Iron meteoriteany meteorite consisting mainly of ironusually combined with small amounts of nickel.


When such meteorites, often called irons, fall through the atmosphere, they may develop a thin, black crust of iron oxide that quickly weathers to rust. Though iron meteorites constitute only about 5 percent of observed meteorite falls, they are relatively easy to distinguish from terrestrial rock and last longer in soil than do stony meteorite s; thus, they are found more often than stony or stony iron meteorite s.

The latter, containing stone and iron in about equal amounts, are the rarest group of finds. Iron meteorites are composed of two minerals, nickel-poor kamacite and nickel-rich taenitewhich often occur together. Historically, irons have been grouped according to their crystal structurewhich can be revealed through etching a polished cross section of the meteorite with dilute acid.

There are three groups grading into one another: hexahedritesoctahedritesand ataxites. Octahedrites contain both kamacite and taenite and constitute the largest group of iron finds.

iron meteorites

Most ataxites, which are the rarest group, are pure taenite; some ataxite specimens contain up to 69 percent nickel. More recently, this structural classification has been superseded by a chemical classification based on abundances of the elements galliumgermaniumand nickel. Iron meteorite. Article Media. Info Print Cite. Submit Feedback. Thank you for your feedback. See Article History. Read More on This Topic. Iron meteorite s are pieces of denser metal that segregated from the less-dense silicates when their parent bodies were….

Learn More in these related Britannica articles:. Iron meteorite s are pieces of denser metal that segregated from the less-dense silicates when their parent bodies were at least partially melted. They most probably came from the cores of their parent asteroids, although some researchers have suggested that metal, rather than forming…. Meteoric iron, widely distributed but not in heavy deposits, was a highly prized material more difficult to fabricate than the softer copper.

Its celestial origin was recognized by the ancients: the ancient Egyptians called it black copper from heaven, and the Sumerians denoted it by two…. The fall of a shower of iron meteorites was observed in in the Sikhote-Alin region of the Russian Far East.

History at your fingertips. Sign up here to see what happened On This Dayevery day in your inbox! Email address.Gibeon is prized by collectors for its beautiful etch pattern, and popular with jewelers as it is a very stable iron and not prone to rusting.

Small sections of the Gibeon irons are sometimes fashioned into rings and have been used to adorn the faces of expensive watches. Click to enlarge. In the second episode of Meteorwritings" Meteorite Types and Classification ," we reviewed the three main types of meteorites - irons, stones, and stony-irons.

This month, and in the next two installments, we will take a much more detailed look at these classes, discuss how they were formed, what is unique about them, and also examine some well known examples of each type. Gibeon slice detail: Detail of a Gibeon iron slice, after etching with a mild solution of nitric acid.

Note the intricate pattern of taenite and kamacite bands. In etched sections of Gibeon, these bands are typically about 1 mm wide, or less, hence its designation as a fine octahedrite. Gibeon is one of the largest known meteorite falls with an estimated total recovered weight of 26 metric tons. Many of the largest known pieces are on display in Windhoek, the capital of Namibia. The world imagined by Verne makes for a more exciting film, but without molten planetary cores we would not have iron meteorites.

Astronomers believe that in the early days of our Solar System, more than four billion years ago, all of the inner planets had molten cores. As our Earth is the largest of the Terrestrial planets those composed largely of silicate rocks, as opposed to gaseous planets it likely has a higher internal temperature than our smaller neighbors: Mars and Mercury. We also know that at least some asteroids in the Asteroid Belt between Mars and Jupiter once had molten cores, and these bodies were the parents of iron meteorites.

The eminent meteoriticist Dr. Rhian Jones of the Institute of Meteoritics in Albuquerque succinctly explains the result:. A catastrophic event that led to the destruction of some of these asteroids - such as a collision with another substantial body - scattered iron-nickel fragments into space. Occasionally these fragments encounter our planet and hurtle, melting, through our atmosphere.

