1) NWA 7034 is a 319.8g martian meteorite found in Morocco in 2011. It is a porous basaltic breccia composed of feldspar and pyroxene phenocrysts in a fine-grained groundmass.
2) Chemical and isotopic analyses indicate it formed on Mars 2.089 billion years ago from a magma enriched in the martian crust. It contains over 6000ppm water, more than most martian meteorites.
3) NWA 7034 matches basalts analyzed at Gusev Crater by the Mars Exploration Rover and the average martian crust measured by orbiters, unlike other martian meteorites. Its composition suggests
Unique Meteorite from Early Amazonian Mars: Water-Rich Basaltic Breccia Northwest Africa 7034
1. Research Articles
Unique Meteorite from Early
(4.9 ± 1.3%), and apatite (3.7 ± 2.6%).
The x-ray data also indicate a minor
amount of iron-sulfide and chromite.
Amazonian Mars: Water-Rich Basaltic The data are also consistent with mag-
netite and maghemite making up ~70%
Breccia Northwest Africa 7034
and ~30%, respectively, of the iron
oxide detected (8).
Numerous clasts and textural varie-
1,2 1,2 1,2 1 ties are present in NWA 7034 that
Carl B. Agee, * Nicole V. Wilson, Francis M. McCubbin, Karen Ziegler, include gabbros, quenched melts, and
Victor J. Polyak,2 Zachary D. Sharp,2 Yemane Asmerom,2 Morgan H. Nunn,3 iron oxide-ilmenite-rich reaction
3 3 4 4
Robina Shaheen, Mark H. Thiemens, Andrew Steele, Marilyn L. Fogel, spherules (figs. S1 to S4) (8), however
4 4 3,5 1,2
Roxane Bowden, Mihaela Glamoclija, Zhisheng Zhang, Stephen M. Elardo the dominant textural type is a fine-
1 2
Institute of Meteoritics, University of New Mexico, Albuquerque, NM 87131, USA. Department of Earth grained basaltic porphyry with feldspar
3
and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131, USA. Department of and pyroxene phenocrysts. NWA 7034
4
Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA. Geophysical is a monomict brecciated porphyritic
5
Lab, Carnegie Institution of Washington, Washington, DC 20005, USA. School of Environmental Science basalt that is texturally unlike any SNC
and Engineering, Sun Yat-Sen University, Guangzhou 510275, China. meteorite. Basaltic breccias are com-
*To whom correspondence should be addressed. E-mail: agee@unm.edu mon in Apollo samples, lunar meteor-
Downloaded from www.sciencemag.org on January 3, 2013
ites, and HED meteorites, but wholly
We report data on the martian meteorite, Northwest Africa (NWA) 7034, which absent in the world’s collection of SNC
shares some petrologic and geochemical characteristics with known martian (SNC, meteorites (9). Absence of shocked-
i.e., Shergottite, Nakhlite, and Chassignite) meteorites, but also possesses some produced SNC breccias seems curious
unique characteristics that would exclude it from the current SNC grouping. NWA at face value, since nearly all of them
7034 is a geochemically enriched crustal rock compositionally similar to basalts and show evidence of being subjected to
average martian crust measured by recent rover and orbiter missions. It formed high shock pressures, with feldspar
2.089 ± 0.081 Ga, during the early Amazonian epoch in Mars’ geologic history. NWA commonly converted to maskelynite.
7034 has an order of magnitude more indigenous water than most SNC meteorites, Martian volcanic breccias are probably
with up to 6000 ppm extraterrestrial H2O released during stepped heating. It also has not rare given the observed widespread
bulk oxygen isotope values of Δ17O = 0.58 ± 0.05‰ and a heat-released water occurrence of volcanism on Mars.
