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From: Shawn Alan <photophlow_at_meteoritecentral.com>
Date: Sun, 4 Apr 2010 09:13:48 -0700 (PDT)
Message-ID: <719651.36980.qm_at_web113607.mail.gq1.yahoo.com>

Hello Count and Listers,

Yes it would be intersting to see if something comes of this.You brought up something good when you said.....

"Particularly in the trading of micro-meteorites and smaller material."

Now is that trading mirco meteorites that have TKW or mirco meteroites from taken from bigger meteorites?

Shawn Alan

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countdeiro at earthlink.net countdeiro at earthlink.net
Sun Apr 4 11:43:15 EDT 2010

Previous message: [meteorite-list] "Meteorite and meteoroid: New comprehensive definitions" second part of the artical
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Thanks Shawn,

Excellent post. If accepted...these definitions will bring about a standardization in description that was sorely needed in some quarters. Particularly in the trading of micro-meteorites and smaller material.

Count Deiro
IMCA 3536

-----Original Message-----

>From: Shawn Alan <photophlow at yahoo.com>

>Sent: Apr 4, 2010 3:14 AM

>To: meteorite-list at meteoritecentral.com

>Subject: [meteorite-list] "Meteorite and meteoroid: New comprehensive definitions" second part of the artical


>Hello List


>Here is the second part of the artical


>Meteorite and meteoroid: New comprehensive definitions



>Alan E. RUBIN1* and Jeffrey N. GROSSMAN2


>1Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095?1567, USA

>2U.S. Geological Survey, 954 National Center, Reston, Virginia 20192, USA

>*Corresponding author. E-mail: aerubin at ucla.edu

>(Received 05 May 2009; revision accepted 14 September 2009)



>There are more practical reasons that can be used

>to select the best upper size cutoff for micrometeorites

>and micrometeoroids. Meteorites have long been

>recognized as rare, special kinds of rocks. The practice

>of naming individual meteorites after the places where

>they were found is based on this special status.

>Generally, to receive a name, a meteorite must be well

>classified and large enough to provide material for

>curation and research. Much of the material that

>forms meteorites in the inner solar system is relatively

>coarse grained. Many chondrites and nearly all

>achondrites and iron-rich meteorites have mineral grain

>sizes that exceed 100 lm. Although in many cases it is

>possible to classify small particles of meteoritic

>material at least tentatively, this process is greatly

>hindered when the particle size is significantly smaller

>than the parental rock?s grain size. To allow for

>proper classification, 2 mm is a more useful size cutoff

>than 100 lm. In addition, the number of objects that

>accrete to the Earth (and other bodies) varies

>exponentially with the inverse of mass (e.g., Brown

>1960, 1961; Huss 1990; Bland et al. 1996). Single

>expeditions to recover micrometeorites have found

>thousands of particles in the sub-millimeter size range

>(Rochette et al. 2008), but very few that exceed 2 mm.

>The 2 mm divide also seems to form an approximate

>break between the smallest objects that have

>historically been called meteorites and the largest

>objects called micrometeorites. This leads to additional

>refinements to our definitions:


>Micrometeorites are meteorites smaller than 2 mm in

>diameter; micrometeoroids are meteoroids smaller

>than 2 mm in diameter; objects smaller than 10 lm

>are dust particles.


>By this definition, IDPs are particles smaller than

>10 lm. We are not proposing a lower size limit for IDPs.

>Before it impacted the Earth, object 2008 TC3 was

>approximately 4 m across and was officially classified as

>an asteroid (Jenniskens et al. 2009). It is likely that

>when smaller interplanetary objects are observed

>telescopically, they will also be called asteroids, even if

>they are of sub-meter size. Thus, the boundary between

>meteoroids and asteroids is soft and will only shrink

>with improved observational capabilities. For the

>minimum asteroid size. We thus differ from Beech and

>Steel (1995) who suggested a 10 m cutoff between

>meteoroids and asteroids.


>The Relationship between Meteorites and Meteoroids

>It is tempting to include in our definition of

>meteorite a statement that meteorites originate as

>meteoroids, which, using our modified definition are

>natural solid objects moving in space, with a size less that

>1 m, but larger than 10 lm; this was done in previous

>definitions such as that of McSween (1987). However,

>because the Hoba iron meteorite is larger than 1 m

>across, it represents a fragment of an asteroid, not a

>meteoroid, under our definition of meteoroid. If a mass

>of iron 12 m in diameter deriving from an asteroidal

>core were to be found on Earth or another celestial

>body, it would almost certainly be called a meteorite,

>despite the fact that it was too large to have originated

>as a meteoroid even under the Beech and Steel (1995)

>definition. In addition, the Canyon Diablo iron

>meteorites associated with the Barringer (Meteor)

>Crater in Arizona, are fragments of an impacting

>asteroid that was several tens of meters in diameter

>(e.g., Roddy et al. 1980); the Morokweng chondrite may

>be a fragment of a kilometer-size asteroid that created

>the >70 km Morokweng crater in South Africa (Maier

>et al. 2006).