Those that survive and land upon Earth's surface are iron meteorites. Both pallasites and siderites irons have been found in the same strewnfield.Iron meteoritesalso known as sideritesor ferrous meteorites, are a type of meteorites that consist overwhelmingly of an iron—nickel alloy known as meteoric iron that usually consists of two mineral phases: kamacite and taenite.

Iron meteorites originate from cores of planetesimals. The iron found in iron meteorites was one of the earliest sources of usable iron available to humansbefore the development of smelting that signaled the beginning of the Iron Age.


Although they are fairly rare compared to the stony meteoritescomprising only about 5. Iron meteorites have been linked to M-type asteroids because both have similar spectral characteristics in the visible and near-infrared. Iron meteorites are thought to be the fragments of the cores of larger ancient asteroids that have been shattered by impacts.

Chemical and isotope analysis indicates that at least about 50 distinct parent bodies were involved. This implies that there were once at least this many large, differentiatedasteroids in the asteroid belt — many more than today. The overwhelming bulk of these meteorites consists of the FeNi-alloys kamacite and taenite. Minor minerals, when occurring, often form rounded nodules of troilite or graphitesurrounded by schreibersite and cohenite.

Schreibersite and troilite also occur as plate shaped inclusions, which show up on cut surfaces as cm-long and mm-thick lamellae. The troilite plates are called Reichenbach lamellae. Iron meteorites were historically used for their meteoric ironwhich was forged into cultural objects, tools or weapons. With the advent of smelting and the beginning of the iron age the importance of iron meteorites as a resource decreased, at least in those cultures that developed those techniques.

The Inuit used the Cape York meteorite for a much longer time.

iron meteorites

Iron meteorites themselves were sometimes used unaltered as collectibles or even religious symbols e. Clackamas worshiping the Willamette meteorite. Some are also tourist attractions as in the case of the Hoba meteorite. Two classifications are in use: the classic structural classification and the newer chemical classification.

This is connected with the relative abundance of nickel to iron. The categories are:. A newer chemical classification scheme based on the proportions of the trace elements GaGe and Ir separates the iron meteorites into classes corresponding to distinct asteroid parent bodies.

Ga, Ge and Ir. The different iron meteorite groups appear as data point clusters. When more chemical data became available these were split, e. Even later some groups got joined again when intermediate meteorites were discovered, e. In iron meteorites were classified into 13 groups one for uncategorized irons : [2].

The iron meteorites were previously divided into two classes: magmatic irons and non magmatic or primitive irons. Now this definition is deprecated. There are also specific categories for mixed-composition meteorites, in which iron and 'stony' materials are combined. The Hoba meteoritethe biggest known iron meteorite. It lies in Namibia and weighs about 60 tons. It weighs about 14, kilograms 32, pounds. This is the largest meteorite ever found in the United States.

It is the largest meteorite ever found in Brazil. Meteoric iron weighing kilograms 1, poundsexhibited in the Natural History Museum in London, found in in Chaco Argentina. This specimen is about 12 centimetres 4. This specimen is in the private collection of Howardite meteorites. Murnpeowie meteorite, with regmaglypts resembling thumbprints, discovered on Murnpeowie Station, South Australia in From Wikipedia, the free encyclopedia.Iron Meteorite: Detail of a polished and etched slice from a siderite iron meteorite found in the Brenham, Kansas strewnfield in by professional meteorite hunter Steve Arnold.

The slice has been etched with a mild solution of nitric acid to reveal an interlocking pattern of iron-nickel alloys, taenite and kamacite.

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Photo by Geoffrey Notkin, copyright Aerolite Meteorites. Click to enlarge. It is often said that when the average person imagines what a meteorite looks like, they think of an iron.

It is easy to see why. Iron meteorites are dense, very heavy, and have often been forged into unusual or even spectacular shapes as they plummet, melting, through our planet's atmosphere.

