Glossary of meteoritics

This is a glossary of terms used in meteoritics, the science of meteorites.

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2 Pallas – an asteroid from the asteroid belt and one of the likely parent bodies of the CR meteorites.
4 Vesta – second-largest asteroid in the asteroid belt and likely source of the HED meteorites.
221 Eos – an asteroid from the asteroid belt and one of the likely parent bodies of the CO meteorites.
289 Nenetta – an asteroid from the asteroid belt and one of the likely parent bodies of the angrites.
3103 Eger – an asteroid from the asteroid belt and one of the likely parent bodies of the aubrites.
3819 Robinson – an asteroid from the asteroid belt and one of the likely parent bodies of the angrites.
IA meteorite – an iron meteorite group now part of the IAB group/complex.
IAB meteorite – an iron meteorite and primitive achondrite of the IAB group/complex.
IB meteorite – an iron meteorite group now part of the IAB group/complex.
IC meteorite – an iron meteorite that is part of the IC group.

A

Ablation – the process of a meteorite losing mass during the passage through the atmosphere.
Acapulcoite – a group of primitive achondrites.
Accretion – the process in which matter of the protoplanetary disk coalesces to form planetesimals.
Achondrite – a differentiated meteorite (meaning without chondrules).
Aerolite – an old term for stony meteorites.
ALH – an abbreviation used for meteorites from Allan Hills.
Allan Hills 84001 – is an exotic meteorite from Mars that does not fit into any of the SNC groups and was thought to contain evidence for life on Mars.
Allende meteorite – is the largest carbonaceous chondrite ever found on Earth.
Amphoterite – an obsolete classification of chondritic meteorites that are now classified as LL.
Angrite – a basaltic meteorite.
ANSMET – the Antarctic Search for Meteorites is a scientific program that looks for meteorites in the Transantarctic Mountains.
Asteroidal achondrite – an achondrite that differentiated on an asteroid or planetesimal (see planetary achondrite)
Asteroid spectral types – classification of asteroids according to their spectra.
Ataxite – an iron meteorite that has no visible structures when etched.
Aubrite – a class of achondrite meteorites composed primarily of the orthopyroxene enstatite

B

Basaltic achondrite – a grouping of basalt meteorites (HED meteorites + Angrite)
Brachinite – either a primitive achondrite or an asteroidal achondrite
Bolide – is an extremely bright meteor, especially one that explodes in the atmosphere

C

C – can refer to carbonaceous chondrite or to an iron meteorite designation (Roman numeral and letter).
Carbonaceous chondrite
CAI – an abbreviation of calcium–aluminium-rich inclusion
Calcium–aluminium-rich inclusion
Chassignite
Chondrite – stony meteorites unmodified by melting or differentiation of the parent body
Chondrule – millimetre-scale round grains found in chondrites
Clan – meteorites that are not similar enough to form a group, but are also not too different from each other to be put in separate classes.^[1]
Class – two or more groups that have a similar chemistry and oxygen isotope ratios.^[1]
Compositional type – a classification based on overall composition, for example stony, iron, stony-iron (as introduced by Maskelyne). Can also refer to the composition deduced from spectroscopy of asteroids.
Condensation – the process of chemicals changing from the gaseous to the solid phase during the cooling of the protoplanetary disk.
Condensation sequence – the sequence of minerals that changes from the gaseous to the solid state while the protoplanetary disk cools.
Cosmic dust – small interplanetary and interstellar particles that are similar to meteorites (See Micrometeorite).
Cosmochemistry – the study of the chemical composition of the universe and its constituents, and the processes that produced those compositions.^[2]

D

Dar al Gani – a meteorite field in the Libyan Sahara.
Desert glass – natural glass found in deserts formed from the silica in sand as a result of lightning strikes or meteor impacts.
Differentiated – a meteorite that has undergone igneous differentiation. (See: achondrite)
Differentiation – usually the process of a planetesimal forming an iron core and silicate mantle.
Duo – a grouping of two meteorites that share similar characteristics (see Grouplet).

E

E – can refer to enstatite chondrite or to an iron meteorite designation (Roman numeral and letter).
Eagle Station grouplet – a set of pallasite meteorite specimen that do not fit into any of the defined pallasite groups.
Electrophonic bolide – a meteoroid which produces a measurable discharge of electromagnetic energy (EMP) during its passage through the atmosphere.
Enstatite achondrite – a meteorite that is mostly composed of enstatite. Usually part of the aubrite group.
Enstatite chondrite – a rare form of meteorite thought to comprise only 2% of chondrites.