oxygen isotope average value of Δ17O = 0.330 ± 0.011‰ suggesting the existence of However launch and delivery of such
multiple oxygen reservoirs on Mars. materials to Earth as meteorites has not
been observed (9). Although NWA
7034 is texturally heterogeneous both
The only tangible samples of the planet Mars that are available for study in hand sample and microscopically (Fig. 1), it can be considered a
in Earth-based laboratories, have up to now, been limited to the so-called monomict breccia because it shows a continuous range of feldspar and
SNC (1) meteorites and a single cumulate orthopyroxenite (Allan Hills pyroxene compositions that are consistent with a common petrologic
84001). The SNCs currently number 110 named stones and have provid- origin (figs. S5 and S6). We find no outlier minerals or compositions
ed a treasure trove for elucidating the geologic history of Mars (2). But that would indicate the existence of multiple lithologies or exotic com-
because of their unknown field context and geographic origin on Mars, ponents. We also see no evidence for polymict lithologies in either the
their fairly narrow range of igneous rock types and formation ages (3), it radiogenic or stable isotope ratios of NWA 7034 solids. However, many
is uncertain to what extent SNC meteorites sample the crustal diversity clasts and some of the fine-grained groundmass have phases that appear
of Mars. In fact, geochemical data from NASA’s orbiter and lander mis- to have been affected by secondary processes to form reaction zones. We
sions suggest that the SNC meteorites are a mismatch for much of the observed numerous reaction textures, some with a ferric oxide hydroxide
martian crust exposed at the surface (4). For example, the basalts ana- phase, which along with apatite, are the main hosts of the water in NWA
lyzed by the Mars Exploration Rover Spirit at Gusev Crater (5, 6) are 7034 (fig. S2). Impact processes are likely to have affected NWA 7034
distinctly different from SNC meteorites, and the Odyssey Orbiter gam- by virtue of the fact that this meteorite was launched off of Mars, ex-
ma ray spectrometer (7) (GRS) data show that the average martian crust ceeding the escape velocity – presumably by an impact–although the
composition does not closely resemble SNC. shock pressures did not produce maskelynite. One large (1-cm) quench
NWA 7034, on deposit at the Institute of Meteoritics, purchased by melt clast that was found could originate from shock processes (fig. S3).
Jay Piatek from Aziz Habibi, a Moroccan meteorite dealer, in 2011, is a On the other hand, the very fine groundmass with the large phenocrystic
319.8 g single stone, porphyritic basaltic monomict breccia, with a few feldspars and pyroxenes strongly suggests an eruptive volcanic origin for
euhedral phenocrysts up to several millimeters and many phenocryst NWA 7034, thus it is likely that volcanic processes are a source of the
fragments of dominant andesine, low-Ca pyroxene, pigeonite, and augite brecciation.
set in a very fine-grained, clastic to plumose, groundmass with abundant It has been shown (10) that Fe-Mn systematics of pyroxenes and
magnetite and maghemite; accessory sanidine, anorthoclase, Cl-rich olivines are an excellent diagnostic for classifying planetary basalts. Fe-
apatite, ilmenite, rutile, chromite, pyrite, a ferric oxide hydroxide phase, Mn of NWA 7034 pyroxenes, as determined by electron microprobe
and a calcium carbonate identified by electron microprobe analyses on analyses, most resemble the trend of the SNC meteorites from Mars (Fig.
eight different sections at the University of New Mexico (UNM). X-ray 2); other planetary pyroxenes such as in lunar samples and basalts from
diffraction analyses conducted at UNM on a powdered sample and on a Earth are poor matches for NWA 7034. Furthermore, feldspar composi-
polished surface show that plagioclase feldspar is the most abundant tions (fig. S5) (8) and compositions of other accessory phases in NWA
phase (38.0 ± 1.2%), followed by low-Ca pyroxene (25.4 ± 8.1%), 7034 are consistent with mineralogies commonly found in SNC meteor-
clinopyroxenes (18.2 ± 4.0%), iron-oxides (9.7 ± 1.3%), alkali feldspars ites (11), but not with any other known achondrite group. However, the
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2. average bulk chemical composition of NWA 7034 does not overlap in partial melting. Due to the instability of plagioclase at high pressure
major element space with SNC, instead it is remarkably similar to the (25), these processes would have necessarily occurred in the crust or
geochemistry of the rocks and soils at Gusev Crater and the average upper mantle of Mars. Consequently, the geochemically enriched source
martian crust composition from the Odyssey Orbiter gamma ray spec- that produced NWA 7034 could have originated from the martian crust
trometer (GRS) (Fig. 3 and figs. S7 and S8). NWA 7034, Gusev rocks, or mantle, much like the geochemically enriched reservoir(s) that are
and the GRS average martian crust all have higher concentrations of the recorded in the shergottites (26–30).