>Comets, particularly Jupiter-family comets (JFCs),

>could also produce meteorites. A small fraction of JFCs

>evolve into near-Earth objects (Levison and Duncan

>1997) and could impact main-belt asteroids at relatively

>low velocities (approximately 5 km s)1) (Campins and

>Swindle 1998). Meteorites could also be derived from

>moons around planetary bodies. Lunar meteorites are

>well known on Earth, and meteorites derived from

>Phobos may impact Mars, especially after the orbit of

>Phobos decays sufficiently (e.g., Bills et al. 2005).

>We see no simple way out of this semantic

>dilemma, so we add the refinement:


>Meteorites are created by the impacts of meteoroids

>or larger natural bodies.


>Additional Complications

>Fragments of Meteorites


>Meteorite showers result from the fragmentation of

>a meteoroid (or larger body) in the atmosphere. In the

>case of the L6 chondrite Holbrook, about 14,000

>individual stones fell (Grady 2000). Each of these stones

>is considered a meteorite, paired with the others that

>fell at the same time. A meteorite can break apart when

>it collides with the surface of a body or it can fragment

>at a later time due to mechanical and chemical

>weathering. Each fragment of a meteorite is itself

>considered a meteorite, paired with the other objects

>that fell during the same event.


>Degraded Meteorites


>Weathering and other secondary processes on the

>body to which a meteorite accretes can greatly alter

>meteoritic material. Chondritic material has been

>found embedded in terrestrial sedimentary rocks in

>Sweden (e.g., Thorslund and Wickman 1981; Schmitz

>et al. 2001). Other than the minor phase chromite (and

>tiny inclusions within chromite), the primary minerals

>in these extraterrestrial objects have been replaced by

>secondary phases. Despite this extensive alteration,

>some of these rocks (e.g., Brunflo) contain wellpreserved

>chondrule pseudomorphs. Iron meteorites

>can be severely weathered at the Earth?s surface,

>forming a substance known as meteorite shale

>(Leonard 1951) in which the original metal has been

>completely oxidized; nevertheless, this material can still

>preserve remnants of a Widmansta? tten structure. The

>NomCom considers these types of materials to be

>relict meteorites, defined as ??highly altered materials

>that may have a meteoritic origin. . .which are

>dominantly (>95%) composed of secondary minerals

>formed on the body on which the object was found??

>(Meteoritical Society, 2006). Many relict meteorites

>have received formal meteorite names in recent years.

>We support the use of this terminology and would

>further revise our definition as follows:


>An object is a meteorite as long as there is something

>recognizable remaining either of the original minerals

>or the original structure.


>We assert that objects that are completely melted

>during atmospheric transit or weathered to the point

>of complete destruction of all minerals and structures

>should not be called meteorites. This would include

>cosmic spherules (reviewed by Taylor and Brownlee

>1991), ice meteorites that melted, and bits of what

>appear to be separated fusion crust from larger

>meteorites (eight of which have received formal

>meteorite names from the NomCom as relict

>meteorites, incorrectly in our opinion). A report of

>possibly meteoritic material in sediments near the

>Cretaceous ? Tertiary boundary (Kyte 1998) presents a

>borderline case. No primary minerals remain in this

>object although the textures of secondary minerals are

>suggestive of some kind of primary chondritic



>Meteorites accreted by their own parent body

>We now consider whether it is possible for an

>object to become a meteorite on the same celestial

>body from which it was derived. For example, if

>ejecta from a terrestrial impact crater lands back on

>Earth, can it be considered a meteorite? Tektites are

>widely held to be glass objects produced by large

>impacts on Earth. Australite buttons were launched

>on sub-orbital ballistic trajectories from their parent

>crater and quenched into glass; they were partly

>remelted on the way down when they encountered

>denser portions of the atmosphere (e.g., Taylor 1961

>and references therein). Most researchers would likely

>agree that these objects should not be considered

>meteorites. However, if terrestrial ejecta reached the

>Moon, we have argued that it should be considered a

>terrestrial meteorite. The critical difference is that the

>hypothetical material in the latter case escaped the

>dominant gravitational influence of Earth, whereas

>tektites did not.