F

Fall – a meteorite that was seen while it fell to Earth and found.
Find – a meteorite that was found without seeing it fall.
Fossil meteorite – a meteorite that was buried under layers of sediment before the start of the Quaternary period. Some or all of the original cosmic material has been replaced by diagenetic minerals.^[3]^: 320 (It is, however, not a fossil).
Fusion crust – a coating on meteorites that forms during their passage through the atmosphere.

G

Group – a collection of five or more meteorites sharing similar characteristics.^[1]
Grouplet – a collection of fewer than five meteorites sharing similar characteristics.^[1]

H

Hammer Stone – a specific individual meteorite that has hit either a human, man-made object, and/or an animal.
HED – abbreviation for three basaltic achondrite groups howardite, eucrite and diogenite.
HED meteorite – a clan of basaltic achondrites.
Hexahedrite – a structural class of iron meteorites having a relatively low nickel content
Hunter – a person who searches for meteorites.

I

Impact breccia – rock composed of fragments of terrestrial, extraterrestrial or mixed origin fused by the energy of impact
Impactite – informal term for a terrestrial rock resulting from the shocking impact of a meteor.
Iron–nickel alloy – an alternative expression for meteoric iron.
Iron meteorite – a meteorite that is mainly composed of meteoric iron.

K

Kakangari chondrite – a group of chondrite meteorites.
Kamacite – a native metal (mineral) found in meteorites.

L

Lodranite – member of a small group of primitive achondrites thought to derive from deeper within the same parent body as acapulcoites
Lunaite – a meteorite that originated from the Moon (synonym of Lunar meteorite). Compare Category:Meteorites found on bodies other than Earth.
Lunar meteorite – a meteorite that originated from the Moon (synonym of Lunaite). Compare Category:Meteorites found on bodies other than Earth.

M

Main group pallasite – a pallasite belonging to the main group.
Main mass – the largest/heaviest piece of a fragmented meteorite, typically found in a strewn field.
Magmatic meteorite
Martian meteorite – a meteorite that originated from Mars. Compare Category:Meteorites found on bodies other than Earth.
Maskelynite – a natural glass found in meteorites.
Matrix – the mineral assemblage surrounding chondrules.
Mesosiderite – a grouping of stony-iron meteorite that are breccias.
Meteoric iron – a native metal found in meteorites and a mixture of different mineral phases. Compare telluric iron.
Meteorite Observation and Recovery Program – a scientific program that was centered in Canada.
Meteoriticist – a scientist working on meteorites, meteors, and meteoroids.
Meteoritics – the science of meteorites, meteors, and meteoroids.
MORP – abbreviation for Meteorite Observation and Recovery Program.
Micrometeorite – microscopic meteorites derived from Cosmic dust.

N

Nakhlite – a group of Martian meteorites
Neumann lines (or Neumann bands) – a pattern of fine parallel lines seen in some iron meteorites, thought to be due to impact events on the parent body
Nonmagmatic meteorite – (deprecated) iron meteorites that were thought to have not formed by igneous processes.

O

O – usually refers to ordinary chondrite
Observed fall – a meteorite that was seen when it fell to Earth.
Octahedrite – the most common structural class of iron meteorites.
Ordinary chondrite – a chondrite meteorite, where 'ordinary' means that it is the most common found

P

PAC – abbreviation for primitive achondrite.
Pallasite – a class of stony–iron meteorite.
Panspermia – the hypothesis that life could reach other planets by the means of meteorites and/or comets.
Parent body – the celestial body from which originates a meteorite or a class of meteorites.
Petrologic type – a classification scheme that expresses the degree to which a meteorite has been affected by the secondary processes of thermal metamorphism and aqueous alteration on the parent asteroid.
Pitts grouplet – a grouplet of meteorites that is part of the IAB meteorites.
Planetary achondrite – an achondrite that was differentiated on a planet and not a planetesimal or asteroid (See asteroidal achondrite).^[4]
Plessite – a fine grained intergrowth found in meteoric iron consisting of kamacite, taenite and tetrataenite lamella.^[5]
Presolar grains – interstellar solid matter in the form of tiny solid grains from a time before the Sun was formed.
Primitive meteorite
Primitive achondrite – a meteorite that has similarities to achondrites and chondrites.
Protoplanetary disk – a circumstellar disk from which all solids in the Solar System formed.
Pyroxene pallasite grouplet

R

Regmaglypts – thumbprint-sized indentations in the surface of larger meteorites formed by ablation as the meteorite passes through a planet's atmosphere, probably caused by vortices of hot gas.^[6]
Rose-Tschermak-Brezina classification – a classification developed by Gustav Rose, Gustav Tschermak and Aristides Brezina.
Rumuruti chondrite – a group of chondrites.

