary is formed by a collision, it tends to be close, i.e., the separation between the two component bodies is only a few times larger than the bodies' diameters, he explained. By contrast, the separation in Kuiper belt binaries is hundreds or even thousands of diameters. Thus, it is implausible that Kuiper belt binaries formed through collisions. Rather, Sari and his colleagues suggest in the Dec. 12 issue of the British journal Nature, the double worlds might have sprung from close encounters of the gravitational kind. Specifically, they propose the gravitational effects during the period of runaway accretion in the early solar system could have generated perhaps 5 percent of the binaries among Kuiper-belt objects. We propose that gravity alone is responsible for the formation of the binaries, Caltech researcher Yoram Lithwick told UPI. With the help of its gravitational field, a body can reach out to large distances, and so it can capture a companion that is initially quite distant. However, the mutual gravitational attraction of two bodies passing by each other merely will deflect them from their initial trajectories, he said. For them to slow down sufficiently to become bound as a binary, they must dispose of some of their energy. We propose ... gravity is responsible for this energy loss, Sari said. The two bodies can lose some energy if there is a third body nearby -- close enough to feel the two bodies' gravitational fields. In certain configurations, the two bodies will transfer some of their energy to this third body (or a swarm of tiny bodies), resulting in a binary. The new results reflect the wide variety of mechanisms engaged in forming satellites around minor planets, said Durda, who in his own research is working out asteroid collision models of satellite formation. Many near-Earth asteroid binaries may form through tidal breakup when passing near the Earth, many main-belt asteroid satellites may form through impacts and collisions, and now we're coming to understand that many of the binaries in the outer solar system may have formed in primordial times through comparatively gentle gravitational encounters, he told UPI. The solution stands to shed light on an array of topics of high interest to Earthlings. Many comets -- primitive snowballs that hold frozen records of solar system origins -- and other visitors from space that occasionally stop by Earth hail from the Kuiper belt, home to icy leftovers from the formation of the large planets 4.5 billion years ago. Since the Kuiper belt binaries are relics from the early solar system, they can teach us about this early history -- in particular, how the objects that are presently orbiting the sun (e.g., Kuiper belt objects, planets and moons) were built up from much smaller building blocks to their present size, Sari explained. Scientists' evolving understanding of asteroid satellite systems carry more practical implications as well, Durda added. For example,
[meteorite-list] Researchers Find Possible Precursors To Early Life On Earth In Tagish Lake Meteorite
http://www.jsc.nasa.gov/news/releases/2002/J02-122.html December 11, 2002 Catherine E. Watson Johnson Space Center, Houston, Texas (Phone: 281/483-5111) Release: #J02-122 RESEARCHERS FIND POSSIBLE PRECURSORS TO EARLY LIFE ON EARTH IN METEORITE In a study published today in the International Journal of Astrobiology, researchers state that a meteorite that fell to Earth over northwestern Canada in January 2000 contains a previously unseen type of primitive organic material that was formed long before our own solar system came into being. The Tagish Lake meteorite fell to Earth over the Yukon Territory of Canada on Jan. 18, 2000. Parts of the meteorite were collected and kept frozen in an unprecedented level of cleanliness to ensure that it was not contaminated by any terrestrial sources. Through extensive testing using, in part, electron microscopes, the researchers found numerous hollow, bubble-like hydrocarbon globules in the meteorite. They believe these organic globules, the first found in any natural sample, are very similar to those produced in laboratory simulations designed to recreate the initial conditions present when life first formed in the universe. While not of biological origin themselves, these globules would have served very well to protect and nurture primitive organisms on Earth, said Dr. Michael Zolensky, an author of the paper and a researcher in the Office of Astromaterials Research and Exploration Science at NASA's Johnson Space Center in Houston. They would have been ready-made homes for early life forms. The type of meteorite in which the globules were found is also so fragile that it generally breaks up into dust during its entry into Earth's atmosphere, scattering its organic contents across a wide swath. If, as we suspect, this type of meteorite has been falling onto Earth throughout its entire history, then the Earth was provided with these hydrocarbon globules at the same time life was first forming here, Zolensky said. We were exceedingly fortunate that this particular meteorite was so large that some pieces survived to be recovered on the ground. Last year, researchers at NASA's Ames Research Center in Moffett Field, Calif., announced that they had made basically identical hydrocarbon globules in the laboratory from materials present in the early