The most common asteroidal igneous meteorites are eucrite-type basalts and gabbros rocks composed of ferroan pigeonite and augite, calcic plagioclase, silica, ilmenite, troilite, Ca-phosphate, chromite and Fe-metal. These rocks are thought to have formed on a single asteroid along with howardites and diogenites (HEDs). However, Northwest Africa (NWA) 011 is mineralogically identical to eucrites, but has an O-isotopic composition distinct from them and was derived from a different asteroid. Modern analyses with higher precision have shown that some eucrites have smaller O-isotopic differences that are nevertheless well-resolved from the group mean

Barrett, T.J.

Berger, E.L.

Greenwood, R.C.

Mittlefehldt, D.W.

Peng, Z.X.

Ross, D.K.

English

Berger, E. L.

Peng, Z. X.

Mittlefehldt, D. W.

Ross, D. K.

Barrett, T. J.

Greenwood, R. C.

NASA Technical Reports Server

PETROLOGIC AND OXYGEN-ISOTOPIC INVESTIGATIONS OF EUCRITIC AND ANOMALOUS 
MAFIC ACHONDRITES.  D. W. Mittlefehldt1, R. C. Greenwood2, Z. X. Peng3, D. K. Ross3,4, E. L. Berger5, and 
T. J. Barrett2, 1Astromaterials Research Office, NASA Johnson Space Center, Houston, TX, USA 
(david.w.mittlefehldt@nasa.gov), 2Dept. of Physical Sciences, The Open University, Milton Keynes, UK, 3Jacobs 
Technology, NASA Johnson Space Center, Houston TX, USA, 4UTEP-CASSMAR, 5GCS-Jacobs JETS-NASA 
Johnson Space Center, Houston, TX USA. 
 
 
Introduction:  The most common asteroidal igne-
ous meteorites are eucrite-type basalts and gabbros – 
rocks composed of ferroan pigeonite and augite, calcic 
plagioclase, silica, ilmenite, troilite, Ca-phosphate, 
chromite and Fe-metal [1]. These rocks are thought to 
have formed on a single asteroid along with howard-
ites and diogenites (HEDs). However, Northwest Afri-
ca (NWA) 011 is mineralogically identical to eucrites, 
but has an O-isotopic composition distinct from them 
and was derived from a different asteroid [2]. Modern 
analyses with higher precision have shown that some 
eucrites have smaller O-isotopic differences that are 
nevertheless well-resolved from the group mean [3-5]. 
Divalent Mn and Fe are homologous species that 
do not greatly fractionate during igneous processes. 
Distinct parent body FeO/MnO are caused by nebular 
fractionations that engender differences in Fe0/Fe2+, 
Fe3+/Fe2+, Fetotal/Mn and/or Fetotal/S. Because of this, 
mafic mineral Fe/Mn can be used to fingerprint parent 
object sources [6]. Oxygen-anomalous NWA 011 also 