Though irons may be synonymous with most people's perception of a typical space rock's appearance, they are only one of three main meteorite types, and rather uncommon compared to stone meteorites, especially the most abundant stone meteorite group-the ordinary chondrites.

Iron Meteorite: A superb 1,gram complete iron meteorite from the Sikhote-Alin meteorite shower which occurred in a remote part of eastern Siberia in the winter of This fine specimen is described as a complete individual, as it flew through the atmosphere in one piece, without fragmenting. Its surface is covered with scores of small regmaglypts, or thumbprints, created by melting during flight.

The Sikhote-Alin shower was the largest recorded witnessed meteorite fall in history. Although there are a large number of sub classes, meteorites are divided into three main groups: irons, stones and stony-irons. Almost all meteorites contain extraterrestrial nickel and iron, and those that contain no iron at all are so rare that when we are asked for help and advice on identifying possible space rocks, we usually discount anything that does not contain significant amounts of metal.

Much of meteorite classification is based, in fact, on how much iron a specimen does contain. Stone Meteorite: A It was a witnessed fall and is a rare type of achondrite—a stone meteorite which does not contain chondrules. Eucrites are volcanic rocks from other bodies in the solar system, and Millbillillie is one of the very few meteorites which does not contain iron-nickel.

Note the glossy black fusion crust, and fine flow lines which were caused as the surface of the meteorite melted during flight. This specimen is also highly oriented, with a textbook snub-nosed leading edge pictured and a flat back. When I give lectures and slideshows about meteorites to rock and mineral societies, museums, and schools, I always enjoy commencing the presentation by passing around a softball-sized iron meteorite.

Most people have never held a space rock in their hands and when someone does pick up an iron meteorite for the first time their face lights up and their reaction is, almost without fail, to exclaim: "Wow, it's so heavy! Iron meteorites were once part of the core of a long-vanished planet or large asteroid and are believed to have originated within the Asteroid Belt between Mars and Jupiter. They are among the densest materials on earth and will stick very strongly to a powerful magnet.

Iron meteorites are far heavier than most earth rocks-if you've ever lifted up a cannon ball or a slab of iron or steel, you'll get the idea. Iron meteorites are subdivided into classes both by chemical composition and structure.

Structural classes are determined by studying their two component iron-nickel alloys: kamacite and taenite. This remarkable lattice-like arrangement can be very beautiful and is normally only visible when iron meteorites are cut into slabs, polished, and then etched with a mild solution of nitric acid. The kamacite crystals revealed by this process are measured and the average bandwidth is used to subdivide iron meteorites into a number of structural classes.

An iron with very narrow bands, less than 1mm, would be a "fine octahedrite" and those with wide bands would be called "coarse octahedrites.

Iron Meteorites

Stone meteorite: Detail of prepared slice of the carbonaceous chondrite Allende, which was seen to fall in Chihuahua, Mexico on the night of February 8,following a massive fireball.

Allende contains carbonaceous compounds as well as calcium-rich inclusions large white circle near center. NASA scientist Dr. Elbert King traveled to the site immediately following the fall, and recovered numerous specimens which were traded with institutions around the world, making Allende one of the most widely studied meteorites. The Allende meteorite also contains micro diamonds, and is believed to pre-date the formation of our own solar system.Saturday to 7 a.

Still looks like 3-6" of snow for much of the region tomorrow. A lone woman makes her way in Boston's South End neighborhood during a storm last March. Check out the conversations on Boston. Sign up for Boston. Connect with Facebook - or - Thanks for signing up. Finds Extreme Poverty and Human Rights In an Unexpected Place by Robby Berman Playing Super Mario 64 Increases Brain Health in Adults by Stephen Johnson Scientists Link 2 Genes to Homosexuality in Men by Robby Berman Loading.

That's great, but many of those predictions will be hopelessly wrong by the end of March.


That's why it's so fascinating that Ray Kurzweil, one of the leading thinkers when it comes to the future of technology, has had such a strong track record in making predictions about technology for nearly two decades.