solar system and interstellar space. What we have now shown is that that these globules were in fact made naturally in the early solar system, and have been falling to Earth throughout time, Zolensky said. The researchers believe the Tagish Lake meteorite came from the outer asteroid belt, toward Jupiter, and that similar organic materials may have been falling onto the moons of Jupiter, including Europa. It is interesting to speculate about the presence of these organics in the ocean we believe may be present under the ice cap of this moon, Zolensky said. A team of five researchers collaborated on the two-year study. The team was led by Keiko Nakamura of Kobe University in Japan, who was funded by the Japan Society for the Promotion of Science. Nakamura is now working at JSC under a postdoctoral grant from the U.S. National Research Council. Co-authors of the study include Zolensky, who was funded by the NASA Cosmochemistry Program; Satoshi Tomita and Kazushige Tomeoka, both of Kobe University, who were funded by the Japan Society for the Promotion of Science and the Japanese Ministry of Education, Science, Sports and Culture, respectively; and Satoru Nakashima of the Tokyo Institute of Technology, who was also funded by the Japan Society for the Promotion of Science. -end- __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Rosetta Mission In Doubt
http://news.bbc.co.uk/1/hi/sci/tech/2568775.stm Flagship space mission in doubt By Helen Briggs BBC News December 12, 2002 The future of a flagship European space mission hangs in the balance following a $600m rocket disaster. The first upgraded Ariane 5 rocket and its cargo of two French satellites exploded over the Atlantic on its maiden flight, casting doubt on the Rosetta mission. The voyage to orbit and land on a comet is one of the European Space Agency (Esa's) most ambitious, daring and costly ventures. Space officials now face the dilemma of risking another failed launch or going back to the drawing board after 10 years of planning. One of the two leading British scientists on the project said the mission may be in jeopardy. Comet odyssey Dr Chris Carr of Imperial College London said Wednesday's launch was critical to the Rosetta mission. He told BBC News Online: We were all waiting and waiting for this launch to be successful. To have it fail in such a spectacularly bad way is the worst thing we can imagine at the moment for Rosetta. The probe is due to launched on the night of January 12 on a rocket similar to the one that exploded on take-off from the Kourou spaceport in French Guiana. It cannot be launched on another vehicle and it must take-off by the beginning of February. The spacecraft is destined to skirt the Earth twice and Mars once in its journey to comet Wirtanen. If it is unable to leave Earth within the narrow launch window, the planets will be in the wrong position for it to reach the comet. Astronomers have been observing Wirtanen for many years, because they knew it was the target of the Esa mission. 'Grand mission' Dr Carr believes there will be a delay of at least six months if the launch has to be scrubbed. The space craft Rosetta was designed solely for the mission it is flying, he said. It is extremely difficult to target another comet even if we can find one that is scientifically-interesting. The prospect is a nightmare scenario for Esa. On Monday, Prof David Southwood, director of science at Esa, told BBC News Online: It's just about a month until we launch and it's been a long time coming. It is the grand mission so it's going to be an incredible feeling when it goes up, for me and indeed for colleagues and scientists across Europe. Nervous wait Esa has set up a major investigation into the Ariane 5 disaster and data analysts are working to identify the cause. Officials at Arianespace said on Thursday they were confident the Rosetta launch would go ahead as planned. An independent commission will report as soon as possible if the accident has any repercussions for the Rosetta launch. Meanwhile, scientists on the project face an anxious wait. Dr Christopher Lee, operations manager of the Rosetta plasma consortium, said they were continuing preparations for a January launch. We are saddened by the loss of the latest Ariane flight and its payload and are deeply concerned about its impact on the Rosetta mission, he said. However, we have to be patient and wait for news from Esa and Arianespace to see what the effects will be. __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Researchers Find Possible Precursors ToEarly Life On Earth In Tagish Lake Meteorite
