Eucrite, cumulate
Fell 21 Apr 1913, 1.88 kg

The Moore County eucrite has remained an object of continuing interest after Hess & Henderson (1949) presented persuasive evidence that the meteorite's primary mineralogical assemblage had involved slow crystallization and subsequent sub-solidus development not unlike that experienced by terrestrial rocks forming at moderate depths below the surface. The stone is dominated by pyroxenes and anorthitic plagioclase. Differences in petrographic descriptions of the pyroxenes is an apparent consequence of the complicated transformation and inversion from an original, oriented Ca-rich pigeonite into (mostly) clinohypersthene accompanied by at least two generations of augite exsolution lamellae. The plagioclase is reported by some observers to be uniform in composition, but minor differences in reported results suggest some compositional variability within the meteorite. Minor phases include interstitial tridymite and lesser amounts of apatite and even apparent primary augite. Opaques include chromite, Ilmenite, troilite and traces of iron.

Primary crystallization apparently occurred ~ 4.55 billion years ago, but reconciling isotopic ages and reconstructing the subsequent sequence of events leading to Moore County's eventual arrival on earth remains a continuing challenge.

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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 cumulate meteorite'

Detailed Mineral List:

ⓘ Anorthite

Formula: Ca(Al₂Si₂O₈)

Description: Plagioclase 91-93

References:

Tera, F., Carlson, R. W. & Boctor, N. Z. (1987) Isotopic and Petrologic Investigation of the Eucrites Cachari, Moore County and Stannern (abstract): Lunar Planetary Science XVIII: p.1004.

ⓘ Anorthite var. Bytownite

Formula: (Ca,Na)[Al(Al,Si)Si₂O₈]

Description: Plagioclase (An88) acccording to Hess & Henderson (1949)

References:

Hess, H. H., Henderson, E. P. (1949) The Moore County meteorite: A further study with comment on its primordial environment. American Mineralogist, 34 (7-8) 494-507

ⓘ 'Apatite'

Formula: Ca₅(PO₄)₃(Cl/F/OH)

References:

Delaney, J. S. (1982) Minor Components of Basaltic Achondrites - II. Phosphorus (abstract): Lunar Planetary Science Conference XIII: 150-151. (March 1982)

Sarafian, A. R., Roden, M. F. & Patiño-Douce, A. E. (2013) The volatile content of Vesta: Clues from apatite in eucrites. Meteoritics & Planetary Science 48 (11): 2135-2154. (Nov 2013)

ⓘ Augite

Formula: (Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆

Description: Complicated exsolution as coarse-grained and fined-grained lamellae and as blebby grains; Small amount of primary augite reported by Nord (1983)

References:

Hess, H. H., Henderson, E. P. (1949) The Moore County meteorite: A further study with comment on its primordial environment. American Mineralogist, 34 (7-8) 494-507

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

Mori, H. & Takeda, H. (1981) Evolution of the Moore County Pyroxenes As Viewed by an Analytical Transmission Electron Microprobe (ATEM). Meteoritics 16 (4): 362-363. (Dec 1981)

Sarafian, A. R., Roden, M. F. & Patiño-Douce, A. E. (2013) The volatile content of Vesta: Clues from apatite in eucrites. Meteoritics & Planetary Science 48 (11): 2135-2154. (Nov 2013)

ⓘ 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

Hostetler, C. J. & Drake, M. J. (1978) Quench temperatures of Moore County and other eucrites: residence time on eucrite parent body. Geochimica et Cosmochimica Acta 42 (5): 517-522. (May 1978)

Sarafian, A. R., Roden, M. F. & Patiño-Douce, A. E. (2013) The volatile content of Vesta: Clues from apatite in eucrites. Meteoritics & Planetary Science 48 (11): 2135-2154. (Nov 2013)

ⓘ 'Hypersthene'

Formula: (Mg,Fe)SiO₃

References:

Hess, H. H., Henderson, E. P. (1949) The Moore County meteorite: A further study with comment on its primordial environment. American Mineralogist, 34 (7-8) 494-507

Mori, H. & Takeda, H. (1981) Evolution of the Moore County Pyroxenes As Viewed by an Analytical Transmission Electron Microprobe (ATEM). Meteoritics 16 (4): 362-363. (Dec 1981)

