Northwest Africa 2653
Primitive Ungrouped Achondrite
Found 2004
Morocco



Perhaps the Key to unlocking the CV parent body and other failed planets, this meteorite is one of the most important new finds if this century. After the fall of Allende, many questions were answered about CV meteorite origin, but many more remained. NWA 2653 and its pairings are offering a whole new outlook on the nature of this and other failed planets. You need not look far to find numerous abstracts from major universities and institutions, here are a couple:

Northern Arizona University This material is fully authenticated.

Description and classification ( T. Bunch and J. Wittke , NAU ), results from one thin section (2.4 cm 2 ): mostly recrystallized into fine-grained (<0.5 mm, avg. = 0.185 mm) polygonal and subhedral grains with the exception of several medium to large (1.2 3.0 mm) orthopyroxene grains that contain very small olivine (<0.1 mm) inclusions. Very homogeneous assemblage, olivine and orthopyroxene analyses are within the precision of the electron microprobe (± 0.15 mol %). Olivine, Fa 18.9 (FeO/MnO = 38.1 g/g); orthopyroxene, Fs 16.8 Wo 2.9 (FeO/MnO = 20.0 g/g); plagioclase, An 15.1 Or 4.7 ; metal (only taenite found), Ni = 18.9 wt. %; chromite (only one grain found), cr# = 84.5; FeS , Ni = 1.42 wt. % and Co = 0.28 wt. %, minor merrillite. Oxygen isotope replicate analyses (D. Rumble, CIW ) of acid washed, bulk sample by lased fluorination gave d 17 O = 3.23 and 2.98, d 18 O = 5.03 and 4.37 and D 17 O = 0.614 and 0.708. Formerly classified as an H7. Weathering grade, W2/3 with staining; shoc k level, S1.

There are several unusual primitive achondrites that apparently are not related to the lodranite-acapulcoite or brachinite parent bodies. Divnoe and Zag (b) are two FeO-rich achondrites that are similar to brachinites, but with different oxygen isotope patterns.  NWA 3133/2653 paired specimens were originally classified as L7 chondrites, but oxygen isotope analyses show that this meteorite is a primitive achondrite whose oxygen isotopes plot on the CV3 mixing line and may represent a melt differentiate of a moderately large CV3 parent body. NWA 011/2400 is very different from other primitive achondrites in having FeO/MnO molecular ratios similar to lunar rocks and oxygen isotopes consistent with CR carbonaceous chondrites. Moreover, the texture is consistent with igneous derivation in contrast with the metamorphic recrystallized textures of most primitive achondrites. Like NWA 3133/2653, this meteorite may also be an igneous melt differentiate of a moderately large CR carbonaceous chondrite parent body.

American Geophysical Union

Oxygen isotopic studies plot on the mixing line for Allende and other CV3 chondrites. Thus, this could be regarded as the first known "CV7 chondrite", and may have been formed by metamorphic recrystallization (or perhaps igneous processes) in the CV parent body.

Our inference from these data is that the CV parent body was an at least partially differentiated (and relatively large) object consisting of a metal+silicate core region surrounded by a presumably silicate-rich mantle and a chondrule-CAI-rich regolith, the deepest portions of which were metamorphosed and/or partially melted to form primitive achondritic lithologies.

These slices and endcuts are polished to 4 microns, ready for the probe as is. As such, they are very difficult to photograph.

Click on images below to enlarge


Northwest Africa 2653 Ungrouped Primitive Achondrite
15.07 gram endcut. 
$600.00

Northwest Africa 2653 Ungrouped Primitive Achondrite
6.25 gram slice. 
$250.00

Northwest Africa 2653 Ungrouped Primitive Achondrite
6.06 gram slice. 
$240.00

Northwest Africa 2653 Ungrouped Primitive Achondrite
4.76 gram endcut. 
$190.00

Northwest Africa 2653 Ungrouped Primitive Achondrite
4.57 gram slice. 
$185.00

Northwest Africa 2653 Ungrouped Primitive Achondrite
4.52 gram slice. 
$180.00

Northwest Africa 2653 Ungrouped Primitive Achondrite
4.16 gram slice. 
$170.00

Northwest Africa 2653 Ungrouped Primitive Achondrite
Group shot on angle to show matrix

Northwest Africa 2653 Ungrouped Primitive Achondrite
Click the image for microphotographs courtesty of Tom Phillips
Free CD-ROM with purchase

 
For ordering information please click HERE

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