S

Shergottite – igneous rocks of mafic to ultramafic lithology, named after a meteorite that fell at Sherghati, India in 1865.
Shock stage – a measure of the degree of fracturing of the matrix of a common chondrite meteorite.
Shock metamorphism – the effects of shock-wave related deformation and heating during impact events.
Siderite – the old term for iron meteorite.
Siderolite – the old term for stony-iron meteorites.
SNC – abbreviation for shergottite, nakhlite and chassignite, the three main types of Martian meteorite.
Solar nebula – a synonym of the protoplanetary disk.
Spectral class –
Stony meteorite – a meteorite composed mostly of silicates.
Stony-iron meteorite – a meteorite that is a mixture of meteoric iron and silicates.
Strewn field – a field of fragments from one meteorite fall.
Structural class – a subdivision of iron meteorites in ataxites, hexahedrites and octahedrites.
Superbolide – is a bolide that reaches an apparent magnitude of −17 or brighter, which is roughly 100 times brighter than the full moon. Recent examples of superbolides include the Sutter's Mill meteorite and the Chelyabinsk meteor.

T

Taenite – a native metal (mineral) found in meteorites.
Tamdakht – a meteorite that fell near Ouarzazate, Morocco on 2008-12-20 producing a strewn field of approximately 25 km (16 mi) by 2 km (1.2 mi) and two small impact craters.
Tektite – glassy terrestrial debris created by meteorite impacts.
Thumbprinting – see regmaglypts
Total known weight (TKW) – total known mass of a meteorite.
Trio – a grouping of three meteorites that share similar characteristics (see Grouplet).
Type – subdivision of meteorites. Loosely defined. Usually refers to chondrite, achondrite and sometimes primitive achondrite.^[1]

U

Udei Station grouplet – a grouplet of meteorites that is part of the IAB meteorites.
Ungrouped – a meteorite that has not been assigned to a group or grouplet.
Undifferentiated
Ureilite

V

Vesta – second largest asteroid in the asteroid belt and likely source of the HED meteorites.
Volatile elements – are chemical elements that have low boiling and condensation temperatures.

W

Widmanstätten pattern – a fine interleaving of kamacite and taenite bands/ribbons found in octahedrite irons and some pallasites.
Willamette meteorite – the largest meteorite discovered in North America, found in the Willamette Valley of Oregon.
Winonaite – a type of primitive achondrite meteorite.
Weston meteorite – a meteorite which fell to earth above the town of Weston, Connecticut on December 14, 1807.^[7]

References

^ a b c d e M. K. Weisberg; T. J. McCoy, A. N. Krot (2006). "Systematics and Evaluation of Meteorite Classification" (PDF). In D. S. Lauretta; H. Y. McSween, Jr. (eds.). Meteorites and the early solar system II. Tucson: University of Arizona Press. pp. 19–52, 942. ISBN 978-0816525621. Retrieved 15 December 2012.
^ McSween, Harry Y. (2021). Cosmochemistry. Gary R. Huss. Cambridge, United Kingdom. ISBN 978-1-108-88526-3. OCLC 1259294621.{{cite book}}: CS1 maint: location missing publisher (link)
^ Schmitz, B.; Tassinari, M. (2001), "Fossil Meteorites", in Peucker-Ehrenbrink, B.; Schmitz, B. (eds.), Accretion of Extraterrestrial Matter Throughout Earth's History, New York: Springer, pp. 319–31, doi:10.1007/978-1-4419-8694-8_17, ISBN 978-1-4613-4668-5
^ Agee, C. B.; N.V. Wilson; F.M. McCubbin; Z.D. Sharp; K. Ziegler (2012). "Basaltic Breccia NWA 7034: New ungrouped planetary Achondrite" (PDF). 43rd Lunar and Planetary Science Conference (1659): 2690. Bibcode:2012LPI....43.2690A. Retrieved 4 January 2013.
^ Goldstein, J. I.; Michael, J. R. (1 April 2006). "The formation of plessite in meteoritic metal". Meteoritics & Planetary Science. 41 (4): 553–70. Bibcode:2006M&PS...41..553G. doi:10.1111/j.1945-5100.2006.tb00482.x.
^ "regmaglypts". Meteorite or Meteorwrong?. Department of Earth and Planetary Sciences, Washington University in St. Louis. Archived from the original on 6 March 2016. Retrieved 15 January 2013.
^ "The Weston Meteorite (Yale Peabody Museum)". 7 December 2010.