ⓘ 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

Hostetler, C. J. & Drake, M. J. (1978) Quench temperatures of Moore County and other eucrites: residence time on eucrite parent body. Geochimica et Cosmochimica Acta 42 (5): 517-522. (May 1978)

Sarafian, A. R., Roden, M. F. & Patiño-Douce, A. E. (2013) The volatile content of Vesta: Clues from apatite in eucrites. Meteoritics & Planetary Science 48 (11): 2135-2154. (Nov 2013)

ⓘ Native Iron

Formula: Fe

Description: Ni-poor iron is rare in most meteorites, but is present here in very small amounts.

References:

Hostetler, C. J. & Drake, M. J. (1978) Quench temperatures of Moore County and other eucrites: residence time on eucrite parent body. Geochimica et Cosmochimica Acta 42 (5): 517-522. (May 1978)

ⓘ 'Orthopyroxene Subgroup'

Description: Subhedral/euhedral orthopyroxene w. augite exsolution lamellae (0.2–6 mm wide)

References:

Sarafian, A. R., Roden, M. F. & Patiño-Douce, A. E. (2013) The volatile content of Vesta: Clues from apatite in eucrites. Meteoritics & Planetary Science 48 (11): 2135-2154. (Nov 2013)

ⓘ Pigeonite

Formula: (Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆

Description: Pigeonite is oriented suggesting slow settling environment.

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

Mori, H. & Takeda, H. (1981) Evolution of the Moore County Pyroxenes As Viewed by an Analytical Transmission Electron Microprobe (ATEM). Meteoritics 16 (4): 362-363. (Dec 1981)

ⓘ 'Plagioclase'

Formula: (Na,Ca)[(Si,Al)AlSi₂]O₈

Description: Plagioclase is uniform (Ab9) according to Mason et.al., (1979);Plagioclase (An 91-93)according to Tera et al., (1987), An90–An93 according to Sarafian et al., (2013)

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

Hostetler, C. J. & Drake, M. J. (1978) Quench temperatures of Moore County and other eucrites: residence time on eucrite parent body. Geochimica et Cosmochimica Acta 42 (5): 517-522. (May 1978)

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

Sarafian, A. R., Roden, M. F. & Patiño-Douce, A. E. (2013) The volatile content of Vesta: Clues from apatite in eucrites. Meteoritics & Planetary Science 48 (11): 2135-2154. (Nov 2013)

ⓘ 'Pyroxene Group'

Formula: ADSi₂O₆

References:

Hostetler, C. J. & Drake, M. J. (1978) Quench temperatures of Moore County and other eucrites: residence time on eucrite parent body. Geochimica et Cosmochimica Acta 42 (5): 517-522. (May 1978)

ⓘ Tridymite

Formula: SiO₂

References:

Hess, H. H., Henderson, E. P. (1949) The Moore County meteorite: A further study with comment on its primordial environment. American Mineralogist, 34 (7-8) 494-507

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

Hostetler, C. J. & Drake, M. J. (1978) Quench temperatures of Moore County and other eucrites: residence time on eucrite parent body. Geochimica et Cosmochimica Acta 42 (5): 517-522. (May 1978)

Sarafian, A. R., Roden, M. F. & Patiño-Douce, A. E. (2013) The volatile content of Vesta: Clues from apatite in eucrites. Meteoritics & Planetary Science 48 (11): 2135-2154. (Nov 2013)

ⓘ Troilite

Formula: FeS

References:

Hostetler, C. J. & Drake, M. J. (1978) Quench temperatures of Moore County and other eucrites: residence time on eucrite parent body. Geochimica et Cosmochimica Acta 42 (5): 517-522. (May 1978)

Sarafian, A. R., Roden, M. F. & Patiño-Douce, A. E. (2013) The volatile content of Vesta: Clues from apatite in eucrites. Meteoritics & Planetary Science 48 (11): 2135-2154. (Nov 2013)