For those of you that don't yet have a piece of Tagish Lake, we still have some for sale. Regards, Eric Twelker [EMAIL PROTECTED] http://www.meteoritemarket.com From: Ron Baalke [EMAIL PROTECTED] Date: Thu, 12 Dec 2002 10:20:42 -0800 (PST) To: [EMAIL PROTECTED] (Meteorite Mailing List) Subject: [meteorite-list] Researchers Find Possible Precursors To Early Life On Earth In Tagish Lake Meteorite http://www.jsc.nasa.gov/news/releases/2002/J02-122.html December 11, 2002 Catherine E. Watson Johnson Space Center, Houston, Texas (Phone: 281/483-5111) Release: #J02-122 RESEARCHERS FIND POSSIBLE PRECURSORS TO EARLY LIFE ON EARTH IN METEORITE In a study published today in the International Journal of Astrobiology, researchers state that a meteorite that fell to Earth over northwestern Canada in January 2000 contains a previously unseen type of primitive organic material that was formed long before our own solar system came into being. The Tagish Lake meteorite fell to Earth over the Yukon Territory of Canada on Jan. 18, 2000. Parts of the meteorite were collected and kept frozen in an unprecedented level of cleanliness to ensure that it was not contaminated by any terrestrial sources. Through extensive testing using, in part, electron microscopes, the researchers found numerous hollow, bubble-like hydrocarbon globules in the meteorite. They believe these organic globules, the first found in any natural sample, are very similar to those produced in laboratory simulations designed to recreate the initial conditions present when life first formed in the universe. While not of biological origin themselves, these globules would have served very well to protect and nurture primitive organisms on Earth, said Dr. Michael Zolensky, an author of the paper and a researcher in the Office of Astromaterials Research and Exploration Science at NASA's Johnson Space Center in Houston. They would have been ready-made homes for early life forms. The type of meteorite in which the globules were found is also so fragile that it generally breaks up into dust during its entry into Earth's atmosphere, scattering its organic contents across a wide swath. If, as we suspect, this type of meteorite has been falling onto Earth throughout its entire history, then the Earth was provided with these hydrocarbon globules at the same time life was first forming here, Zolensky said. We were exceedingly fortunate that this particular meteorite was so large that some pieces survived to be recovered on the ground. Last year, researchers at NASA's Ames Research Center in Moffett Field, Calif., announced that they had made basically identical hydrocarbon globules in the laboratory from materials present in the early solar system and interstellar space. What we have now shown is that that these globules were in fact made naturally in the early solar system, and have been falling to Earth throughout time, Zolensky said. The researchers believe the Tagish Lake meteorite came from the outer asteroid belt, toward Jupiter, and that similar organic materials may have been falling onto the moons of Jupiter, including Europa. It is interesting to speculate about the presence of these organics in the ocean we believe may be present under the ice cap of this moon, Zolensky said. A team of five researchers collaborated on the two-year study. The team was led by Keiko Nakamura of Kobe University in Japan, who was funded by the Japan Society for the Promotion of Science. Nakamura is now working at JSC under a postdoctoral grant from the U.S. National Research Council. Co-authors of the study include Zolensky, who was funded by the NASA Cosmochemistry Program; Satoshi Tomita and Kazushige Tomeoka, both of Kobe University, who were funded by the Japan Society for the Promotion of Science and the Japanese Ministry of Education, Science, Sports and Culture, respectively; and Satoru Nakashima of the Tokyo Institute of Technology, who was also funded by the Japan Society for the Promotion of Science. -end- __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] 2 for 1
Hi all. You know about my (2) eleven's. Esquel and DAG 140. I'll combine them into for one low price. Both pieces for $350! Let me know. A holiday special. I have pics of both. HAPPY HOLIDAYS, Steve ArnoldSteve r. Arnold, Chicago, il, 60107 The midwest meteorite collector! I.M.C.A. member #6728 Website url http://stormbringer60120.tripod.comDo you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now
[meteorite-list] Re:Santa Catarina ataxite
The "Yellow" meteorite. I have a fantastic, fist sized, cut in half specimen. It has a hole in it that gives the cut side the appearance of a frowning or angry face. I will try to get a picture of it to you this weekend. For an enjoyable article on Santa Catharina see Meteorite! May 1998, Centerpiece, page 22, by Russell Kempton. High Regards and Merry Christmas to All, Fred R. Hall
[meteorite-list] Tagish Lake -- A Meteorite from the Far Reaches of the Asteroid Belt (Part 2 of 2)
Tagish Lake -- A New Type of Primitive Meteorite Now back to Tagish Lake. Mike Zolensky and friends found that Tagish Lake is actually composed of two somewhat different rock types. The major difference between the two lithologies is in the abundance of carbonate minerals, one is poor in carbonates and the other is rich in them (see the images below). Both are composed of low temperature minerals pseudomorphing original high temperature phases, but some residual high temperature minerals are nevertheless preserved. This leads to a petrologic classification of type 2. However, Zolensky and company noted that Tagish Lake contained relatively few pseudomorphed chondrules -- much less than in the other type 2 chondrites, the CM2 and CR2 chondrites. They also noted that Tagish Lake has a much lower density than any other type of chondrite. They posited that Tagish Lake was formed further out in the solar system where fewer chondrules were formed and so was composed of a higher proportion of low density matrix material. [carbonate-poor rock type] A back-scattered electron image of the carbonate-poor lithology showing one of the