>Material launched from a celestial body that

>achieves an independent orbit around the Sun or some

>other celestial body, and which eventually is re-accreted

>by the original body, should be considered a meteorite.

>The difficulty, of course, would be in proving that this

>had happened, but a terrestrial rock that had been

>exposed to cosmic rays and had a well-developed fusion

>crust should be considered a possible terrestrial

>meteorite. In a related context, Gladman and Coffey

>(2009) calculated that large fractions of material ejected

>from Mercury by impacts achieve independent orbits

>around the Sun and are re-accreted by Mercury only

>after several million years. Any of this material that

>survived re-accretion could be considered a meteorite.

>The next refinement of the definition of meteorite is



>An object that lands on its own parent body is a

>meteorite if it previously escaped the dominant

>gravitational influence of that body.


>Relative sizes

>As a final clarification, we suggest that:


>An object should be considered a meteorite only if it

>accretes to a body larger than itself.





>From the discussion above, new definitions of

>meteorite and meteoroid are proposed:

>Meteoroid: A 10 lm to 1-meter-size natural solid

>object moving in interplanetary space. Meteoroids may

>be primary objects or derived by the fragmentation of

>larger celestial bodies, not limited to asteroids.

>Micrometeoroid: A meteoroid between 10 lm and

>2 mm in size.

>Meteorite: A natural solid object larger than 10 lm

>in size, derived from a celestial body, that was

>transported by natural means from the body on which

>it formed to a region outside the dominant gravitational

>influence of that body, and that later collided with a

>natural or artificial body larger than itself (even if it is

>the same body from which it was launched). Weathering

>processes do not affect an object?s status as a meteorite

>as long as something recognizable remains of its

>original minerals or structure. An object loses its status

>as a meteorite if it is incorporated into a larger rock

>that becomes a meteorite itself.

>Micrometeorite: A meteorite between 10 lm and

>2 mm in size.


>Interplanetary dust particle (IDP): A particle

>smaller than 10 lm in size moving in interplanetary

>space. If such particles subsequently accrete to larger

>natural or artificial bodies, they are still called IDPs.

>Acknowledgments?We thank our colleagues for useful

>discussions and C. R. Chapman, P. Schweitzer, and

>J. Mars for useful reviews.


>This work was supported in

>part by NASA Cosmochemistry Grants NNG06GF95G

>(A. E. Rubin) and NNH08AI80I (J. N. Grossman).

>Editorial Handling?Dr. A. J. Timothy Jull



>Armstrong J. C., Wells L. E., and Gonzalez G. 2002.

>Rummaging through Earth?s attic for remains of ancient

>life. Icarus 160:183?196.

>Beech M. and Steel D. 1995. On the definition of the term

>?meteoroid?. Quarterly Journal of the Royal Astronomical

>Society 36:281?284.

>Beech M. and Youngblood R. 1994. That which we call a

>meteorite (letter to the editors). The Observatory 114:312.

>Bills B. G., Neumann G. A., Smith D. E., and Zuber M. T.

>2005. Improved estimate of tidal dissipation within Mars

>from MOLA observations of the shadow of Phobos.

>Journal of Geophysical Research 110, E07004, doi: 10.1029/


>Bland P. A., Berry F. J., Smith T. B., Skinner S. J., and

>Pillinger C. T. 1996. The flux of meteorites to the Earth

>and weathering in hot desert ordinary chondrite finds.

>Geochimica et Cosmochimica Acta 60:2053?2059.

>Brown H. 1960. The density and mass distribution of

>meteoritic bodies in the neighborhood of the earth?s orbit.

>Journal of Geophysical Research 65:1679?1683.

>Brown H. 1961. Addendum: the density and mass

>distribution of meteoritic bodies in the neighborhood of

>the earth?s orbit. Journal of Geophysical Research


>Burke J. G. 1986. Cosmic debris: Meteorites in history.

>Berkeley: University of California Press. 445 p.


>Campins H. and Swindle T. D. 1998. Expected characteristics

>of cometary meteorites. Meteoritics & Planetary Science


>Chladni E. F. F. 1794. U? ber den Ursprung der von Pallas

>gefundenen und anderer ihr a?hnlicher Eisenmassen, und u?ber

>einige in Verbindungen stehende Naturerscheinungen. Riga:

>Johann Friedrich Hartknoch.

