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Sahara 99555 meteorite, Sahara Desert, North Africai
Regional Level Types
Sahara 99555 meteoriteMeteorite Fall Location
Sahara DesertDesert
North Africa- not defined -

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Locality type:Meteorite Fall Location
Meteorite Class:Angrite meteorite
Meteoritical Society Class:Angrite
Metbull:View entry in Meteoritical Bulletin Database


Sahara 99555 (1999 find), 2.71 kg
Angrite, quenched
2nd most massive Angrite

The Sahara 99555 meteorite, recovered somewhere south of the Mediterranean Sea and north of the Equator, is an igneous rock rich in somewhat variable Olivine (~40%), Anorthite (~33%), Fassaite (~25%) and several minor constituents. Skeletal olivine and plagioclase crystals, among other features, suggest that it is a product of a rapidly cooling magma. Bulk Chemical considerations and specific mineralogical features (Kirschtenite, Ti-rich magnetite, etc.) mark Sahara 99555 as an Angrite, a relatively rare achondrite class with only 22 known members representing no more than 15 separate falls. Fortuitously enough, Sahara 99555 and D’Orbigny, the two largest angrites, appear to be compositionally identical with differences between the two being less than the inherent variability with the individual meteorites. Sahara 99555 is also remarkably free of most normal weathering products expected for a meteorite recovered without being observed to fall.

While some new mineralogical phases and features have been subsequently discovered, Mittlefehldt et al., (2002) have presented clear and detailed considerations which indicate the likelihood of a rather large original Angrite parent body (APB) — perhaps larger even than Vesta, the putative source of most Howardite-Eucrite-Diogenite (HED) meteorites. Recent studies have derived a ~4.563 billion year crystallization age for Sahara 99555 and a few of the Angrites. Others appear to be about 5 million years younger. One suggested explanation for these age differences is that Sahara 99555 and the other older Angrites crystallized closer to the surface than the other, more plutonic angrites which were insulated well beneath the surface of the APB.

Select Mineral List Type

Standard Detailed Strunz Dana Chemical Elements

Mineral List


10 valid minerals.

Meteorite/Rock Types Recorded

Note: this is a very new system on mindat.org and data is currently VERY limited. Please bear with us while we work towards adding this information!

Select Rock List Type

Alphabetical List Tree Diagram

Detailed Mineral List:

'Albite-Anorthite Series'
Description: Huge plagioclase laths (~ 1 mm in length)
Reference: Mikouchi, T., McKay, G., Le, L. & Mittlefehldt, D. W. (200O) Preliminary Examination of Sahara 99555: Mineralogy and Experimental Studies of a New Angrite (abstract). Lunar and Planetary Science XXXI. abstract no. 1970. (March 2000)
'Angrite meteorite'
Reference: Meteoritical Society Database
Anorthite
Formula: Ca(Al2Si2O8)
Reference: Grossman, J. N. & Zipfel, J. (2000). The Meteoritical Bulletin, No. 84, 2000 September. Meteoritics & Planetary Science 35(9,Supplement): A199-A225.; Mikouchi, T., McKay, G., Le, L. & Mittlefehldt, D. W. (200O) Preliminary Examination of Sahara 99555: Mineralogy and Experimental Studies of a New Angrite (abstract). Lunar and Planetary Science XXXI. abstract no. 1970. (March 2000); Floss, C., Crozaz, G., McKay, G., Mikouchi, T. & Killgore, M. (2003) Petrogenesis of angrites. Geochimica et Cosmochimica Acta 67(24): 4775-4789. (Dec 2003)
Augite
Formula: (CaxMgyFez)(Mgy1Fez1)Si2O6
Reference: Grossman, J. N. & Zipfel, J. (2000). The Meteoritical Bulletin, No. 84, 2000 September. Meteoritics & Planetary Science 35(9,Supplement): A199-A225.; Mikouchi, T., McKay, G., Le, L. & Mittlefehldt, D. W. (200O) Preliminary Examination of Sahara 99555: Mineralogy and Experimental Studies of a New Angrite (abstract). Lunar and Planetary Science XXXI. abstract no. 1970. (March 2000)
Augite var: Fassaite
Formula: (Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6]
Reference: Grossman, J. N. & Zipfel, J. (2000). The Meteoritical Bulletin, No. 84, 2000 September. Meteoritics & Planetary Science 35(9,Supplement): A199-A225.; Mikouchi, T., McKay, G., Le, L. & Mittlefehldt, D. W. (200O) Preliminary Examination of Sahara 99555: Mineralogy and Experimental Studies of a New Angrite (abstract). Lunar and Planetary Science XXXI. abstract no. 1970. (March 2000)
'Clinopyroxene Subgroup'
Reference: Floss, C., Crozaz, G., McKay, G., Mikouchi, T. & Killgore, M. (2003) Petrogenesis of angrites. Geochimica et Cosmochimica Acta 67(24): 4775-4789. (Dec 2003)
Fayalite
Formula: Fe2+2SiO4
Reference: Floss, C., Crozaz, G., McKay, G., Mikouchi, T. & Killgore, M. (2003) Petrogenesis of angrites. Geochimica et Cosmochimica Acta 67(24): 4775-4789. (Dec 2003)
'Fayalite-Forsterite Series'
Description: skeletal olivine (& plagioclase) crystals suggest rapid cooling magma, Frequently zoned with Mg-free rims of Ca-rich Fayalite and Kirschteinite
Reference: Grossman, J. N. & Zipfel, J. (2000). The Meteoritical Bulletin, No. 84, 2000 September. Meteoritics & Planetary Science 35(9,Supplement): A199-A225.; Mikouchi, T., McKay, G., Le, L. & Mittlefehldt, D. W. (200O) Preliminary Examination of Sahara 99555: Mineralogy and Experimental Studies of a New Angrite (abstract). Lunar and Planetary Science XXXI. abstract no. 1970. (March 2000); Floss, C., Crozaz, G., McKay, G., Mikouchi, T. & Killgore, M. (2003) Petrogenesis of angrites. Geochimica et Cosmochimica Acta 67(24): 4775-4789. (Dec 2003)
Hedenbergite
Formula: CaFe2+Si2O6
Reference: Keil, K. (2012) Angrites, a small but diverse suite of ancient, silica-undersaturated volcanic-plutonic mafic meteorites, and the history of their parent asteroid: Chemie der Erde, geochemistry 71:191-218.
Kirschsteinite
Formula: CaFe2+SiO4
Description: Interstitial
Reference: Grossman, J. N. & Zipfel, J. (2000). The Meteoritical Bulletin, No. 84, 2000 September. Meteoritics & Planetary Science 35(9,Supplement): A199-A225.; Floss, C., Crozaz, G., McKay, G., Mikouchi, T. & Killgore, M. (2003) Petrogenesis of angrites. Geochimica et Cosmochimica Acta 67(24): 4775-4789. (Dec 2003)
Magnetite
Formula: Fe2+Fe3+2O4
Description: Magnetite is usually Ti-rich, characteritic of most Angrites
Reference: Mikouchi, T., McKay, G., Le, L. & Mittlefehldt, D. W. (200O) Preliminary Examination of Sahara 99555: Mineralogy and Experimental Studies of a New Angrite (abstract). Lunar and Planetary Science XXXI. abstract no. 1970. (March 2000); Floss, C., Crozaz, G., McKay, G., Mikouchi, T. & Killgore, M. (2003) Petrogenesis of angrites. Geochimica et Cosmochimica Acta 67(24): 4775-4789. (Dec 2003)
Rhönite
Formula: Ca2(Mg,Fe2+,Fe3+,Ti)6[O2|(Si,Al)6O18]
Description: No Ferric iron, Al deficiency in tetrahedral site; similar to Rhönite in D'Orbigny angite. Rhönite is quite rare in meteorites.
Reference: Jambon, A. & Boudouma, O. (2011). Evidence for Rhönite in Angrites D'Orbigny and Sahara 99555: 74th Annual Meeting of the Meteoritical Society. Meteoritics & Planetary Science Supplement, id.5167. (Sept 2011)
Spinel
Formula: MgAl2O4
Reference: Floss, C., Crozaz, G., McKay, G., Mikouchi, T. & Killgore, M. (2003) Petrogenesis of angrites. Geochimica et Cosmochimica Acta 67(24): 4775-4789. (Dec 2003)
Troilite
Formula: FeS
Description: Traces only
Reference: Mikouchi, T., McKay, G., Le, L. & Mittlefehldt, D. W. (200O) Preliminary Examination of Sahara 99555: Mineralogy and Experimental Studies of a New Angrite (abstract). Lunar and Planetary Science XXXI. abstract no. 1970. (March 2000); Floss, C., Crozaz, G., McKay, G., Mikouchi, T. & Killgore, M. (2003) Petrogenesis of angrites. Geochimica et Cosmochimica Acta 67(24): 4775-4789. (Dec 2003)
Tsangpoite
Formula: Ca5(PO4)2(SiO4)
Reference: Hwang, S. L., Shen, P., Chu, H. T., Yui, T. F., Varela, M. E., & Iizuka, Y. (2016, March). Tsangpoite: The Unknown Calcium Silico Phosphate Phase in the Angrite D'Orbigny. In Lunar and Planetary Science Conference (Vol. 47, p. 1466).

