Fall 8 Aug 1933, Daytime fireball
Eucrite, monomict; 4.1 kg

After a daytime fireball was accompanied by detonations heard over a 250 km swath only twenty-odd small stones were eventually recovered. Sioux County's main constituents are a brecciated mix of abundant pyroxene accompanied by slightly less abundant anorthitic plagioclase. Pigeonite - with exolved augite - is the most conspicuous pyroxene. However, orthopyroxene predominates in some portions of the meteorite. Minor phases include other silicates and opaques — including some unusual Ni-poor iron found only in a few meteorite classes.

Sioux County is an ancient, brecciated rock whose primary components — like those of most Howardites, Eucrites, and Diogenites (HED Achondrites) — once lay near each other on or beneath the surface of a moderately large asteroid (apparently Vesta). In time chance, circumstance, and collisions have brought a small fraction of such stones into the earth's atmosphere and into the hands of humans.

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Standard Detailed Gallery Strunz Chemical Elements

Mineral List

8 valid minerals.

Meteorite/Rock Types Recorded

Note: data is currently VERY limited. Please bear with us while we work towards adding this information!

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Alphabetical List Tree Diagram

ⓘ 'Eucrite monomict breccia meteorite'

Detailed Mineral List:

ⓘ Augite

Formula: (Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆

Description: Usually as augite lamellae; Warren & Kallemeyn (1994) noted a grain of primary augite

References:

Warren, P. H. & Kallemeyn, G. W. (1994) Sioux County: an orthocumulate, and systematics of V and other trace elements in several similar eucrites. Meteoritics 29 (4): p. 546. (July 1994)

ⓘ Augite var. Ferroaugite

Formula: (Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆

References:

Mason B., Jarosewich E. & Nelen J. A. (1979) The pyroxene-plagioclase achondrites. Smithson. Contrib. Earth Sci. 22: 27-45.

ⓘ Chromite

Formula: Fe²⁺Cr³⁺₂O₄

References:

146-157 (Jan/Feb 1971)

Bunch, T. E., Keil, Klaus (1971) Chromite and ilmenite in non-chondritic meteorites. American Mineralogist, 56 (1-2) 146-157

ⓘ 'Fayalite-Forsterite Series'

Description: Olivine (Fe-rich)

References:

Takeda, H., Nyquist, L. E., Yamaguchi, A., & Miyamoto, M. (1996) Recrystallization of Ca-Rich Phases in Eucrites and Constraints on the Time of the Crustal Metamorphism: Lunar Planetary Science XXVII: 1309-1310. (March 1996)

ⓘ Ilmenite

Formula: Fe²⁺TiO₃

References:

146-157 (Jan/Feb 1971)

Bunch, T. E., Keil, Klaus (1971) Chromite and ilmenite in non-chondritic meteorites. American Mineralogist, 56 (1-2) 146-157

ⓘ Merrillite

Formula: Ca₉NaMg(PO₄)₇

References:

Hsu, W. & Crozaz, G. (1996) Mineral Chemistry and the petrogenesis of eucrites: I. Noncumulate eucrites: Geochimica et Cosmochimica Acta 60 (22): 4571-4591. (Nov 1996)

ⓘ Native Iron

Formula: Fe

Description: Low-Ni iron is a very minor constituent (<1% bulk)

References:

Collinson, D. W. & Morden, S. J. (1992) Magnetic Properties of Some Achondrite Meteorites and Implications for Their Evolution (abstract): Meteoritics 27(3): 211-212. (July 1992)

ⓘ 'Orthopyroxene Subgroup'

Description: A primary phase in some instances

References:

Duke, Michael B., Silver, Leon T. (1967) Petrology of eucrites, howardites and mesosiderites. Geochimica et Cosmochimica Acta, 31 (10) 1637-1665 doi:10.1016/0016-7037(67)90112-3

Warren, P. H. & Kallemeyn, G. W. (1994) Sioux County: an orthocumulate, and systematics of V and other trace elements in several similar eucrites. Meteoritics 29 (4): p. 546. (July 1994)

ⓘ Pigeonite

Formula: (Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆

References:

Mason, Brian (1967) The Bununu meteorite, and a discussion of the pyroxene-plagioclase achondrites. Geochimica et Cosmochimica Acta, 31 (2) 107-115 doi:10.1016/s0016-7037(67)80040-1