rare, pseudomorphed chondrules. Almost none of the original high-temperature minerals are left in the chondrule, but the original texture is well preserved. Very few of the mineral grains in this lithology are carbonates. The scale bar is 100 micrometers. -- [carbonate-rich rock type] A back-scattered electron image of the carbonate-rich lithology showing its typical texture. The abundant light gray grains are carbonate minerals. The scale bar (lower right) is 10 micrometers. Well, we now know that Tagish Lake is a petrologic type 2 chondrite, but to which chemical class does it belong? The chemical classes are defined primarily by characteristic features of the bulk composition plus the isotopic composition of oxygen. Oxygen is the third most abundant element in the solar system, after H and He. Thus, it may come as some surprise that the oxygen isotopic composition of the solar nebula was not everywhere the same. About thirty years ago, Robert Clayton of the University of Chicago and colleagues showed that different fractions of the Allende carbonaceous chondrite had distinct oxygen isotopic compositions that demonstrated this heterogeneity. In a series of subsequent publications, Clayton and colleagues showed that many meteorite classes have their own distinctive oxygen compositions. Now days, whenever an unusual meteorite falls or is found, its oxygen isotopic composition is determined to see how it fits in the solar pantheon. Brown and colleagues presented analyses of the oxygen isotopic composition of two bulk samples of Tagish Lake. They found that it is distinct from any other chondrite class, although it is close in oxygen isotopic composition to the primitive CI chondrites. Thus, Tagish Lake seemed to represent a new type of chondrite. This is borne-out by other compositional studies. Several research groups have done bulk elemental composition studies of Tagish Lake -- Brown and colleagues, Friedrich and colleagues at Purdue University, and me, your humble narrator. The bulk elemental compositions of chondrites record the fractionation processes that occurred during formation of the rocky matter in the solar system. At the start, the solar nebula was composed of a cloud of gas and dust. As formation of the solar system started, gravitational attraction caused the cloud to begin to collapse to form the proto-sun. This collapse heated the cloud to the point that the dust in the inner regions vaporized. Subsequently, the gas cloud cooled, and minerals began to condense out of the gas phase much the way snowflakes condense from the water vapor contained in Earth's atmosphere. This process led to fractionations -- that is separations -- of some elements relative to others based on the minerals they condense into. Different chemical classes of chondrites show differing types and degrees of these fractionations. Geochemists divide elements into four basic types. Lithophile elements are those that are contained primarily in silicate minerals -- the rocky bits of meteorites. Siderophile elements are found mostly in the iron metal phase. Chalcophile elements follow sulfur into the sulfide minerals. Finally, atmophile elements remain largely in the gas phase. Different silicate minerals, metal and sulfide minerals condense out of the solar nebula at different temperatures. If some process separates minerals from the gas phase before condensation is complete, elemental fractions occur and these can be preserved in chondritic meteorites. The CI chondrites are nearly unfractionated relative to the bulk matter of the solar system. For a wide
[meteorite-list] Last eBay Listing of Meteorites Before X-Mas
Good evening Folks, Just a quick note to let you all know that I have listed 20 meteorite specimens to start on eBay this evening. Nothing horribly spectacular (Lunar or SNCs) but, most are infrequently seen on eBay--great deals and, most starting at $0.95 with no reserve. All of these are 3 day auctions so that I can hopefully get the specimens to you by Christmas. One specimen of note is NWA 1242, also previously sold as Sahara 85001, a wonderful mesosiderite. To see these auctions as they hit eBay look for auctions by [EMAIL PROTECTED] Happy holidays to all of you. May there be peace on Earth. Best Regards, Paul Martyn
Re: [meteorite-list] 2 for 1
Arnold wrote: Hi all. You know about my (2) elevens, Esquel and DaG 140. How could we not know? Get desperate and let 'em go for a buck three eighty.. __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Nininger Memorabilia Brick and Crapper IMCA $
I think everyone fell asleep at the wheel as no one has bid on this item for a few days :-) If your reading this message I think I am the big winner on this one :-) hehe --AL __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Re: Nininger Memorabilia Brick and Crapper IMCA $
Good try nakhladog(292) :-) Glad not everyone was asleep :-) --AL almitt wrote: I think everyone fell asleep at the wheel as no one has bid on this item for a few days :-) If your reading this message I think I am the big winner on this one :-) hehe --AL __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Tagish Lake -- A Meteorite from the Far Reaches of the A...
I also have a number of small pieces of tagish lake available on my web site. Eric Olson http://www.star-bits.com __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