has pyroxene Fe/Mn distinct from that of O-normal 
eucrites [2]. Ibitira, which displays a much smaller O-
isotopic anomaly [3, 4], has a resolvable difference in 
pyroxene Fe/Mn from normal eucrites [7]. 
We present the results of petrologic and O-isotopic 
studies of eucrites, and eucrite-type achondrites that 
are anomalous in O-isotopic composition and/or petro-
logic character (indicated here by blue font). Compan-
ion Cr isotopic studies on some of the meteorites dis-
cussed here are reported in [8]. 
Petrology:  Including previous work done at JSC, 
we discuss six cumulate gabbros; Allan Hills (ALH) 
85001, Elephant Moraine (EET) 87548, Moore County 
[9], Yamato (Y-) 791195 [10], Asuka (A-) 881394 and 
EET 92023, and 20 basalts; Bates Nunataks (BTN) 
00300, Dominion Range (DOM) 08001, EET 87520, 
EET 90020, Grosvenor Mountains (GRO) 06059, 
Larkman Nunatak (LAR) 06875, Miller Range (MIL) 
05041, MIL 07004, MIL 11290, Orlando, Sioux Coun-
ty, Stannern, Y-793164 (basalt clast) [10], Emmaville 
[11], EET 87542, Graves Nunataks (GRA) 98098, 
Ibitira [7], Pecora Escarpment (PCA) 82502, PCA 
91007 and Queen Alexandra Range (QUE) 94484. 
We focus on pyroxene compositions using their 
Fe/Mn to demonstrate differences. Eucrite-type mafic 
achondrites have been metamorphosed and their pi-
geonite contains augite exsolution lamellae [12]. We 
use only low-Ca pyroxenes for comparisons because 
Fe and Mn partition differently in pigeonite and augite. 
Cumulates and basalts are compared separately be-
cause pigeonite/melt partitioning results in a modest 
increase in pyroxene Fe/Mn during crystallization. 
Cumulate eucrites show the expected increase in 
Fe/Mn with Fe/Mg (Fig. 1a). A-881394 pyroxenes 
have slightly lower Fe/Mg but slightly higher Fe/Mn 
than that of EET 87548. The relative probability dis-
tributions for their pyroxene Fe/Mn overlap (Fig. 1b), 
but their means are different at the 99% confidence 
level; A-881394 is anomalous in Fe/Mn. EET 92023 
has pyroxene with Fe/Mg slightly higher than that of 
Moore County but much higher Fe/Mn (Figs. 1a, b); 
its pyroxene is anomalous with a mean Fe/Mn differ-
ent from that of Moore County at the 99% confidence 
level. This cumulate contains ~0.5 vol% Ni-rich metal 
[13, 14], an anomalous characteristic among eucrites. 
28
30
32
34
36
0.5 1.0 1.5 2.0
20
24
28
32
36
24 26 28 30 32 34 36
0.0
0.5
1.0
28 30 32 34 36 38
0.0
0.5
1.0
1.5
cores
 
