Gallery


CV - CO3 - CM2 - CI - CR - CK - CH

Vigarano - Ornans - Mighei - Ivuna
Renazzo - Karoonda type
 The first recognized specimen for each type gives the second letter.



CO3 complete individual in situ (8300gr)
CO3
Dar al Gani CO3 more probably 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, 229, 230, 231, 289, 291, 331, 332, 601, 667, 668, 749, 845, 846, 847, 848, 852, 853, 854, 858, 998, 1006...

The Dar al Gani 749 meteorite find (referred to the largest mass number) and the Kainsaz fall are the two most important CO3 recovered.



Carbonaceous chondrites are a rare kind of meteorite that contain organic compounds such as amino acids and kerogin, an organic matter often found in coal and shale.
Instead of containing the anhydrous silicates found in most chondrites, the carbonaceous types have claylike hydrous silicate minerals. They also contain carbonate and sulfate minerals, iron oxides, and sulfur. Magnesium sulfate is found in narrow veins.



Metal droplets in Dar al Gani 749, CO3, photo: E. Dransart EMTT

Carbonaceous chondrites represent some of the most primitive of all meteorites, with solar major element composition (Fe, Si, Mg, Ca, Al).
They are intensely studied.




 metal droplets




  • There are seven groups of Carbonaceous meteorites:

    • CV, well known with the Allende fall in 1969 (+2000 kg)
    • CO3, Kainsaz and Dar al Gani 749 are the most important
    • CM2, like Murchison, many falls have been observed
    • CI, the most friable (Orgueil)
    • CR, Acfer and El Djouf
    • CK, Hammada al Hamra 280
    • CH, new chondritic group (earlier labeled Bencubbinite)



    CO chondrites show Petrologic subtypes from 3.0 (ALH A77307) to 3.7, with 6% by weight of metal, only 20 to 30 percent matrix, they appear full of chondrules.



    - The CO carbonaceous chondrites are petrologic type 3, they display a variety of very well defined chondrules closely packed together.
    - Inclusions of iron-nickel are visible scattered throughout the meteorite.
    - CO chondrites are rarer than CV, with an observed chondrite fall rate of only 1 percent.



    CI, CM, CR chondrites show the effects of aqueous alteration at low temperatures, that imply an oxygen-rich and cold environment.



    Metal in CR chondrite is found in the fine grained matrix and as inclusions in the chondrules
    CR chondrite





    Ca-Al Inclusion from CO3 carbonaceous chondrite
    photo: E. Dransart EMTT
    CAIs Refractory inclusions, CAIs (Calcium Aluminium Inclusions) are found in certain groups of carbonaceous chondrites, like CV and CO.

    Made of silicate and oxide rich calcium aluminium minerals, they crystallize at high temperatures.




    CK chondrites show various degrees of metamorphism. They are close to CV and were earlier labeled CV4 or CV5


    CK chondrite from Dar al Gani
    CK chondrite





    CH is a new group of Carbonaceous chondrites. They have the highest percentage of metal of all Carbonaceous groups.

    CH chondrites are characterized by a FeNi-metal-rich nature and a general paucity of matrix around the chondrules.



    SaharaMet expedition 2001
    CH chondrite




    Carbonaceous chondrites are aesthetic meteorites. The seven groups differ widely from each other and are intensely studied. Some are very rare meteorites, like CI or CH, others are available at low price, like CV or CO.

    Some samples from the above specimens are available for collectors and researchers on request.




    Find all the reference cards in printable definition on the
    SaharaMet 2004 Cd-Rom
    Acfer 324 - CR
    Dar al Gani 974 - CR




    Ureilites, Dar al Gani