>Clark L. G. 1984. Long duration exposure facility (LDEF):

>mission 1 experiments in NASA SP-473. Washington, D.C.:

>National Aeronautics and Space Administration.

>Cohen E. 1894. Meteoritenkunde. Stuttgart: Koch. 419 p.

>Connolly H. C. Jr., Zipfel J., Grossman J. N., Folco L., Smith

>C., Jones R. H., Righter K., Zolensky M., Russell S. S.,

>Benedix G. K., Yamaguchi A., and Cohen B. A. 2006.

>The Meteoritical Bulletin, No. 90, 2006 September.

>Meteoritics & Planetary Science 41:1383?1418.

>Craig J. 1849. A new universal etymological, technological and

>pronouncing dictionary of the English language: embracing

>all terms used in art, science, and literature. London: H. G.


>Crawford I. A., Baldwin E. C., Taylor E. A., Bailey J. A., and

>Tsembelis K. 2008. On the survivability and detectability

>of terrestrial meteorites on the Moon. Astrobiology 8:


>Dodd R. T. 1974. Petrology of the St. Mesmin chondrite.

>Contributions to Mineralogy and Petrology 46:129?145.

>Engrand C. and Maurette M. 1998. Carbonaceous

>micrometeorites from Antarctica. Meteoritics & Planetary

>Science 33:565?580.

>Farrington O. C. 1915. Meteorites. Their structure, composition,

>and terrestrial relations. Chicago: O. C. Farrington. 233 p.

>Gladman B. and Coffey J. 2009. Mercurian impact ejecta:

>Meteorites and mantle. Meteoritics & Planetary Science


>Gomes C. B. and Keil K. 1980. Brazilian stone meteorites.

>Albuquerque: University of New Mexico. 161 p.

>Grady M. M. 2000. Catalogue of meteorites; with special reference

>to those represented in the collection of the Natural

>History Museum, London. Edinburgh, UK: Cambridge

>University Press.

>Grossman J. N. 1997. The Meteoritical Bulletin, No. 81, 1997

>July. Meteoritics & Planetary Science 32:159?166.

>Haggerty S. E. 1972. An enstatite chondrite from Hadley Rille

>(abstract). In The Apollo 15 lunar samples, edited by

>Chamberlain J. W. and Watkins C. Houston: Lunar

>Science Institute. pp. 85?87.

>Heinlein R. A. 1966. The Moon is a harsh mistress. New York:

>Putnam. 302 p.

>Huss G. R. 1990. Meteorite infall as a function of mass:

>Implications for the accumulation of meteorites on

>Antarctic ice. Meteoritics 25:41?56.

>Jenniskens P., Shaddad M. H., Numan D., Elsir S., Kudoda

>A. M., Zolensky M. E., Le L., Robinson G. A., Friedrich

>J. M., Rumble D., Steele A., Chesley S. R., Fitzsimmons

>A., Duddy S., Hsieh H. H., Ramsay G., Brown P. G.,

>Edwards W. N., Tagliaferri E., Boslough M. B., Spalding

>R. E., Dantowitz R., Kozubal M., Pravec P., Borovicka J.,

>Charvat Z., Vaubaillon J., Kuiper J., Albers J., Bishop J.

>L., Mancinelli R. L., Sandford S. A., Milam S. N., Nuevo

>M., and Worden S. P. 2009. The impact and recovery of

>asteroid 2008 TC3. Nature 458:485?488.

>Krot A. N., Keil K., Goodrich C. A., Scott E. R. D., and

>Weisberg M. K. 2003. Classification of meteorites. In

>Meteorites, Comets, and Planets, edited by Turekian K. K.


>and Holland H. D. Treatise on geochemistry, Oxford:

>Elsevier. pp. 1?55.

>Kyte F. T. 1998. A meteorite from the Cretaceous ? Tertiary

>boundary. Nature 396:237?239.

>Leonard F. C. 1951. Oxidite or ??meteoritic shale,??

>terrestrialization, and terrestrialite. Popular Astronomy


>Levison H. F. and Duncan M. J. 1997. From the Kuiper Belt

>to Jupiter-family comets: The spatial distribution of

>ecliptic comets. Icarus 127:13?32.

>Love S. G. and Brownlee D. E. 1991. Heating and thermal

>transformation of micrometeoroids entering the Earth?s

>atmosphere. Icarus 89:26?43.