 
 basaltic eucrites
 cumulate eucrites
 A-881394
 EET 92023
 Ibitira
Fe
/M
n 
(m
ol
ar
)
a
rims
 
 
 EET 87542
 Emmaville
 GRO 06059
 GRA 98098
 PCA 91007
 PCA 82502
 QUE 94484
Fe
/M
n 
(m
ol
ar
)
Fe/Mg (molar)
cores
c
re
la
tiv
e 
pr
ob
ab
ili
ty
 (%
)
low-Ca pyroxene Fe/Mn (molar)
 ALH 85001
 EET 87548
 Moore County
 Y-791195
 A-881394
 EET 92023
Fe/Mg = 0.51
0.84
1.02
1.35
0.81
1.03
b
re
la
tiv
e 
pr
ob
ab
ili
ty
 (%
)
low-Ca pyroxene Fe/Mn (molar)
 BTN 00300
 Ibitira
 Emmaville
 PCA 82502
 PCA 91007
 GRO 06059 (a)
 GRO 06059 (b)
d
 
Figure 1. Low-Ca pyroxene compositions for cumu-
lates (a, b) and basalts (c, d). 
Pyroxene compositions of O-anomalous metabasalt 
Emmaville cannot be distinguished from normal basal-
tic eucrites (Fig. 1c) [11]; its pyroxene Fe/Mn relative 
probability distribution overlaps those of normal eu-
crites (e.g., BTN 00300; Fig. 1d). PCA 82502 and 
PCA 91007 are identical, brecciated, vesicular, fine-
grained basalts containing pyroxenes with identical 
compositions that are resolvable from normal eucrites 
https://ntrs.nasa.gov/search.jsp?R=20160002386 2019-08-31T03:52:22+00:00Z
in Fe/Mn (Figs. 1c, d). Petrologically anomalous QUE 
94484 is an unbrecciated, unequilibrated basalt with 
astonishingly lower Fe/Mn in pyroxene rims compared 
to cores (Fig. 1c) [14, 15]. Core compositions mimic 
cumulate eucrite pyroxenes (Fig. 1a) and are consistent 
with early-crystallized pyroxene from a normal eucritic 
magma. EET 87542 is a brecciated, Fe-metal-rich bas-
alt with the lowest Fe/Mn among mafic achondrites 
(Fig. 1c). GRA 98098 is a metamorphosed basalt with 
cm-sized tridymite forming veins. It contains unusual-
ly Cl-rich Ca-phosphates [16], but has pyroxene com-
positions within the range of normal basaltic eucrites 
(Fig. 1c). GRO 06059 is a brecciated rock that con-
tains two populations of low-Ca pyroxene; most grains 
are normal in Fe/Mn but several isolated grain frag-
ments have Fe/Mn like that of Ibitira (Fig. 1 c, d). 
Oxygen Isotopic Compositions:  Oxygen isotope 
analyses have been done on EET 87520, EET 87542, 
EET 92023, GRA 98098, PCA 82502 and QUE 94484 
(Fig. 2). Our analysis of EET 92023 confirms its 
anomalous O-isotopic composition [17] with a Δ17O′ 
within ranges found for A-881394 [5] and Bunburra 
Rockhole [18]. PCA 82502 has a Δ17O′ just outside the 
3σ confidence limit on the HED mean used to identify 
O-anomalous mafic achondrites [19], and plots close 
to analyses of PCA 91007 with which it is paired on 
petrologic grounds. EET 87520, EET 87542, GRA 
98098 and QUE 94484 are isotopically normal. 
3.0 3.2 3.4 3.6 3.8 4.0 4.2
-0.2
-0.1
 diogenites
 cumulate eucrites
 basaltic eucrites
 EET 92023
 Pasamonte
 PCA 91007
 PCA 82502
 Ibitira
 EET 87520
 EET 87542
 GRA 98098
 QUE 94484
17
O
' (
‰
)
18O' (‰)
 HED mean ±3σ 
A-881394
Bunburra
Rockhole
 
