0.627g ERG ATOUILA 001 Ungrouped Achondrite Meteorite
On Offer: 0.627 gram slice of Erg Atouila 001 Achondrite-ung
Official Name: Erg Atouila 001
Abbreviation: EA 001
Classification: Achondrite Ungrouped - this is a truly unique ungrouped potassium rich meteorite from an unknown differentiated parent body. Composed almost entirely of albitic plagioclase, it's oxygen isotope profile " plot near the acapulcoite-lodranite field" according to the classification, however there is no petrologic affinity to this group as its modal composition is nothing like these primitive achondrites, but rather closer to a particular type of ureilite known as a "trachyte".
Thus the ungrouped classification, as it doesn't fall into any existing taxonomical meteorite group. This is among the most interesting and unique of the newly emerging ungrouped achondrites. These types of achondrites are helping us understand the dynamics of early accretion and solar system formation and at times forcing us to adjust well establish chronologies and models.
These particular specimens show significant shock darkening, and the occasional small olive green phenocryst as well as bright kamacite (metal) blebs. The large grain size described in the classification can easily be seen in these specimens. We only have a few grams of this material. These piece that these slices and end cuts were made from was sent to us directly from Mr. Aide, the main mass holder.
Year found: 2020
Country: Mali
Description: Slice of an amazing ungrouped achondritic meteorite with official name Erg Atouila 001.
What you get: 0.627 gram Erg Atouila 001 specimen as shown, shipping/storage membrane box, and signed Certificate of Authenticity.
We offer a 100% no questions asked 30 day return policy.
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| Basic information |
Name: Erg Atouila 001 This is an OFFICIAL meteorite name. Abbreviation: EA 001 Observed fall: No Year found: 2020 Country: Mali Mass:  793 g |
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| Classification history: |
This is 1 of 131 approved meteorites classified as Achondrite-ung. [show all] Search for other: Achondrites, Ungrouped achondrites |
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| Comments: | Approved 19 Dec 2021 | ||||||||||||||||||||||||||||||||||||
| Writeup |
Writeup from MB 110:
Erg Atouila 001 (EA 001) 22.489944, -4.551744 Gao, Mali Find: 2020 Classification: Ungrouped achondrite History: The first piece of 553 g was found by a nomad in August 2020. A second piece of 240 g was found less than a km from the first piece location in September 2020. Both pieces were purchased by Mohamed Aid. Physical characteristics: Two similar appearing pieces, 553 and 240 g. Exterior is dominated by a pink to light orange color with some dark gray patches with oxidation halos, and some small green patches are scattered throughout. No fusion crust is present. Several dark-colored shock melt veinlets are visible. Petrography: (M. Spilde, A. Ross, C. Agee, UNM) Microprobe examination and an SEM survey show that albitic alkali feldspar makes up 95% of the modal abundance of this meteorite. Clinopyroxene makes up approximately 3% of the mode, phases with less than 1% modal abundance include olivine, K-feldspar, fluorapatite, troilite, Fe-metal, ilmenite, and oxidized iron. Small poikiolitic inclusions of olivine and lamellae of K-spar are ubiquitous within the host albite. Clinopyroxene occurs primarily in centimeter-sized nodules along with olivine inclusions and other minor phases. Geochemistry: (A. Ross, UNM) Albite Ab91.8±0.7Or6.3±1.1An1.9±0.4, n=4; K-feldspar Ab10.2±2.3Or89.3±2.4An0.5±0.1, n=3; high-Ca pyroxene Fs10.0±0.6Wo44.0±0.4, Fe/Mn=9±1, n=10; olivine Fa29.3±0.8, Fe/Mn=20±1, n=3; apatite F=3.2 wt%, Cl=0.13 wt%, iron metal Ni=0.26±0.02 wt%, n=3. Oxygen isotopes (K. Ziegler, UNM): 3 acid-washed fragments analyzed by laser fluorination gave δ18O= 4.789, 4.744, 4.088; δ17O= 1.437, 1.423, 1.074; Δ17O= -1.091, -1.082, -1.084 (linearized, all per mil, TFL slope=0.528). Classification: Ungrouped achondrite (albitite). This meteorite is an albitite with one of the highest modal feldspar contents ever reported in a meteorite – comparable modal abundance to lunar anorthosite meteorites, however its feldspar is an alkali feldspar solid solution. This albitite meteorite is also unlike other Na-feldspar-rich ungrouped achondrites such as GRA 06128/06129 (Shearer et al., 2008) and Almahata Sitta ALMA-A (Bischoff et al., 2014) which have feldspar as plagioclase solid solutions. When plotted on a total alkali-silica (TAS) diagram the bulk composition of this meteorite falls within the trachyte field. Given the relatively coarse grain size present, syenite or olivine syenite are alternative igneous rock names for this meteorite. The oxygen isotope values plot near the acapulcoite-lodranite field although there is no obvious petrologic link between this meteorite and acapulcoites/lodranites. Specimens: 20.5 g on deposit at UNM, Mohamed Aid holds the main mass. |
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| Bibliography: |
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| Data from: MB110 Table 0 Line 0: |
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| Plots: | O isotopes: |
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