Breadcrumbs
The Martian Meteorite Compendium
Acronyms and Terms
(also see Dictionary of Geological Terms)
- Achondrite
- Stony meteorite, lacking chondrules. Igneous origin. Relatively rare.
- ANSMET
- Antarctic Search for Meteorites, funded by U. S. National Science Foundation; led by William Cassidy and Ralph Harvey.
- AMN
- Antarctic Meteorite Newsletter (issued by NASA-JSC, Astromaterials Curation Office).
- ARES
- Astromaterials Research and Exploration Science at the Johnson Space Center.
- "Blue Ice"
- Locations in Antarctica where samples were recovered (Map of Antarctic Meteorite Locations).
- ALH
- Allan Hills Icefield.
- EET
- Elephant Moraine.
- LAR
- Larkman Nunatak.
- LEW
- Lewis Cliffs Ice Field.
- MIL
- Miller Range.
- QUE
- Queen Alexander Range.
- RBT
- Roberts Massif.
- YAMATO
- Yamato Mountains.
- GRV
- Grove Mountains.
- BM (now NHM)
- British Museum of Natural History, now The Natural History Museum, London.
- Chassignite
- Type of meteorite like Chassigny, which is an olivine-rich dunite, thought to be from Mars.
- Cosmogenic Isotopes
- Isotopes produced by interaction of high-energy cosmic rays with elements in sample.
- DaG
- Dar al Gani, Libya.
- Deflation
- Wind erosion area.
- Dho
- Dhofar, Oman.
- Diabasic
- Mafic subvolcanic rock type that is compositionally equivalent to basalt, and typically contains plagioclase feldspar, pyroxene, and olivine as the major minerals; also a class of the shergottite meteorites.
- DML
- Dark mottled lithology of Zagami meteorite.
- DN
- Olivine-rich lithology of Zagami, obtained from David New.
- Druse
- A crust or coating of small crystals in a crack or void (see Martinez and Gooding, 1986 for a description of "white-druse").
- dpm
- Disintegrations per minute.
- Educational Thin Section Set
- JSC, BM(NHM) and NIPR all have sets of thin sections of meteorites, with educational pamphlets, for use by educational institutions.
- EMPA
- Electron microprobe analysis.
- Ejection age
- The sum of the exposure age and terrestrial age, the time since the sample was ejected from Mars.
- Exposure age
- The time interval a small body (~1m) spends in space as measured by radionuclides generated by high energy cosmic rays.
- Fusion crust
- Thin glass coating found on outer surface of meteorite due to heating by atmospheric entry.
- Gabbroic
- Coarse-grained mafic intrusive rocks, compositionally equivalent to basalt, and consisting of olivine, pyroxene, and plagioclase feldspar as the major minerals; also a class of the shergottite meteorites.
- HED
- Howardite, Eucrite, Diogenite. Large group of apparently related achondrites.
- g
- gram (also kg = kilogram and mg = milligram etc.).
- Ga
- 1,000,000,000 years.
- GPa
- Giga Pascals (unit of pressure).
- IDMS
- Isotope Dilution Mass Spectroscopy.
- INAA
- Instrumental Neutron Activation Analysis.
- Isochron
- A constant-time line on a diagram that compares ratios of radioactive isotopes to their stable daughter isotopes.
- Interstitial
- Area between the other major mineral phases.
- JaH
- Jiddat al Harasis, a dense meteorite collection area in Oman.
- JSC
- Lyndon B. Johnson Space Center, Houston, Texas 77058
- Katabatic wind
- The wind that blows off of the Antarctic continent.
- lherzolite
- Two pyroxene rock, plutonic.
- Lithology A, B, and C
- Three distinct lithologies in the meteorite EET 79001; lithology A is olivine-phyric, lithology B is diabasic, and lithology C is glassy melt pocket thought to have formed by impact on Mars.
- Ma
- 1,000,000 years
- Martian Meteorite
- A meteorite from Mars; also previously called "SNC" meteorites — Shergottites–Nakhlites–Chassigny.
- MER
- Mars Exploration Rovers – Spirit and Opportunity.
- MWG
- Meteorite Working Group. U. S. advisory panel to ANSMET/NASA/Smithsonian.
- Magmatic inclusion
- Small recrystallized glass inclusions usually found in early-formed olivine or chromite crystals (presumably trapped magmatic liquid).