alkali elements sodium and potassium in comparison to SNC meteorites. Confocal Raman imaging spectroscopy (CRIS) conducted at the Ge-
Other major and minor element ratios such as Mg/Si, Al/Si, and Ni/Mg ophysical Laboratory, Carnegie Institution, in Washington DC (Carne-
have similarly good matches between NWA 7034 and Gusev Crater gie) identified the presence of macromolecular carbon (MMC) within
rocks (figs. S7 and S8). Although some experimental work has been mineral inclusions in the groundmass minerals of NWA 7034 (8). This
conducted to link martian meteorites to surface rocks analyzed by the MMC is spectrally similar to reduced organic macromolecular carbon
Mars Exploration Rovers (12–14), and aside from the exotic “Bounce that has been identified in several shergottites and a single nakhlite me-
Rock” (15) at Meridiani Planum, and hypothesized martian soil compo- teorite (fig. S15) (30), indicating that the production of organic carbon
nent in Tissint melt pockets (16), there has been no direct link between from abiogenic processes in the martian interior may not be unique to
the bulk chemical compositions of martian meteorites and surface rocks SNC-like source regions in Mars. Steele et al. (31) also demonstrated
to date. that the formation mechanism of MMC requires reducing magmatic
The rare earth element (REE) abundances of NWA 7034 were de- conditions consistent with oxygen fugacities below the fayalite-
termined by multi-collector inductively coupled plasma mass spectrome- magnetite-quartz (FMQ) buffer. Consequently, much of the ferric iron in
try (Neptune MC-ICP-MS) at UNM. They are significantly enriched the oxides of NWA 7034, as evidenced by EPMA and XRD analyses,
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relative to chondritric abundances with a marked negative europium was likely a product of oxidation subsequent to igneous activity as a
anomaly (Eu/Eu* = 0.67) (fig. S9 and table S2). The REE pattern has a result of secondary processes.
negative slope and light rare earth elements (LREE) are elevated relative Bulk carbon and carbon isotopic measurements on NWA 7034 were
to the heavy rare earth elements (HREE) (La/Yb)N = 2.3. Bulk SNC also carried out at Carnegie using combustion in an elemental analyzer
meteorites are much less enriched in REE (17) than NWA 7034 (fig. (Carlo Erba NC 2500) interfaced through a ConfloIII to a Delta V Plus
S10), although LREE enrichment relative to HREE and REE patterns isotope ratio mass spectrometer (ThermoFisher) in the same manner as
with negative slopes are seen in nakhlites, only magmatic inclusions and the data reported by (31, 32) (8). These data indicate that at least 22 ± 10
mesostasis in nakhlites and estimated nakhlite parent magmas have ppm carbon is present within mineral inclusions in NWA 7034, and the
LREE enrichments comparable to NWA 7034 (17, 18). We observed δ13C isotopic value of this carbon is –23.4 ± 0.73‰, which is very simi-
ubiquitous, relatively large (up to ~100 μm) Cl-rich apatite grains in lar to previous bulk C and δ13C analyses of carbon included in
NWA 7034 which presumably harbor a substantial fraction of the REEs shergottite meteorites analyzed in the same manner (31, 32). These data
in this meteorite, as merrillite/whitlockite was not identified in any of the indicate that multiple geochemical reservoirs in the martian interior may
investigated thin sections or probe mounts. have similarly light δ13C values. The bulk C concentration in the untreat-
A five-point isochron gives an Rb-Sr age for NWA 7034 of 2.089 ± ed sample performed in these measurements was 2080 ± 80 ppm C, with
0.081 Ga (2σ) (MSWD = 6.6), an initial 87Sr/86Sr ratio of 0.71359 ± 54 corresponding δ13C value of –3.0 ± 0.16‰. Scattered carbonate veinlets
(Fig. 4), and a calculated source 87Rb/86Sr ratio of 0.405 ± 0.028 (Fig. 5). from desert weathering were observed by BSE imaging and element
The Sm-Nd data for the same samples result in an isochron of 2.19 ± 1.4 mapping with the electron microprobe–especially in the near-surface
Ga (2σ). The high uncertainty in the latter is due to minimal separation material, but rarer in the deeper interior slices of NWA 7034. Although
between the data points generated from analysis of mineral separates. this carbonate is a minor phase within the meteorite, being below the
The small error on the Rb-Sr age may come from the abundance and detection of our XRD-analyses of the bulk sample, we believe this
variety of feldspar compositions in NWA 7034 (fig. S5). Furthermore, weathering product is sampled in our bulk carbon and carbonate anal-
we are confident that the Rb-Sr isochron and variations in the 87Sr/86Sr yses (8) (fig. S16).