Figure 2. O-isotope compositions of mafic achondrites, 
diogenites and eucrites; this study and [4, 5, 17-19]. 
Discussion:  The anomalous petrologic characteris-
tics of EET 87542 and QUE 94484 are caused by late-
stage reduction of FeO engendering the anomalous 
pyroxene Fe/Mn (Fig. 1c) [15, 20]. Their normal O-
isotopic compositions (Fig. 2) argue that this occurred 
on the HED parent asteroid. GRA 98098 has pyroxene 
Fe/Mn and O-isotope compositions indistinguishable 
from normal basaltic eucrites and we conclude that it, 
too, hails from the HED asteroid. (See [8] for Cr iso-
topic results.) PCA 82502 and PCA 91007 have cou-
pled O-isotopic and pyroxene-composition anomalies 
(Figs. 1d, 2). Their Δ17O′ are more than 3σ from the 
HED mean, and at the 99% confidence level, each of 
their mean pyroxene Fe/Mn are different from that of 
average normal basaltic eucrite. The paired PCA bas-
alts are unusual in containing vesicles, rare in basaltic 
eucrites, suggesting their magma contained higher 
volatile contents. These anomalous characteristics fa-
vor the hypothesis that they are derived from a differ-
ent asteroid, which might include Pasamonte (Fig. 2) 
[5]. Cumulate gabbros A-881394 and EET 92023 are 
distinguishable from cumulate eucrites in pyroxene 
Fe/Mn (Fig. 1) and vastly so in Δ17O′ (Fig. 2), suggest-
ing separate asteroids. A-881394 contains more calcic 
plagioclase than does EET 92023, An98 vs. An89-94, and 
the difference in their pyroxene Fe/Mn is greater than 
seems consistent with igneous fractionation (Fig. 1a). 
This suggests that these rocks are from two different 
asteroids. (See [8] for Cr isotopic results.) 
Our analyses of GRO 06059 indicate caution 
should be used in interpreting the petrologic data. The 
two pyroxene populations in it occupy both ends of the 
Fe/Mn range from normal basaltic eucrites to Ibitira 
(Fig. 1). GRO 06059 is a breccia containing different 
lithologic components, including impact-melt clasts; it 
might be a polymict eucrite. The high-Fe/Mn pyrox-
enes are grain fragments in the matrix; their parent 
lithology has yet to be identified. Continuing petro-
logic work on it will focus on understanding the origin 
of its pyroxene Fe/Mn populations. 
References: [1] Mittlefehldt D. W. (2015) Chem. 
Erde Geochem., 75, 155. [2] Yamaguchi A. et al. 
(2002) Science, 296, 334. [3] Wiechert U. H. et al. 
(2004) Earth Planet. Sci. Lett., 221, 373. 
[4] Greenwood R. C. et al. (2005) Nature, 435, 916. 
[5] Scott E. R. D. et al. (2009) Geochim. Cosmochim. 
Acta, 73, 5835. [6] Papike J. J. et al. (2003) Am. Min., 
8, 469. [7] Mittlefehldt D. W. (2005) Meteoritics & 
Planet. Sci., 40, 665. [8] Sanborn M. E. et al. (2016) 
LPS XLVII, this conference. [9] Mittlefehldt D. W. 
(1990) Geochim. Cosmochim. Acta, 54, 1165. 
[10] Mittlefehldt D. W. & Lindstrom M. M. (1993) 
Proc. NIPR Symp. Antarctic Meteorites, 6, 268. 
[11] Barrett T. J. et al. (2015) LPS XLVI, Abstract # 
2108. [12] Takeda H. & Graham A. L. (1991) Meteor-
itics, 26, 129. [13] Kaneda K. and Warren P. H. (1998) 
Meteoritics & Planet. Sci., 33, A81. [14] Mayne R. G. 
et al. (2009) Geochim. Cosmochim. Acta, 73, 794. 
[15] Mittlefehldt D. W. and Peng Z. X. (2015) Meteor-
itics & Planet. Sci., 50, Abstract #5342. [16] Sarafian 
A. R. et al. (2013) Meteoritics & Planet. Sci., 48, 
2135. [17] Greenwood R. C. et al. (2012) LPS XLIV, 
Abstract #3048. [18] Bland P. A. et al. (2009) Science, 
325, 1527. [19] Greenwood R. C. et al. (2014) Earth 
Planet. Sci. Lett., 390, 165. [20] Mittlefehldt D. W. et 
al. (2015) LPS XLVI, Abstract #1933. 


Petrologic and Oxygen-Isotopic Investigations of Eucritic and Anomalous Mafic Achondrites

Open Research Online (The Open University)