Duke, Michael B., Silver, Leon T. (1967) Petrology of eucrites, howardites and mesosiderites. Geochimica et Cosmochimica Acta, 31 (10) 1637-1665 doi:10.1016/0016-7037(67)90112-3

ⓘ 'Plagioclase'

Formula: (Na,Ca)[(Si,Al)AlSi₂]O₈

Description: Plagioclase [An90](Duke & Silver,1967)

References:

Duke, Michael B., Silver, Leon T. (1967) Petrology of eucrites, howardites and mesosiderites. Geochimica et Cosmochimica Acta, 31 (10) 1637-1665 doi:10.1016/0016-7037(67)90112-3

Mason B., Jarosewich E. & Nelen J. A. (1979) The pyroxene-plagioclase achondrites. Smithson. Contrib. Earth Sci. 22: 27-45.

ⓘ 'Pyroxene Group'

Formula: ADSi₂O₆

Description: Anhedral pyroxene encloses plagioclase grains in many instances

References:

Mittlefehldt, D. W., Jones, J. H., Palme, H., Jarosewich, E. & Grady, M. M. (1998) Sioux County - A Study in Why Sleeping Dogs are Best Left Alone: Lunar Planetary Science XXIX: Abstract no. 1220. (March 1998)

ⓘ Tridymite

Formula: SiO₂

References:

Duke, Michael B., Silver, Leon T. (1967) Petrology of eucrites, howardites and mesosiderites. Geochimica et Cosmochimica Acta, 31 (10) 1637-1665 doi:10.1016/0016-7037(67)90112-3

ⓘ Troilite

Formula: FeS

Description: Troilite quite abundant for basaltic eucrites

References:

Gallery:

List of minerals arranged by Strunz 10th Edition classification

Group 1 - Elements
ⓘ	Native Iron	1.AE.05	Fe
Group 2 - Sulphides and Sulfosalts
ⓘ	Troilite	2.CC.10	FeS
Group 4 - Oxides and Hydroxides
ⓘ	Chromite	4.BB.05	Fe²⁺Cr³⁺₂O₄
ⓘ	Ilmenite	4.CB.05	Fe²⁺TiO₃
ⓘ	Tridymite	4.DA.10	SiO₂
Group 8 - Phosphates, Arsenates and Vanadates
ⓘ	Merrillite	8.AC.45	Ca₉NaMg(PO₄)₇
Group 9 - Silicates
ⓘ	Pigeonite	9.DA.10	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
ⓘ	Augite	9.DA.15	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
ⓘ	var. Ferroaugite	9.DA.15	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Unclassified
ⓘ	'Fayalite-Forsterite Series'	-
ⓘ	'Plagioclase'	-	(Na,Ca)[(Si,Al)AlSi₂]O₈
ⓘ	'Pyroxene Group'	-	ADSi₂O₆
ⓘ	'Orthopyroxene Subgroup'	-

List of minerals for each chemical element

O	Oxygen
O	ⓘ Augite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
O	ⓘ Chromite	Fe²⁺Cr₂³⁺O₄
O	ⓘ Ilmenite	Fe²⁺TiO₃
O	ⓘ Pigeonite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
O	ⓘ Tridymite	SiO₂
O	ⓘ Merrillite	Ca₉NaMg(PO₄)₇
O	ⓘ Fayalite-Forsterite Series
O	ⓘ Plagioclase	(Na,Ca)[(Si,Al)AlSi₂]O₈
O	ⓘ Pyroxene Group	ADSi₂O₆
O	ⓘ Augite var. Ferroaugite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Na	Sodium
Na	ⓘ Merrillite	Ca₉NaMg(PO₄)₇
Na	ⓘ Plagioclase	(Na,Ca)[(Si,Al)AlSi₂]O₈
Mg	Magnesium
Mg	ⓘ Augite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Mg	ⓘ Pigeonite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Mg	ⓘ Merrillite	Ca₉NaMg(PO₄)₇
Mg	ⓘ Fayalite-Forsterite Series
Mg	ⓘ Augite var. Ferroaugite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Al	Aluminium
Al	ⓘ Plagioclase	(Na,Ca)[(Si,Al)AlSi₂]O₈
Si	Silicon
Si	ⓘ Augite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Si	ⓘ Pigeonite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Si	ⓘ Tridymite	SiO₂
Si	ⓘ Fayalite-Forsterite Series
Si	ⓘ Plagioclase	(Na,Ca)[(Si,Al)AlSi₂]O₈
Si	ⓘ Pyroxene Group	ADSi₂O₆
Si	ⓘ Augite var. Ferroaugite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
P	Phosphorus
P	ⓘ Merrillite	Ca₉NaMg(PO₄)₇
S	Sulfur
S	ⓘ Troilite	FeS
Ca	Calcium
Ca	ⓘ Augite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Ca	ⓘ Pigeonite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Ca	ⓘ Merrillite	Ca₉NaMg(PO₄)₇
Ca	ⓘ Plagioclase	(Na,Ca)[(Si,Al)AlSi₂]O₈
Ca	ⓘ Augite var. Ferroaugite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Ti	Titanium
Ti	ⓘ Ilmenite	Fe²⁺TiO₃
Cr	Chromium
Cr	ⓘ Chromite	Fe²⁺Cr₂³⁺O₄
Fe	Iron
Fe	ⓘ Augite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Fe	ⓘ Chromite	Fe²⁺Cr₂³⁺O₄
Fe	ⓘ Ilmenite	Fe²⁺TiO₃
Fe	ⓘ Native Iron	Fe
Fe	ⓘ Pigeonite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Fe	ⓘ Troilite	FeS
Fe	ⓘ Fayalite-Forsterite Series
Fe	ⓘ Augite var. Ferroaugite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆

Other Regions, Features and Areas containing this locality

North AmericaContinent

North America PlateTectonic Plate

Great Plains DomainDomain
Yavapai TerraneVolcanic Arc

This page contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.

References

www.lpi.usra.edu (n.d.) http://www.lpi.usra.edu/meteor/get_original_photo.php?recno=5631940

Mason, Brian (1967) The Bununu meteorite, and a discussion of the pyroxene-plagioclase achondrites. Geochimica et Cosmochimica Acta, 31 (2) 107-115 doi:10.1016/s0016-7037(67)80040-1

Duke, Michael B., Silver, Leon T. (1967) Petrology of eucrites, howardites and mesosiderites. Geochimica et Cosmochimica Acta, 31 (10) 1637-1665 doi:10.1016/0016-7037(67)90112-3

Bunch, T. E., Keil, Klaus (1971) Chromite and ilmenite in non-chondritic meteorites. American Mineralogist, 56 (1-2) 146-157

Nininger, H. H. (1972) Find a Falling Star: Paul S. Eriksson, Inc., New York. 254 pages, paper.

Mason B., Jarosewich E. & Nelen J. A. (1979) The pyroxene-plagioclase achondrites. Smithson. Contrib. Earth Sci. 22: 27-45.

Collinson, D. W. & Morden, S. J. (1992) Magnetic Properties of Some Achondrite Meteorites and Implications for Their Evolution (abstract): Meteoritics 27(3): 211-212. (July 1992)

Warren, P. H. & Kallemeyn, G. W. (1994) Sioux County: an orthocumulate, and systematics of V and other trace elements in several similar eucrites. Meteoritics 29 (4): p. 546. (July 1994)

Hsu, W. & Crozaz, G. (1996) Mineral Chemistry and the petrogenesis of eucrites: I. Noncumulate eucrites: Geochimica et Cosmochimica Acta 60 (22): 4571-4591. (Nov 1996)

Mittlefehldt, D. W., McCoy, T. J., Goodrich, C. A. & Kracher, A. (1998). Non-chondritic meteorites from asteroidal bodies. In: Planetary Materials (Papike, J. J., Editor): Chapter 4, 398 pages. Mineralogical Society of America: Washington, DC, USA. (1998)

Grady, Monica (2000) Catalogue of Meteorites (5th ed.). Cambridge University Press.

www.lpi.usra.edu (n.d.) http://www.lpi.usra.edu/meteor/metbull.php

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Sioux County meteorite, Sioux County, Nebraska, USAiRegional Level TypesSioux County meteoriteMeteorite Fall Location Sioux CountyCounty NebraskaState USACountry

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Mineral List

Meteorite/Rock Types Recorded

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Detailed Mineral List:

Gallery:

List of minerals arranged by Strunz 10th Edition classification

List of minerals for each chemical element

Other Regions, Features and Areas containing this locality

References

Sioux County meteorite, Sioux County, Nebraska, USA i
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Sioux County meteorite Meteorite Fall Location
Sioux County County
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