>Maier W. D., Andreoli M. A. G., McDonald I., Higgins M. D.,

>Boyce A. J., Shukolyukov A., Lugmair G. W., Ashwal L.

>D., Graeser P., Ripley E. M., and Hart R. J. 2006.

>Discovery of a 25-cm asteroid clast in the giant Morokweng

>impact crater, South Africa. Nature 441:203?206.

>Mason B. 1962. Meteorites. New York: Wiley. 274 p.

>McSween H. Y. 1976. A new type of chondritic meteorite

>found in lunar soil. Earth and Planetary Science Letters


>McSween H. Y. 1987. Meteorites and their parent planets.

>Cambridge: Cambridge University, 237 p.

>Meteoritical Society. 2006. Guidelines for meteorite

>nomenclature, revised October 2006. http://www.


>Millman P. M. 1961. Meteor news. Journal of the Royal

>Astronomical Society of Canada 55:265?267.

>Nininger H. H. 1933. Our stone-pelted planet. Boston: Houghton

>Mifflin. 237 p.

>Rochette P., Folco L., Suavet C., van Ginneken M.,

>Gattacceca J., Perchiazzi N., Braucher R., and Harvey R.

>P. 2008. Micrometeorites from the Transantarctic

>Mountains. Proceedings of the National Academy of

>Science 105:18,206?18,211.

>Roddy D. J., Schuster S. H., Kreyenhagen K. N., and Orphal

>D. L. 1980. Computer code simulations of the formation

>of Meteor Crater, Arizona: Calculations MC-! and MC-2.

>Proceedings, 11th Lunar and Planetary Science

>Conference. pp. 2275?2308.

>Rubin A. E. 1997. The Hadley Rille enstatite chondrite and its

>agglutinate-like rim: Impact melting during accretion to

>the Moon. Meteoritics & Planetary Science 32:135?141.

>Rubin A. E., Scott E. R. D., Taylor G. J., Keil K., Allen J. S.

>B., Mayeda T. K., Clayton R. N., and Bogard D. D. 1983.

>Nature of the H chondrite parent body regolith: evidence

>from the Dimmitt breccia. Proceedings, 13th Lunar and

>Planetary Science Conference. pp. A741?A754.

>Schmitz B., Tassinari M., and Peucker-Ehrenbrink B. 2001. A

>rain of ordinary chondritic meteorites in the early

>Ordovician. Earth and Planetary Science Letters 194:


>Schro? der C., Rodionov D. S., McCoy T. J., Jolliff B. L., Gellert

>R., Nittler L. R., Farrand W. H., Johnson J. R., Ruff S. W.,

>Ashley J. W., Mittlefehldt D. W., Herkenhoff K. E.,

>Fleischer I., Haldemann A. F. C., Klingelho? fer G., Ming D.

>W., Morris R. V., de Souza P. A. Jr., Squyres S. W., Weitz

>C., Yen A. S., Zipfel J., and Economou T. 2008. Meteorites

>on Mars observed with the Mars Exploration Rovers.

>Journal of Geophysical Research 113:E06S22.

>Scott E. R. D., Lusby D., and Keil K. 1985. Ubiquitous

>brecciation after metamorphism in equilibrated ordinary

>chondrites. Proceedings, 16th Lunar and Planetary Science


>Conference. Journal of Geophysical Research 90:


>Shapiro I. I. 1963. New method for investigating

>micrometeoroid fluxes. Journal of Geophysical Research


>Taylor S. R. 1961. Distillation of alkali elements during

>formation of australite flanges. Nature 189:630?633.

>Taylor S. and Brownlee D. E. 1991. Cosmic spherules in the

>geologic record. Meteoritics 26:203?211.

>Thorslund P. and Wickman F. E. 1981. Middle Ordovician

>chondrite in fossiliferous limestone from Brunflo, central


>Wells H. G. 1898. The war of the worlds. London: William

>Heinemann. 303 p.

>Yanai K., and Kojima H. 1995. Catalog of the Antarctic

>meteorites. Tokyo: Nat. Inst. Polar Research, Tokyo. 230 p.

>Zolensky M., and Ivanov A. 2003. The Kaidun microbreccia

>meteorite: A harvest from the inner and outer asteroid

>belt. Chemie der Erde 63:185?246.

>Zolensky M. E., Weisberg M. K., Buchanan P. C., and

>Mittlefehldt D. W. 1996. Mineralogy of carbonaceous

>chondrite clasts in HED achondrites and the Moon.

>Meteoritics & Planetary Science 31:518?537.


>Shawn Alan


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