Open Research OnlineThe Open University’s repository of research publicationsand other research outputsPetrologic and oxygen-isotopic investigations of eucriticand anomalous mafic achondritesConference or Workshop ItemHow to cite:Mittlefehldt, D.W.; Greenwood, R.C.; Peng, Z.X.; Ross, D.K.; Berger, E.L. and Barrett, T.J. (2016). Petrologic andoxygen-isotopic investigations of eucritic and anomalous mafic achondrites. In: 47th Lunar and Planetary ScienceConference, 21-25 Mar 2016, Houston, Texas.For guidance on citations see FAQs.c© [not recorded]Version: Version of RecordCopyright and Moral Rights for the articles on this site are retained by the individual authors and/or other copyrightowners. For more information on Open Research Online’s data policy on reuse of materials please consult the policiespage.oro.open.ac.ukPETROLOGIC AND OXYGEN-ISOTOPIC INVESTIGATIONS OF EUCRITIC AND ANOMALOUS MAFIC ACHONDRITES.  D. W. Mittlefehldt1, R. C. Greenwood2, Z. X. Peng3, D. K. Ross3,4, E. L. Berger5, and T. J. Barrett2, 1Astromaterials Research Office, NASA Johnson Space Center, Houston, TX, USA (david.w.mittlefehldt@nasa.gov), 2Dept. of Physical Sciences, The Open University, Milton Keynes, UK, 3Jacobs Technology, NASA Johnson Space Center, Houston TX, USA, 4UTEP-CASSMAR, 5GCS-Jacobs JETS-NASA Johnson Space Center, Houston, TX USA.   Introduction:  The most common asteroidal igne-ous meteorites are eucrite-type basalts and gabbros – rocks composed of ferroan pigeonite and augite, calcic plagioclase, silica, ilmenite, troilite, Ca-phosphate, chromite and Fe-metal [1]. These rocks are thought to have formed on a single asteroid along with howard-ites and diogenites (HEDs). However, Northwest Afri-ca (NWA) 011 is mineralogically identical to eucrites, but has an O-isotopic composition distinct from them and was derived from a different asteroid [2]. Modern analyses with higher precision have shown that some eucrites have smaller O-isotopic differences that are nevertheless well-resolved from the group mean [3-5]. Divalent Mn and Fe are homologous species that do not greatly fractionate during igneous processes. Distinct parent body FeO/MnO are caused by nebular fractionations that engender differences in Fe0/Fe2+, Fe3+/Fe2+, Fetotal/Mn and/or Fetotal/S. Because of this, mafic mineral Fe/Mn can be used to fingerprint parent object sources [6]. Oxygen-anomalous NWA 011 also has pyroxene Fe/Mn distinct from that of O-normal eucrites [2]. Ibitira, which displays a much smaller O-isotopic anomaly [3, 4], has a resolvable difference in pyroxene Fe/Mn from normal eucrites [7]. We present the results of petrologic and O-isotopic studies of eucrites, and eucrite-type achondrites that are anomalous in O-isotopic composition and/or petro-logic character (indicated here by blue font). Compan-ion Cr isotopic studies on some of the meteorites dis-cussed here are reported in [8]. Petrology:  Including previous work done at JSC, we discuss six cumulate gabbros; Allan Hills (ALH) 85001, Elephant Moraine (EET) 87548, Moore County [9], Yamato (Y-) 791195 [10], Asuka (A-) 881394 and EET 92023, and 20 basalts; Bates Nunataks (BTN) 00300, Dominion Range (DOM) 08001, EET 87520, EET 90020, Grosvenor Mountains (GRO) 06059, Larkman Nunatak (LAR) 06875, Miller Range (MIL) 05041, MIL 07004, MIL 11290, Orlando, Sioux Coun-ty, Stannern, Y-793164 (basalt clast) [10], Emmaville [11], EET 87542, Graves Nunataks (GRA) 98098, Ibitira [7], Pecora Escarpment (PCA) 82502, PCA 91007 and Queen Alexandra Range (QUE) 94484. We focus on pyroxene compositions using their Fe/Mn to demonstrate differences. Eucrite-type mafic achondrites have been metamorphosed and their pi-geonite contains augite exsolution lamellae [12]. We use only low-Ca