values are the result of the time-integrated radiogenic growth from 87Rb Measurements of oxygen isotopic composition were performed by
and not the results of mixing between end-members with different laser fluorination at UNM on acid- and non-acid-washed bulk sample
87
Sr/86Sr values (figs. S11 to S14). The combined REE and isotopic data and at the University of California, San Diego (UCSD) on vacuum pre-
show that NWA 7034 is an enriched martian crustal rock (Fig. 5). The heated (1000°C) bulk sample (table S4). The triple oxygen isotope preci-
whole rock has 143Nd/144Nd = 0.511756 and 147Sm/144Nd = 0.1664, giv- sion on San Carlos olivine standard (δ18O = 5.2‰ vs. SMOW; Δ17O =
ing a calculated initial (source value) 143Nd/144Nd = 0.509467 ± 0‰) analyzed during sessions at UNM was Δ17O = ±0.03‰, precision at
0.000192 (initial εNd = –9.1 ± 1.7, calculated using the Rb-Sr age) which UCSD using NBS-28 quartz standard (δ18O = 9.62‰) was also Δ17O =
requires that it be derived from an enriched martian reservoir (19), with ±0.03‰. In total, twenty-one analyses of bulk NWA 7034 were carried
an inferred time-integrated 147Sm/144Nd = 0.1680 ± 0.0061, assuming out (Fig. 6). The mean value obtained at UNM was Δ17O = 0.58 ±
separation from a chondrite-like martian mantle at 4.513 Ga (18). Data 0.05‰ n = 13 for acid washed samples and Δ17O = 0.60 ± 0.02‰ n = 6
for each of our analyses is available in table S3. An age of ~2.1 Ga for for non-acid-washed samples; at UCSD the mean value was Δ17O = 0.50
NWA 7034 would make it the only dated meteorite sample from the ± 0.03‰ n = 2 for vacuum pre-heated samples that were dewatered and
early Amazonian (19) epoch in Mars’ geologic history. NWA 7034 is decarbonated. The combined data give Δ17O = 0.58 ± 0.05‰ n = 21.
derived from the most enriched martian source identified to-date; even These interlab values of bulk samples are in good agreement, but are
more enriched than the most enriched shergottites (20–23) (Fig. 5). significantly higher than literature values for SNC meteorites (Δ17O
Based on the REE enrichment, isotopic values, and match to rover ele- range 0.15-0.45‰) (33–36). Figure 6 shows that the δ18O values (5.5 to
mental data, NWA 7034 may better represent the composition of Mars’ 7.0‰ vs. SMOW) of NWA 7034 are higher than any determination from
crust than other martian meteorites. Although NWA 7034 may not be the SNC group. The Δ17O values of the non-acid-washed samples meas-
representative of a magmatic liquid, the negative europium anomaly and ured at UNM are similar to and within error of the acid-washed samples
absence of merrillite or whitlockite (24) is suggestive that the magma(s) indicating that NWA 7034 has, at most, only minor terrestrial weather-
parental to basaltic breccia NWA 7034 either underwent plagioclase ing products which would drive the non-acid-washed values closer to
fractionation prior to eruption or feldspar was left in the residuum during Δ17O = 0.00. The slope of the best-fit line to the combined UNM acid-
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3. washed and non-acid-washed data is 0.517 ± 0.025, suggesting that the the Δ17O of the bulk SNC samples. However, their observed Δ17O-
oxygen isotopic composition of NWA 7034 is the result of mass depend- relationship between bulk rock and water is reverse to the one seen in
ent fractionation processes. NWA 7034, with waters in general having more positive Δ17O values
There are no other known achondrites or planetary samples with than their respective host-rock (Nakhla, Chassigny, Lafayette). Only two
bulk oxygen isotope values similar to NWA 7034. Most achondrite shergottites (Shergotty, EETA-79001A) have waters with Δ17O values
groups have negative Δ17O values or near-zero values as do rocks from more negative than the host-rock, and Nakhla has water similar to its
the Earth and Moon. The oxygen isotope composition of Venus and host-rock. Romanek (43) analyzed iddingsite, an alteration product of
Mercury are currently unknown, but NWA 7034 is too oxidized and iron olivine and pyroxene, in Lafayette and found the Δ17O value is 1.37‰
rich to be derived from Mercury (37–39), and it seems to be a poor for a 90% iddingsite separate, supporting the positive Δ17O shift of Lafa-