- Maskelynitization
- Shock event that converts plagioclase into isotropic glass phase called maskelynite.
- Mesostasis
- Fine-grained mineral mass found interstitial to major minerals.
- Mineralogical mode
- The mineral percentages, usually expressed as volume percent.
- "mineral" separate
- An attempt to obtain a concentration of one mineral phase after powdering the rock and using various mechanical means (e.g. heavy liquids for density difference).
- Nakhlites
- Clinopyroxenites like Nakhla, Lafayette, Governador Valadares, NWA 817, Y000593.
- NHM
- The Natural History Museum, London.
- NIPR
- National Institute Polar Research, Japan
- NWA
- North West Africa. Meteorites usually purchased from nomads in Morocco, but probably found in Algeria or even further east in Sahara.
- NZ
- Normal, basaltic lithology of Zagami.
- Olivine-phyric
- Texture of mafic or ultramafic rock where large olivine phenocrysts occur in a finer-grained matrix or groundmass; also a class of the shergottite meteorites.
- Ophitic
- Texture of basaltic rock where pyroxene completely encloses plagioclase and other phases.
- "orangette"
- New term used to distinguish unusual carbonate globules in ALH84001. However, term never caught on.
- PAHs
- Polycyclic aromatic hydrocarbons. Organic compounds made up of benzene rings linked together.
- Pathfinder
- Highly successful mission to Martian surface in 1990s.
- Pre-terrestrial
- The history of the sample before entry into the Earth's atmosphere – as judged by location with respect to fusion crust.
- Plateau age
- The age obtained from the 39Ar/40Ar spectrum as function of release temperature.
- "pockets" of glass
- The small areas of glass found inside the meteorite specimen.
- "pods" of glass
- The small unusual glass areas in EETA79001. See figure IX–24.
- Poikilitic
- Texture of igneous rock where small granular crystals are irregularly scattered without common orientation in a larger crystal of another mineral; also a class of the shergottite meteorites.
- ppm
- parts per million or micrograms per gram (unit of concentration) (1 in 1,000,000).
- ppb
- parts per billion or nanograms per gram (1 in 1,000,000,000).
- Radiogenic Isotopes
- Naturally-occurring, radioactive isotopes such as K, Rb, U, Th, Sm that decay at a slow rate to another stable isotope and are used for geological age dating.
- REE
- Rare earth elements (actually not so rare, generally diagnostic).
- RNAA
- Radiochemical neutron activation analysis (generally superior to INAA, because of use of internal standard).
- "rosette"
- A symmetrical growth form, resembling a rose, assumed by an accretionary body. Term often used for barite concretions on Earth.
- SaU
- Sayh al Uhaymir, Oman.
- "salts"
- Various non-silicate minerals, possibly residual to aqueous solution, found in cracks of Martian meteorites.
- SEM
- Scanning electron microscope
- Schlieren
- Texture where glass, or mineral phases are drawn out in stringers.
- SIMS
- Secondary Ion Mass Spectroscopy.
- SNC
- Shergotty, Nakhla, Chassigny, a term used in publications before "Martian meteorites."
- Smithsonian Institution
- see USNM below
- SPB
- Shergottite Parent Body = Mars
- ST (replaced by KT,
and then replaced now by XI2) - The mail code for the "Office of the Curator" at JSC.
- Shergottites
- Meteorite type that includes several different kinds of rocks – a) those traditionally referred to as basaltic but now subdivided into diabasic, fine-grained, and gabbroic; b) those traditionally referred to as lherzolitic and now poikilitic, and c) olivine-phyric.
- TEM
- Transmitted electron microscope.
- Terrestrial age
- Time interval that meteorite has spent on Earth (for example, can sometimes be determined by analysis of carbon 14).
- USNM
- United States National Museum, also called the Smithsonian Institution. Washington D.C. Specifically, the Department of Mineral Sciences is a great source of research samples.
- Viking
- Two highly-successful missions to the surface of Mars in 1976.
- "whole-rock"
- Term used for a small sample (50 mg–2 g) of a rock used to determine the chemical composition of the "whole" specimen. Generally selected to be representative of the "whole", but, obviously, NOT the whole rock.
- XRF
- X-ray flouresence
- "Yowza-Yowza"
- Term used by 1984 ANSMET team to describe something important. New geological term, not found in Dictionary.