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 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
ⓘ	Anorthite	9.FA.35	Ca(Al₂Si₂O₈)
ⓘ	var. Bytownite	9.FA.35	(Ca,Na)[Al(Al,Si)Si₂O₈]
Unclassified
ⓘ	'Hypersthene'	-	(Mg,Fe)SiO₃
ⓘ	'Plagioclase'	-	(Na,Ca)[(Si,Al)AlSi₂]O₈
ⓘ	'Pyroxene Group'	-	ADSi₂O₆
ⓘ	'Orthopyroxene Subgroup'	-
ⓘ	'Apatite'	-	Ca₅(PO₄)₃(Cl/F/OH)

List of minerals for each chemical element

H	Hydrogen
H	ⓘ Apatite	Ca₅(PO₄)₃(Cl/F/OH)
O	Oxygen
O	ⓘ Anorthite	Ca(Al₂Si₂O₈)
O	ⓘ Augite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
O	ⓘ Anorthite var. Bytownite	(Ca,Na)[Al(Al,Si)Si₂O₈]
O	ⓘ Chromite	Fe²⁺Cr₂³⁺O₄
O	ⓘ Hypersthene	(Mg,Fe)SiO₃
O	ⓘ Ilmenite	Fe²⁺TiO₃
O	ⓘ Pigeonite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
O	ⓘ Tridymite	SiO₂
O	ⓘ Plagioclase	(Na,Ca)[(Si,Al)AlSi₂]O₈
O	ⓘ Pyroxene Group	ADSi₂O₆
O	ⓘ Apatite	Ca₅(PO₄)₃(Cl/F/OH)
F	Fluorine
F	ⓘ Apatite	Ca₅(PO₄)₃(Cl/F/OH)
Na	Sodium
Na	ⓘ Anorthite var. Bytownite	(Ca,Na)[Al(Al,Si)Si₂O₈]
Na	ⓘ Plagioclase	(Na,Ca)[(Si,Al)AlSi₂]O₈
Mg	Magnesium
Mg	ⓘ Augite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Mg	ⓘ Hypersthene	(Mg,Fe)SiO₃
Mg	ⓘ Pigeonite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Al	Aluminium
Al	ⓘ Anorthite	Ca(Al₂Si₂O₈)
Al	ⓘ Anorthite var. Bytownite	(Ca,Na)[Al(Al,Si)Si₂O₈]
Al	ⓘ Plagioclase	(Na,Ca)[(Si,Al)AlSi₂]O₈
Si	Silicon
Si	ⓘ Anorthite	Ca(Al₂Si₂O₈)
Si	ⓘ Augite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Si	ⓘ Anorthite var. Bytownite	(Ca,Na)[Al(Al,Si)Si₂O₈]
Si	ⓘ Hypersthene	(Mg,Fe)SiO₃
Si	ⓘ Pigeonite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Si	ⓘ Tridymite	SiO₂
Si	ⓘ Plagioclase	(Na,Ca)[(Si,Al)AlSi₂]O₈
Si	ⓘ Pyroxene Group	ADSi₂O₆
P	Phosphorus
P	ⓘ Apatite	Ca₅(PO₄)₃(Cl/F/OH)
S	Sulfur
S	ⓘ Troilite	FeS
Cl	Chlorine
Cl	ⓘ Apatite	Ca₅(PO₄)₃(Cl/F/OH)
Ca	Calcium
Ca	ⓘ Anorthite	Ca(Al₂Si₂O₈)
Ca	ⓘ Augite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Ca	ⓘ Anorthite var. Bytownite	(Ca,Na)[Al(Al,Si)Si₂O₈]
Ca	ⓘ Pigeonite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Ca	ⓘ Plagioclase	(Na,Ca)[(Si,Al)AlSi₂]O₈
Ca	ⓘ Apatite	Ca₅(PO₄)₃(Cl/F/OH)
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	ⓘ Hypersthene	(Mg,Fe)SiO₃
Fe	ⓘ Ilmenite	Fe²⁺TiO₃
Fe	ⓘ Native Iron	Fe
Fe	ⓘ Pigeonite	(Ca_xMg_yFe_z)(Mg_y1Fe_z1)Si₂O₆
Fe	ⓘ Troilite	FeS

Other Regions, Features and Areas containing this locality

North AmericaContinent

North America PlateTectonic Plate

Carolina TerraneVolcanic Arc
Carolinia DomainDomain

USA

⭔Southeastern United StatesArea

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References