match for Venus because it experienced low temperature alteration on its yette water relative to host-rock. Karlsson (41) argued that this Δ17O
parent body and has significant indigenous water, which would not per- difference suggested a lack of equilibrium between water and host rock
sist with the high surface temperatures on Venus (40). with the lithosphere and hydrosphere having distinct oxygen isotopic
The distinct δ18O and Δ17O values compared to other martian mete- reservoirs. Our data support this conclusion, but suggest that the Δ17O
orites can be explained by multiple reservoirs – either within the martian value of the ‘water’ reservoir is not always heavier than the rock reser-
lithosphere or between the lithosphere and a surficial component (41, 42) voir
– or by incorporation of exotic material. The idea of separate long-lived We determined the deuterium to hydrogen isotope ratio (δD value
silicate reservoirs is supported by radiogenic isotope studies (21, 23). vs. SMOW) and the water content of whole-rock NWA 7034 at UNM by
The distinct Δ17O and δ18O values of the silicate fraction of NWA 7034 both bulk combustion and stepped heating in a continuous flow, helium
compared to all SNC meteorites measured to date further supports the stream with high-T carbon reduction (49) (Fig. 8 and table S6). Six
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idea of distinct lithospheric reservoirs that have remained unmixed whole-rock combustion measurements yielded a bulk water content of
throughout martian history. A near-surface component with high Δ17O 6190 ± 620 ppm. The mean δD value for the bulk combustion analyses
values has been proposed on the basis of analysis of low temperature was +46.3 ± 8.6‰. The maximum δD values in two separate stepwise
alteration products (41–43), and this may, in part, explain the Δ17O dif- heating experiments were +319‰ and +327‰, reached at 804°C and
ferences between the bulk and ‘water-derived’ components of NWA 1014°C respectively (table S6), similar to values seen in the nakhlites
7034. However, the Δ17O value of 0.58‰ for the bulk silicate is different (50). Figure 8 shows that most of the water in NWA 7034 is released
from the Δ17O value of 0.3‰ found in all SNC samples measured to between approximately 150-500°C, and that there are two plateaus of δD
date. If materials with a non 0.3‰ Δ17O value are attributed to a surficial values, one around –100‰ at 50-200°C and a second around +300‰ at
(atmospheric) component, then the bulk of NWA 7034 would have nec- 300-1000°C. This suggests that there are two distinct δD components in
essarily undergone extensive exchange with this reservoir. This is a pos- NWA 7034, a low temperature negative value component and a high
sibility, given the abundance of low-temperature iron oxides. The temperature positive value component. One possibility is that the low
ramifications of distinct lithospheric reservoirs are very different from temperature negative values are from terrestrial water contamination,
those attributed to a different surficial reservoir. The latter could be ex- although the Δ17O values in water released at even the lowest tempera-
plained by photochemical-induced isotope fractionation and/or hydrody- ture step of 50°C has a 0.3‰ anomaly (Fig. 7). It is also possible that
namic escape (44–46), while the former is consistent with a lack of protium-rich water is released at the lowest steps of dehydration, alt-
initial planet-wide homogenization and an absence of plate tectonics hough such fractionation is not observed on terrestrial samples. Alterna-
(41). Isolated lithospheric oxygen isotope reservoirs are inconsistent tively, the hydrogen, but not oxygen isotope ratios could have been
with a global magma ocean scenario for early Mars, which would have affected by terrestrial alteration. Finally, it is possible that nearly all the
very efficiently homogenized oxygen isotopes in the planet as occurred released water from NWA 7034 is in fact martian and not terrestrial. In
for the Earth and Moon. Instead, Mars’ differentiation could have been this case, the hydrogen isotope ratios have fractionated as a function of
dominated by basin forming impacts that left regional or even hemi- temperature, or there are two distinct hydrogen isotope reservoirs.