List of minerals arranged by Strunz 10th Edition classification

Group 2 - Sulphides and Sulfosalts
Troilite2.CC.10FeS
Group 4 - Oxides and Hydroxides
Magnetite4.BB.05Fe2+Fe3+2O4
Spinel4.BB.05MgAl2O4
Group 9 - Silicates
'Anorthite'9.FA.35Ca(Al2Si2O8)
'Augite'9.DA.15(CaxMgyFez)(Mgy1Fez1)Si2O6
var: Fassaite9.DA.15(Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6]
Fayalite9.AC.05Fe2+2SiO4
Hedenbergite9.DA.15CaFe2+Si2O6
Kirschsteinite9.AC.05CaFe2+SiO4
Rhönite9.DH.40Ca2(Mg,Fe2+,Fe3+,Ti)6[O2|(Si,Al)6O18]
Unclassified Minerals, Rocks, etc.
'Albite-Anorthite Series'-
'Angrite meteorite'-
'Clinopyroxene Subgroup'-
Fayalite-Forsterite Series-
Tsangpoite-Ca5(PO4)2(SiO4)

List of minerals arranged by Dana 8th Edition classification

Group 2 - SULFIDES
AmXp, with m:p = 1:1
Troilite2.8.9.1FeS
Group 7 - MULTIPLE OXIDES
AB2X4
Magnetite7.2.2.3Fe2+Fe3+2O4
Spinel7.2.1.1MgAl2O4
Group 51 - NESOSILICATES Insular SiO4 Groups Only
Insular SiO4 Groups Only with all cations in octahedral [6] coordination
Fayalite51.3.1.1Fe2+2SiO4
Kirschsteinite51.3.2.2CaFe2+SiO4
Group 65 - INOSILICATES Single-Width,Unbranched Chains,(W=1)
Single-Width Unbranched Chains, W=1 with chains P=2
Augite65.1.3a.3(CaxMgyFez)(Mgy1Fez1)Si2O6
Hedenbergite65.1.3a.2CaFe2+Si2O6
Group 69 - INOSILICATES Chains with Side Branches or Loops
Chains with Side Branches or Loops with P>2
Rhönite69.2.1a.5Ca2(Mg,Fe2+,Fe3+,Ti)6[O2|(Si,Al)6O18]
Unclassified Minerals, Rocks, etc.
'Albite-Anorthite Series'-
'Angrite meteorite'-
Anorthite-Ca(Al2Si2O8)
Augite
var: Fassaite
-(Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6]
'Clinopyroxene Subgroup'-
'Fayalite-Forsterite Series'-
Tsangpoite-Ca5(PO4)2(SiO4)

