|
||||||||
|
Official names used by the Meteoritical SocietyPairings : guidelines used for desert meteorites |
| A new meteorite shall be named after a nearby geographical locality, such as a town, village, river, bay, cape, mountain or island which appears on widely used maps and is sufficiently close to the recovery site to convey meaningful locality information. In sparsely populated areas with few place names, like Sahara desert, meteorites fall into two categories: 1 - Meteorites from well known Saharan strewnfields and sparse place names. 2 - Meteorites of unknown or poorly known provenance. |
|
1
Meteorites from well known Saharan strewnfields and sparse place names.
The following rules apply to cases involving insufficient numbers of unique place-names. That's the case with dense collection areas like Saharan strewnfields. These are meteorites collected directly on the strewnfields, with exact GPS localization and complete documentation. Two well known Libyan strewnfields are the plateau of Dar al Gani and the vast area of Hammada al Hamra. Meteorites from these places take the name of the place followed by a number, 001 for the first one classified, 002 the second... |
|
The plateau of Dar al Gani in Libya, measure 120 km x 60 km. With a thousand itemized meteorites plus its significant potential for meteorites smaller than 100 grams, the plateau of Dar al Gani rivals the whole continent of Antarctica which has produced 2000 meteorites. Unlike the majority of the finds in Antarctica, the Dar al Gani meteorite finds also yield information enabling one to plot their respective ellipse fields!
|
+ Daraj: 146 meteorites, numbers 001 to 146 Daraj (or Derdj) is named for the last town prior to entering the desert plateau. The Daraj meteorites are found on the west part of the Hammada al Hamra plateau. The Hammada al Hamra (the red plateau) extends up to 300 km east of the town of Daraj, and has been routinely prospected since 1986. With the discovery of over 450 meteorites, Hammada al Hamra remains, after Dar al Gani, one of the top meteorite prospecting sites in the Sahara, along with Acfer in Algeria.
The distribution of meteorites currently stands at one for every 200 sq km for the entire western region. However, the most favorable prospecting zone, which is very clear and subject to erosion, is situated to the south-east, and shows a distribution close to one for every 20 sq km.
|
+ Aguemour: 17 meteorites, numbers 001 to 017
|
|
|
Also little spots not as prospected as the major strewnfields
Beware of Moroccan names which were approved prior to the decision by the Nomenclature Committee to create the NWA series, like Agoult, Aoufous, Igdi, Smara, El Gouanem, Ouzina... and all the commercial names that you will never find in official publications.
|
|
2
Meteorites of unknown or poorly known provenance.
In cases where many meteorites are found and distributed or sold without careful documentation of provenance, a numbered sequence of generic names should be used, wherein the prefix reflects the geographic area in which the meteorites were most likely recovered (e.g., Northwest Africa, for meteorites coming from marketplaces in Morocco). These are provisional names allowed by the Nomenclature Committee. When a collector or dealer brings back a possible meteorite from Morocco, he or she can apply for an NWA number to be assigned. Only, when such a meteorite is classified by an authorized laboratory and a type specimen is deposited for scientific research in a permanent collection, it could then be granted formal (official) status by a Nomenclature Committee vote. But until this happens, there is no guarantee that it is even a meteorite. It is the door wide open to all sorts of frauds. You can tell that a name is a formal one because the meteorite has been published in the Meteoritical Bulletin, either in MAPS (Meteoritics and Planetary Science) or on-line in the latest MetBull update. If their name doesn't appear in the Meteoritical Bulletin, it's not an official name, so be careful. We invite every collector to have a look at the Meteoritical Bulletin Master index or at the Natural History Museum's meteorite catalogue database: SEE BELOW! |
You will never see photos in situ for these meteorites without documentation. They are bought in Morocco, the majority of them comes from either Algeria, Libya, Mauritania or anywhere within the Africa continent! The locality information associated with these meteorites is lost. All such meteorites are henceforth numbered in a "Northwest Africa" (NWA) series.
Many NWA numbers will never get an official classification.
NWA xxxx, are associated with the plundering of Saharan strewnfields and the loss of paired specimens.
|
These meteorites have been collected by Marc, Luc and Jim Labenne in the Sahara and anonymous finders. The Labennes will not disclose the exact locations of these meteorites at the present time. - Meteoritical Bulletin N°83, only 23 are classified Many Sahara xxxxx are just provisional names. See definition above.
|
Pairings : guidelines used for desert meteorites
PAIRED AND SEPARATED METEORITES "A reasonable effort should be made to ensure that a new recovery does not belong to a previously named meteorite. If two meteorites previously thought to be separate are subsequently found to be paired after comprehensive studies (preferably of the main masses), one name should be abolished and one retained." In areas of dense meteorite concentrations such as desert strewnfields, where ellipses of fall are overlapping and classification are done by different laboratories, it may not be practical to apply the guidelines above. In such cases, the following guidelines apply:
If two or more numbered meteorites are subsequently determined to be paired, their names should not be changed. Such pairing groups may be referred to collectively by the lowest specimen number, the most widely studied mass number or the largest mass number (e.g., the DaG 749 pairing group). This working method avoids confusion and the desert meteorite maintains the initial name as well as the numeric suffix given to it by the Meteoritical Committee. As far as possible, we update our reference cards with new pairing information as well as with data lists and strewnfield maps. Dar al Gani CO3 probable paired specimens : DaG 005, 006, 023, 025, 027, 032, 067, 078, 081, 082, 083, 136, 137, 171, 173, 186, 188, 189, 190, 191, 192, 194, 203, 204, 226, 227, 228, 229, 230, 231, 289, 291, 331, 332, 601, 667, 668, 749, 845, 846, 847, 848, 852, 853, 854, 858, 998... (NWA 062?)
The complete guidelines for meteorite nomenclature is available here:
|
The METEORITICAL SOCIETYThe Society is a non-profit organization founded in 1933 with the help of Harvey H. Nininger. It was formed to promote the study of meteorites and other samples of extraterrestrial matter and their relation to the origin and history of the solar system. There are currently around 950 members representing some 33 countries. The Society attracts both professional scientists from a variety of backgrounds (geology, chemistry, physics, astronomy) as well as amateurs interested in meteorites and impact craters. Areas of interest include asteroids, comets, craters, interplanetary dust, interstellar medium, lunar samples, meteors, meteorites, natural satellites, planets, tektites, and the origin and history of the solar system. The Meteoritical Society is the official organization that maintains an inventory of all new meteorite discoveries, meteorite falls and any works about meteorites published anywhere in the world. The society publishes the journal Meteoritics and Planetary Science (MAPS). The supplemental METEORITICAL BULLETIN, which contains all newly classified meteorites, is published annually. This document is the only reliable source of information for the entire community and any serious collector.
A listing of all the meteorites published from 1957 to 2002: "People buying/trading meteorites should also keep in mind that if a meteorite name (including its number, if any) does NOT appear in the Met. Bulletin (published or on-line), then there is no guarantee that it has ever been looked at by a meteorite expert or that the NomCom has ever scrutinized the name, location data, classification, etc. (or worse, it HAS scrutinized the information and rejected/changed it!)". A complete database with search engine on the Natural History Museum's website: |
|
 |