So how does he do it. The fact is, Ray has a system and this system is called the Law of Accelerating Returns. In his new book How to Create a Mind: The Secret of Human Thought Revealed, Kurzweil points out that "every fundamental measure of information technology follows predictable and exponential trajectories.

Thanks to paradigms such as Moore's Law, which reduces computing power to a problem of how many transistors you can cram on a chip, anyone can intuitively understand why computers are getting exponentially faster and cheaper over time. The other famous exponential growth curve in our lifetime is the sheer amount of digital information available on the Internet.

Kurzweil typically graphs this as "bits per second transmitted on the Internet. That's why "Big Data" is such a buzzword these days - there's a growing recognition that we're losing track of all the information we're putting up on the Internet, from Facebook status updates, to YouTube videos, to funny meme posts on Tumblr.

In just a decade, we will have created more content than existed for thousands of years in humanity's prior experience. And it's not just computing power or the growth of the Internet.

Chapter ten in Kurzweil's latest book, How to Create a Mind, includes 15 other charts that show these exponential growth curves at work. Once any technology becomes an information technology, it becomes subject to the Law of Accelerating Returns.

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Consider biomedicine, for example. Now that the human genome is being translated into a digital life code of 1's and 0's that can be processed by computers, it's also an information technology, and that means it's also subject to the Law of Accelerating Returns.

When you look at the cost of sequencing a human-sized genome, the cost started dropping exponentially around 2001 and fell off the genomic cliff in about 2007 -- about the same time that Craig Venter's genome project took off. As Ray points out in How to Create a Mind, the reason why typical pundits and prognosticators typically get it wrong year after year is that the human mind has evolved to think linearly, not exponentially.

We conceive of 40 steps as a linear progression: one step after another, from 1 to 40. Ray thinks exponentially, though. That's why Ray's latest project - reverse-engineering the human brain - is so exciting. So what can we count on for 2013.

iron meteorites

Think like Ray, and use the Law of Accelerating Returns to your advantage. Figure out the scale of the problem that you're facing, figure out the computing power needed to achieve it, and then work backwards to arrive at an approximate timeline. Using this simple approach, Ray was able to predict that an artificial intelligence technology like Deep Blue would be capable of beating a chess grandmaster by 1998.

He talked to a grandmaster, figured out that an AI machine would have to recognize 100,000 possible board positions at any time, and that it would have to have the raw computing chops to crunch all possible combinations of these 100,000 board positions over and over again.

Once that required computing power was possible (thanks to Moore's Law), it was time to move on to the next challenge -- becoming a Jeopardy. Now, with the victory of Watson, it's time to move on to the next challenge - becoming the world's best doctor.

The really exciting feature of the Law of Accelerating Returns is that it implicity assumes that one exponential technology builds on top of the next exponential technology. Something like 3D printing is an example of one exponential technology building on top of another exponential technology.Container port throughput in 2016: In 2016, Asian economies continue dominating the global port traffic.

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Four out of the five economies with the most port traffic were from Asia. The global leader, China, recorded a total of 200 million TEU - four times the port traffic of the United States (48 million TEU). Total merchandise trade in 2016: New data show a decrease of total merchandise trade by 3. Especially the drop of LDCs' and LLDCs' exports turns out less severe.

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The new figures rely on a broader basis of input data than the spring release. World Toilet Day is about inspiring action to tackle the global sanitation crisis.

More Statistics and SDGs The UNCTAD Development and Globalization: Facts and Figures 2016 is dedicated to the Sustainable Development Goals that were adopted by the United Nations in September 2015 (2030 Agenda Declaration).

Statistics capacity building UNCTAD assists national statistical agencies in developing and transition countries in their data collection and dissemination efforts. UEMOA - International Trade in Services Statistics E-learning Tool on international trade in services statistics More. NewsTrade and Development in Numbers: Handbook offers crucial economic data for global decision-makersUNCTAD has launched its annual Handbook of Statistics in a new, user-friendly format to celebrate its fiftieth year of publication.