List of minerals for each chemical element

OOxygen
O AnorthiteCa(Al2Si2O8)
O Augite(CaxMgyFez)(Mgy1Fez1)Si2O6
O Augite (var: Fassaite)(Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6]
O FayaliteFe22+SiO4
O HedenbergiteCaFe2+Si2O6
O KirschsteiniteCaFe2+SiO4
O MagnetiteFe2+Fe23+O4
O RhöniteCa2(Mg,Fe2+,Fe3+,Ti)6[O2|(Si,Al)6O18]
O SpinelMgAl2O4
O TsangpoiteCa5(PO4)2(SiO4)
NaSodium
Na Augite (var: Fassaite)(Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6]
MgMagnesium
Mg Augite(CaxMgyFez)(Mgy1Fez1)Si2O6
Mg Augite (var: Fassaite)(Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6]
Mg RhöniteCa2(Mg,Fe2+,Fe3+,Ti)6[O2|(Si,Al)6O18]
Mg SpinelMgAl2O4
AlAluminium
Al AnorthiteCa(Al2Si2O8)
Al Augite (var: Fassaite)(Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6]
Al RhöniteCa2(Mg,Fe2+,Fe3+,Ti)6[O2|(Si,Al)6O18]
Al SpinelMgAl2O4
SiSilicon
Si AnorthiteCa(Al2Si2O8)
Si Augite(CaxMgyFez)(Mgy1Fez1)Si2O6
Si Augite (var: Fassaite)(Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6]
Si FayaliteFe22+SiO4
Si HedenbergiteCaFe2+Si2O6
Si KirschsteiniteCaFe2+SiO4
Si RhöniteCa2(Mg,Fe2+,Fe3+,Ti)6[O2|(Si,Al)6O18]
Si TsangpoiteCa5(PO4)2(SiO4)
PPhosphorus
P TsangpoiteCa5(PO4)2(SiO4)
SSulfur
S TroiliteFeS
CaCalcium
Ca AnorthiteCa(Al2Si2O8)
Ca Augite(CaxMgyFez)(Mgy1Fez1)Si2O6
Ca Augite (var: Fassaite)(Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6]
Ca HedenbergiteCaFe2+Si2O6
Ca KirschsteiniteCaFe2+SiO4
Ca RhöniteCa2(Mg,Fe2+,Fe3+,Ti)6[O2|(Si,Al)6O18]
Ca TsangpoiteCa5(PO4)2(SiO4)
TiTitanium
Ti Augite (var: Fassaite)(Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6]
Ti RhöniteCa2(Mg,Fe2+,Fe3+,Ti)6[O2|(Si,Al)6O18]
FeIron
Fe Augite(CaxMgyFez)(Mgy1Fez1)Si2O6
Fe Augite (var: Fassaite)(Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6]
Fe FayaliteFe22+SiO4
Fe HedenbergiteCaFe2+Si2O6
Fe KirschsteiniteCaFe2+SiO4
Fe MagnetiteFe2+Fe23+O4
Fe RhöniteCa2(Mg,Fe2+,Fe3+,Ti)6[O2|(Si,Al)6O18]
Fe TroiliteFeS

References

Sort by

Year (asc) Year (desc) Author (A-Z) Author (Z-A)
Grossman, J. N. & Zipfel, J. (2000). The Meteoritical Bulletin, No. 84, 2000 September. Meteoritics & Planetary Science 35(9,Supplement): A199-A225.
Mikouchi, T., McKay, G., Le, L. & Mittlefehldt, D. W. (200O) Preliminary Examination of Sahara 99555: Mineralogy and Experimental Studies of a New Angrite (abstract). Lunar and Planetary Science XXXI. abstract no. 1970. (March 2000)
Bischoff, A., Clayton, R. N., Markl, G., Mayeda, T. K., Palme, H., Schultz, L., Srinivasan, G., Weber, H. W., Weckwerth, G. & Wolf, D. (2000) Mineralogy, Chemistry, Noble Gases, and Oxygen- and Magnesium-Isotopic Compositions of the Angrite Sahara 99555: Meteoritics & Planetary Science 35 (5, Supplement): A27. (July 2000)
Floss, C., Crozaz, G. & Mikouchi, T. (2000) Sahara 99555: Trace-Element Compositions and Relationship to Antarctic Angrites. Meteoritics & Planetary Science 35 (5,Supplement): A53. (July 2000)
Mittlefehldt, D. W., Killgore, M. & Lee, M. T. (2002) Petrology and geochemistry of D'Orbigny, geochemistry of Sahara 99555, and the origin of angrites: Meteoritics & Planetary Science 37 (3): 345-369. (March 2002)
Floss, C., Crozaz, G., McKay, G., Mikouchi, T. & Killgore, M. (2003) Petrogenesis of angrites. Geochimica et Cosmochimica Acta 67(24): 4775-4789. (Dec 2003)
Connelly, J. N., Bizzarro, M., Thrane, K. & Baker, J. A. (2008) The Pb Pb age of Angrite SAH99555 revisited: Geochimica et Cosmochimica Acta 72 (19): 4813-4824. (Oct 2008)
Spivak-Birndorf, L., Wadhwa, M. & Janney, P. (2009) 26Al-26Mg systematics in D’Orbigny and Sahara 99555 angrites: Implications for high-resolution chronology using extinct chronometers. Geochimica et Cosmochimica Acta 73 (17): 5202-5211. (Sept 2009)
Jambon, A. & Boudouma, O. (2011). Evidence for Rhönite in Angrites D'Orbigny and Sahara 99555: 74th Annual Meeting of the Meteoritical Society. Meteoritics & Planetary Science Supplement, id.5167. (Sept 2011)
Keil, K. (2012) Angrites, a small but diverse suite of ancient, silica-undersaturated volcanic-plutonic mafic meteorites, and the history of their parent asteroid: Chemie der Erde, geochemistry 71:191-218.

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