pyroxenes for comparisons because Fe and Mn partition differently in pigeonite and augite. Cumulates and basalts are compared separately be-cause pigeonite/melt partitioning results in a modest increase in pyroxene Fe/Mn during crystallization. Cumulate eucrites show the expected increase in Fe/Mn with Fe/Mg (Fig. 1a). A-881394 pyroxenes have slightly lower Fe/Mg but slightly higher Fe/Mn than that of EET 87548. The relative probability dis-tributions for their pyroxene Fe/Mn overlap (Fig. 1b), but their means are different at the 99% confidence level; A-881394 is anomalous in Fe/Mn. EET 92023 has pyroxene with Fe/Mg slightly higher than that of Moore County but much higher Fe/Mn (Figs. 1a, b); its pyroxene is anomalous with a mean Fe/Mn differ-ent from that of Moore County at the 99% confidence level. This cumulate contains ~0.5 vol% Ni-rich metal [13, 14], an anomalous characteristic among eucrites. 28303234360.5 1.0 1.5 2.0202428323624 26 28 30 32 34 360.00.51.028 30 32 34 36 380.00.51.01.5cores   basaltic eucrites cumulate eucrites A-881394 EET 92023 IbitiraFe/Mn (molar)arims   EET 87542 Emmaville GRO 06059 GRA 98098 PCA 91007 PCA 82502 QUE 94484Fe/Mn (molar)Fe/Mg (molar)corescrelative probability (%)low-Ca pyroxene Fe/Mn (molar) ALH 85001 EET 87548 Moore County Y-791195 A-881394 EET 92023Fe/Mg = 0.510.841.021.350.811.03brelative probability (%)low-Ca pyroxene Fe/Mn (molar) BTN 00300 Ibitira Emmaville PCA 82502 PCA 91007 GRO 06059 (a) GRO 06059 (b)d Figure 1. Low-Ca pyroxene compositions for cumu-lates (a, b) and basalts (c, d). Pyroxene compositions of O-anomalous metabasalt Emmaville cannot be distinguished from normal basal-tic eucrites (Fig. 1c) [11]; its pyroxene Fe/Mn relative probability distribution overlaps those of normal eu-crites (e.g., BTN 00300; Fig. 1d). PCA 82502 and PCA 91007 are identical, brecciated, vesicular, fine-grained basalts containing pyroxenes with identical compositions that are resolvable from normal eucrites 1240.pdf47th Lunar and Planetary Science Conference (2016)in Fe/Mn (Figs. 1c, d). Petrologically anomalous QUE 94484 is an unbrecciated, unequilibrated basalt with astonishingly lower Fe/Mn in pyroxene rims compared to cores (Fig. 1c) [14, 15]. Core compositions mimic cumulate eucrite pyroxenes (Fig. 1a) and are consistent with early-crystallized pyroxene from a normal eucritic magma. EET 87542 is a brecciated, Fe-metal-rich bas-alt with the lowest Fe/Mn among mafic achondrites (Fig. 1c). GRA 98098 is a metamorphosed basalt with cm-sized tridymite forming veins. It contains unusual-ly Cl-rich Ca-phosphates [16], but has pyroxene com-positions within the range of normal basaltic eucrites (Fig. 1c). GRO 06059 is a brecciated rock that con-tains two populations of low-Ca pyroxene; most grains are normal in Fe/Mn but several isolated grain frag-ments have Fe/Mn like that of Ibitira (Fig. 1 c, d). Oxygen Isotopic Compositions:  Oxygen isotope analyses have been done on EET 87520, EET 87542, EET 92023, GRA 98098, PCA 82502 and QUE 94484 (Fig. 2). Our analysis of EET 92023 confirms its anomalous O-isotopic composition [17] with a Δ17O′ within ranges found for A-881394 [5] and Bunburra Rockhole [18]. PCA 82502 has a Δ17O′ just outside the 3σ confidence limit on the HED mean used to identify O-anomalous mafic achondrites [19], and plots close to analyses of PCA 91007 with which it is paired on petrologic grounds. EET 87520, EET 87542, GRA 98098 and QUE 94484 are isotopically normal. 