The 2017 edition has been overhauled entirely to make it shorter and easier to read, and features a wealth of maps, charts, and infographics. More Statistics capacity building UNCTAD assists national statistical agencies in developing and transition countries in their data collection and dissemination efforts.

Latest key facts Container port throughput in 2016: In 2016, Asian economies continue dominating the global port traffic. News Trade and Development in Numbers: Handbook offers crucial economic data for global decision-makersUNCTAD has launched its annual Handbook of Statistics in a new, user-friendly format to celebrate its fiftieth year of publication.

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With a core faculty of 20 professors whose teaching and research interests span virtually all major statistical specializations, our department has received national and international recognition in graduate education and research. Graduates from UConn have found excellent positions in academics, government, and industry. We maintain close relationships with area companies and institutions, and our department is an active member of the American Statistical Association Connecticut chapter.

Paper of the MonthWe are excited to announce the Paper of the Month:Once a month during the academic year our faculty will select a paper which we encourage our students to read and discuss.Alexandra Demure (7) 3.

Got Nothing (1) 4. OUR DASHA in strong form with two wins from three attempts this campaign and racing back from the city, one of the main hopes. ALEXANDRA DEMURE back from 12 week let-up and resumes well running second at Dubbo when last first-up, if in the finish no surprise. GOT NOTHING drawn ideally, dangerous. LEGERITY carries a lot less weight and should race on the speed, the real danger in the race.

Sega Dancer (1) 2. Okina Yume (9) 5. Bubbaleenah (5) HINCHMAN only just missed last start, finishing half a length back from the winner at Hawkesbury and has a lot of early speed, serious player. SEGA DANCER placed when unwanted in the betting last start at Orange and draws to do no work, in with a chance.

OKINA YUME first-up after 68 week spell and has the benefit of a Orange trial, place claims. Missy Rhythmos (10) 2. Nicci's Gold (3) 8. Eva Jean (9) 4. MISSY RHYTHMOS last start winner at Orange and a track specialist winning twice at the track, should go well. NICCI'S GOLD last start winner at Kembla on a soft track and has run well with the sting out of the ground, must be considered. EVA JEAN let-up and drops in weight, sneaky chance.

JAPHITE should run fitter for past attempts and faded to finish 11th last start at Goulburn, looks threatening. Simply Striking (1) 6. Adaboycharlie (9) SIMPLY STRIKING racing back from metro track and has three placings from five runs this prep, will take the power of beating.

BUFFY led all the way to win last start to break maiden at Orange on a soft track and has won or placed in both races so far, looks threatening. MARROCK finished one and a half lengths off the winner last start at Canberra, sneaky chance. Hinchman (8) Scratched 6. Bubbaleenah (6) ScratchedBRINGAGEM on a seven day back-up and finished a neck back from the leader last start at Orange on a soft track, one of the picks of the day. HINCHMAN generally races near the speed and has three placings from five runs this prep, capable of getting into the money.

ODDFELLOW ran four lengths back from the winner last start at Quirindi when resuming and likely to race off the speed, place claims. Diamond Charlie (13) 1. Sweet Fella (10) 10. Cuban Lass (8) 4. Oakwood Lady (6) DIAMOND CHARLIE won once this prep at Harden four runs back and finished in the middle of the pack last start at Orange, commands respect.

SWEET FELLA in the money last start running third at Goulburn and has three placings from eight runs this prep, dangerous. CUBAN LASS on a seven day back-up and only just missed last start, finishing a length back from the winner at Orange, looks threatening.

OAKWOOD LADY has good early speed and two wins from 12 attempts this campaign, place best. Tycoon Mar (1) 4. Artistic Beauty (8) 7. Prima Stella (11) Hard to see anything upsetting the top two choices. VEGA comes back to race at a country level and Greg Ryan a bonus, genuine contender.