sphere scale magmatic complexes (47, 48) with distinct and varied iso- Our data show that NWA 7034 has more than an order of magnitude
topic and geochemical characteristics. more indigenous water than most SNC meteorites. The amount of water
Another possibility is that NWA 7034 originally had oxygen isotope released at high temperature (>320°C) is 3280 ± 720 ppm. Leshin et al.
values similar to or the same as SNC, but a cometary component with (50) measured an average of 249 ± 129 ppm H2O released above 300-
higher δ18O δ17O, and Δ17O was mixed with it through impact processes 350°C in seven bulk SNC meteorites, with exception of the anomalous
on Mars, thus producing a Δ17O excess relative to SNC. Until we find Lafayette nakhlite which released 1300 ppm H2O above 300°C. They
clear evidence of such an exotic component in NWA 7034, this scenario (50) argued that some of the water released at temperatures as low as
seems less likely than the other two. 250°C could in fact be from martian alteration products. Given our oxy-
The oxygen isotope ratio of water released by stepped heating in a gen water analyses this could also be the case for NWA 7034 at tempera-
vacuum at UCSD (table S5) show that most, if not all, of the water in tures as low as 50°C. Hence the total amount of martian water in NWA
NWA 7034 is extraterrestrial with Δ17O values well above the terrestrial 7034 could be in the vicinity of 6000 ppm, possibly supporting hypothe-
fractionation line (Fig. 7). NWA 7034 water falls primarily within the ses that aqueous alteration of near surface materials on Mars occurred
range of values for bulk SNC meteorites with a weighted mean value of during the early Amazonian Epoch 2.1 billion years ago either by
Δ17O = +0.33 ± 0.01‰, with δ18O and δ17O values giving a slope of magmatically derived or meteoric aqueous fluids (51–53).
0.52, indicating mass dependent fractionation. Interestingly, the Δ17O The young 2.1 Ga crystallization age of NWA 7034 requires that it is
value for NWA 7034 water is lower than, and outside the range of, the planetary in origin. Its major, minor, trace, and isotopic chemistry is
Δ17O for bulk NWA 7034, offering clear evidence that there are multiple inconsistent with originating from Earth, Moon, Venus, or Mercury, and
distinct oxygen isotope sources for this sample. The Δ17O value of the it is most similar to rocks from Mars. Yet still, NWA 7034 is unique
water released at the 500-1000°C range (+0.09‰) is approaching terres- from any other martian meteorites, as it is the most geochemically en-
trial values, and this could be from decomposition of the terrestrial car- riched rock from Mars that has been found to date. Moreover, the bulk
bonate veins in the meteorite and equilibration of the produced CO2 with chemistry of NWA 7034 is strikingly similar to recently collected orbital
the released water. Karlsson et al. (41) reported oxygen isotope values of and lander data collected at the martian surface, allowing for a direct link
water from several SNC meteorites and also saw that they differed from between a martian meteorite and orbital and lander spacecraft data from
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higher bulk δ18O and Δ17O, suggesting the existence of multiple oxygen on Martian differentiation processes from Rb-Sr and Sm-Nd isotopic analyses
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Acknowledgments: We acknowledge Jay Piatek, MD for acquiring the NWA
7034 specimen and for his generous donation to the UNM Meteorite Museum,
which has enabled this research and sample allocations for future research on
NWA 7034. We also acknowledge M. Spilde, V. Atudorei, and J. Connolly at
the University of New Mexico for assistance with data collection. CA, NW,
and FM acknowledge support from NASA’s Cosmochemistry Program
(NNX11AH16G to CA and NNX11AG76G to FM). SE acknowledges
support from the New Mexico Space Grant Consortium, NASA Earth and
Space Science Fellowship NNX12AO15H, and NASA Cosmochemistry grant
NNX10AI77G to Charles K. Shearer. MT and RS acknowledge NSF award
(ATM0960594) that allowed the development of analytical technique to
measure oxygen triple isotopic composition of small (< 1 micro mole) sulfate
samples.