3.0 3.2 3.4 3.6 3.8 4.0 4.2-0.2-0.1 diogenites cumulate eucrites basaltic eucrites EET 92023 Pasamonte PCA 91007 PCA 82502 Ibitira EET 87520 EET 87542 GRA 98098 QUE 9448417O' (‰)18O' (‰) HED mean ±3σ A-881394BunburraRockhole Figure 2. O-isotope compositions of mafic achondrites, diogenites and eucrites; this study and [4, 5, 17-19]. Discussion:  The anomalous petrologic characteris-tics of EET 87542 and QUE 94484 are caused by late-stage reduction of FeO engendering the anomalous pyroxene Fe/Mn (Fig. 1c) [15, 20]. Their normal O-isotopic compositions (Fig. 2) argue that this occurred on the HED parent asteroid. GRA 98098 has pyroxene Fe/Mn and O-isotope compositions indistinguishable from normal basaltic eucrites and we conclude that it, too, hails from the HED asteroid. (See [8] for Cr iso-topic results.) PCA 82502 and PCA 91007 have cou-pled O-isotopic and pyroxene-composition anomalies (Figs. 1d, 2). Their Δ17O′ are more than 3σ from the HED mean, and at the 99% confidence level, each of their mean pyroxene Fe/Mn are different from that of average normal basaltic eucrite. The paired PCA bas-alts are unusual in containing vesicles, rare in basaltic eucrites, suggesting their magma contained higher volatile contents. These anomalous characteristics fa-vor the hypothesis that they are derived from a differ-ent asteroid, which might include Pasamonte (Fig. 2) [5]. Cumulate gabbros A-881394 and EET 92023 are distinguishable from cumulate eucrites in pyroxene Fe/Mn (Fig. 1) and vastly so in Δ17O′ (Fig. 2), suggest-ing separate asteroids. A-881394 contains more calcic plagioclase than does EET 92023, An98 vs. An89-94, and the difference in their pyroxene Fe/Mn is greater than seems consistent with igneous fractionation (Fig. 1a). This suggests that these rocks are from two different asteroids. (See [8] for Cr isotopic results.) Our analyses of GRO 06059 indicate caution should be used in interpreting the petrologic data. The two pyroxene populations in it occupy both ends of the Fe/Mn range from normal basaltic eucrites to Ibitira (Fig. 1). GRO 06059 is a breccia containing different lithologic components, including impact-melt clasts; it might be a polymict eucrite. The high-Fe/Mn pyrox-enes are grain fragments in the matrix; their parent lithology has yet to be identified. Continuing petro-logic work on it will focus on understanding the origin of its pyroxene Fe/Mn populations. References: [1] Mittlefehldt D. W. (2015) Chem. Erde Geochem., 75, 155. [2] Yamaguchi A. et al. (2002) Science, 296, 334. [3] Wiechert U. H. et al. (2004) Earth Planet. Sci. Lett., 221, 373. [4] Greenwood R. C. et al. (2005) Nature, 435, 916. [5] Scott E. R. D. et al. (2009) Geochim. Cosmochim. Acta, 73, 5835. [6] Papike J. J. et al. (2003) Am. Min., 8, 469. [7] Mittlefehldt D. W. (2005) Meteoritics & Planet. Sci., 40, 665. [8] Sanborn M. E. et al. (2016) LPS XLVII, this conference. [9] Mittlefehldt D. W. (1990) Geochim. Cosmochim. Acta, 54, 1165. [10] Mittlefehldt D. W. & Lindstrom M. M. (1993) Proc. NIPR Symp. Antarctic Meteorites, 6, 268. [11] Barrett T. J. et al. (2015) LPS XLVI, Abstract # 2108. [12] Takeda H. & Graham A. L. (1991) Meteor-itics, 26, 129. [13] Kaneda K. and Warren P. H. (1998) Meteoritics & Planet. Sci., 33, A81. [14] Mayne R. G. et al. (2009) Geochim. Cosmochim. Acta, 73, 794. [15] Mittlefehldt D. W. and Peng Z. X. (2015) Meteor-itics & Planet. Sci., 50, Abstract #5342. [16] Sarafian A. R. et al. (2013) Meteoritics & Planet. Sci., 48, 2135. [17] Greenwood R. C. et al. (2012) LPS XLIV, Abstract #3048. [18] Bland P. A. et al. (2009) Science, 325, 1527. [19] Greenwood R. C. et al. (2014) Earth Planet. Sci. Lett., 390, 165. [20] Mittlefehldt D. W. et al. (2015) LPS XLVI, Abstract #1933. 1240.pdf47th Lunar and Planetary Science Conference (2016)

Petrologic and oxygen-isotopic investigations of eucritic and anomalous mafic achondrites

Petrologic and oxygen-isotopic investigations of eucritic and anomalous mafic achondrites

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