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Chergach
Basic information Name: Chergach
     This is an OFFICIAL meteorite name.
Abbreviation: There is no official abbreviation for this meteorite.
Observed fall: Yes
Year fell: 2007
Country: Mali
Mass:help 100 kg
Classification
  history:
Meteoritical Bulletin:  MB 94  (2008)  H5
Recommended:  H5    [explanation]

This is 1 of 7781 approved meteorites (plus 11 unapproved names) classified as H5.   [show all]
Search for other: H chondrites (type 4-7), Ordinary chondrites (type 4-7), H chondrites, and Ordinary chondrites
Comments: Approved 4 May 2008
Writeuphelp
Writeup from MB 94:

Chergach                   23° 4147’’N, 5° 0053W

SW El Mokhtar, Erg Chech, Timbuktu district, Mali

Fall: 2 or 3 July 2007, daytime

Ordinary chondrite (H5)

History: In fall and winter, 2007 ~100 kg of meteorites were collected in the Erg Chech, north of Taoudenni. Nomads reported the stones fell after a smoke cloud was seen and several detonations were heard over a wide area during daytime in July 2007. The finder of the first meteorites was Mr Ouled Bleila, who died in a car accident on his way back from the trip to the Chergach strewn field in October 2007. According to the Tuareg people from Algeria who visited the fall site in September 2007, the elliptical strewn field stretches for more than 20 km in a northeasterly direction. No fireball was reported.

Physical characteristics: A large number of fusion-crusted stones have been recovered, the largest ones are 17.8 and 13.9 kg, the smallest ones about 1.5 g. Total known weight ~100 kg.

Petrography: (E. Gnos, MHNGE; B. Hofmann, NMBE, M. Eggimann, UBE/NMBE) Mean chondrule size is 0.38 mm (n = 61). Mean size of plagioclase grains is ~20 μm. Troilite is polycrystalline, rich in silicate inclusions, and shows diffuse boundaries to metal. Some metal is rich in silicate- and troilite inclusions. No Cu metal observed. Shock stage is S3, some shock veins are visible, no weathering (W0). In addition to this dominant lithology, a significant number of stones consist of chondritic clasts (H5 S3-4 W0, identical to the homogeneous lithology) set in a fine-grained, black, silicate impact melt matrix with abundant droplets of metal and metal-troilite. Shock stage of small clasts is up to S4.

Mineral compositions and geochemistry: Olivine Fa18.2 (chondrite fragments in impact melt are Fa18.4), pyroxene Fs15.5 Wo1.2 (fragments in impact melt are Fs16.0, Wo1.4).

Cosmogenic radionuclides: (Patrick Weber, Particle Physics Group, Institute of Physics, University of Neuchâtel) Gamma-spectroscopy performed in November, 2007 showed the presence of the following short-lived radionuclides: 46Sc, 56Co, 54Mn, 58Co, 7Be, 57Co, 22Na, 60Co, 26Al. Recalculated to July, 2007, 22Na was 44.0 ± 1.1 dpm/kg and 26Al 20.8 ± 0.8 dpm/kg. The 22Na/26Al activity ratio of 2.1 is consistent with a fall in July, 2007 and demonstrates that this material is not identical with Bassikounou.

Classification: Ordinary chondrite (H5), some stones suggest an H impact melt breccia. S3, W0.

Type specimens and distribution: 115 g at NMBE; 17.8 kg P. Hermann, Canada; 13.9 kg D. Gheesling, USA; 4.9 kg S. Buhl, Germany.

 

Data from:
  MB94
  Table 1
  Line 3:
State/Prov/County:Timbouctou district, Mali
Date:2-Jul-07
Latitude:23°41'47"N
Longitude:5°00'53'W
Mass (g):100000
Pieces:Many
Class:H5
Shock stage:S3
Weathering grade:W0
Fayalite (mol%):18.2
Ferrosilite (mol%):15.5
Wollastonite (mol%):1.4
Classifier:
Type spec mass (g):115
Type spec location:NMBE, E. Gnos, MHNGE; B. Hofmann, NMBE, M. Eggimann, UBE/NMBE
Main mass:Dgheesling
Institutions
   and collections
NMBE: Natural History Museum Bern Bernastrasse 15 CH-3005 Bern Switzerland, Switzerland; Website (institutional address; updated 2 Mar 2012)
MHNGE: Muséum d’histoire naturelle, Route de Malagnou 1, CH-1211 Genève 6 , Switzerland (institutional address; updated 27 Oct 2011)
UBE: University of Bern, University of Bern, Hochschulstrasse 4, CH-3012 Bern, Switzerland (institutional address)
Catalogs:
References: Published in Meteoritical Bulletin, no. 94, MAPS 43, 1551-1588 (2008)
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Photos:
CreditPhotos
Photos from the Encyclopedia of Meteorites:
Peter Marmet      
Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
Achim Faforke   
Aeroliths Collection Theodossiou   
ale bartolommei-giulio M.   
Alexander Kovalev   
Allmeteorite.com   
André Knöfel      
Andreas Grünemeyer   
Anthony James         
aranemac   
Argus Rocks   
Aurélien Rombaut   
Auricular                                                                                                                                                                                                                        
Charley Kettel   
christopher brandl   
Collectionspace di Luigi Pizzimenti   
Corey Kuo.   
Darwin Collection of Meteorites   
Dave Gheesling   
Dave Johnson   
David Hardy   
David L. Ribeca      
Dirk Hohmann         
Edward Krikorian   
Él Cuarzo   
Emanuel Henrique Foglietto   
eraserhead            
Franco Vignato      
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Gregor H.               
Hayssam Elbaba      
J John Lutzon   
jdc-meteorite   
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Jim K   
John Harrison   
Jörg-Florian Jensch      
Lucian Hudin   
Luis Alexandre Franco Gonçales      
Marcelo Adorna Fernandes   
Mauricio Beltran   
MeteoriteCollector.org - FCOM - Russ Finney                  
METEORITES AUSTRALIA   
METEORITICON   
Michael Hofmann            
Michael S. Scherman                                                                                                                     
michael sheen   
Mike Smith   
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Paulo Silvio Rubiano   
Raymond Borges   
Rene Schmit      
Robert Zdancewicz      
Roman Jirasek      
Sans      
Svend Buhl      
Takami   
tett         
The Wilcox Collection of Meteorites                     
Troy Carroll                        
Volker Heinrich            
Wandering Star         
Woreczko Jan & Wadi                                             
xeqtr   
Geography:

Mali
Coordinates:
     Recommended::   (23° 41' 47"N, 5° 0' 53"W)

Statistics:
     This is 1 of 4 approved meteorites from Tombouctou, Mali
     This is 1 of 15 approved meteorites from Mali (plus 1 unapproved name)
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