Supplementary Materials
www.sciencemag.org/cgi/content/full/science.1228858/DC1
Materials and Methods
Figs. S1 to S16
Tables S1 to S6
References (57–71)
15 August 2012; accepted 14 December 2012
Published online 3 January 2013
10.1126/science.1228858
/ http://www.sciencemag.org/content/early/recent / 3 January 2013 / Page 5/ 10.1126/science.1228858
6. Fig. 1. (A) NWA 7034 hand specimen. (B)
Backscatter electron image of porphyritic
texture in NWA 7034. Large dark crystals are
feldspar, large light colored crystals are
pyroxene.. Portion of a gabbroic clast is
shown above the scale bar.
Downloaded from www.sciencemag.org on January 3, 2013
Fig. 2. Fe versus Mn (atomic formula units) showing the
trend for all NWA 7034 pyroxenes (cyan dots, 349
microprobe analyses) and for comparison pyroxene trends
from Mars (red), Moon (green), and Earth (blue) (10).
/ http://www.sciencemag.org/content/early/recent / 3 January 2013 / Page 6/ 10.1126/science.1228858
7. Fig. 3. Volcanic rock classification scheme
based on the abundance of alkali elements
and SiO2, modified after McSween et al. (4).
Red dots are analyses from Alpha-Proton-X-
ray Spectrometer (APXS) of rocks and soils
from the Spirit Rover at Gusev Crater (5, 6).
Yellow rectangle is the average martian
crust as measured by the Gamma Ray
Spectrometer (GRS) on the Mars Odyssey
Orbiter (7). The pink field is the known range
of martian meteorite (SNC) compositions.
The cyan dot is the mean value of bulk NWA
7034 as determined by 225 electron
microprobe analyses of fine-grained
groundmass with error bars giving one
standard deviation.
Downloaded from www.sciencemag.org on January 3, 2013
Fig. 4. Rb-Sr whole-rock-mineral
isochron of NWA 7034. The mineral
fractions are labeled as Light -1, Drk-1,
2, 3 based on abundance of dark
magnetic minerals. Light-1, with high
87
Rb/86Sr was the least magnetic
fraction. An MSWD value of 6.6
suggests the small scatter in the values
cannot be explained by analytical errors
and may include slight isotopic
heterogeneities in the rock. 2σ
measurement errors were used for the
87
Sr/86Sr data and 2% errors for the
87
Rb/86Sr data were used for age
calculation. Larger errors were assigned
87 86
to the Rb/ Sr ratios because of the
inability to do internal mass fraction on
Rb isotopic measurements (Rb only has
two isotopes). There was not enough
Sm and Nd in the mineral fractions to
provide a meaningful age.
/ http://www.sciencemag.org/content/early/recent / 3 January 2013 / Page 7/ 10.1126/science.1228858
8. Downloaded from www.sciencemag.org on January 3, 2013
Fig. 5. (A) Plot of bulk rock La/Yb ratio vs. εNd calculated at 175 Ma for NWA 7034 and basaltic Shergottites. Solid line
represents two-component mixing line between NWA 7034 and QUE 94201. (B) Plot of calculated parent/daughter source
ratios for NWA 7034, basaltic Shergottites, Nakhlites and Chassigny (Nak/Chas), and lunar mantle sources. Solid line
represents two-component mixing line between depleted lunar mafic cumulates and lunar KREEP. Depleted lunar mafic
cumulates are estimated by (54–56). Lunar KREEP is estimated by (56). Data for basaltic Shergottites, Nakhlites and
Chassigny are from (22, 23) and references therein.
Fig. 6. Oxygen isotope plot showing the values of NWA 7034 Fig. 7. Δ17O versus temperature diagram showing the values
from this study, units are per mil. Cyan dots, 13 analyses of for NWA 7034 water released by stepped heating. Vertical
bulk acid-washed and 6 analyses of bulk non-acid-washed error bars are given for each data point, horizontal line
(UNM), cyan squares, 2 analyses of dry, de-carbonated bulk, segments show the temperature range for each step, and the
preheated to 1000°C (UCSD). Red dots are SNC meteorites thickness of the line segment indicates the relative proportion
from the literature (33–36, 41). TFL = terrestrial fractionation of water released at each step. Dashed line is the mean
17
line, slope 0.528. value of Δ O for NWA 7034 water. Also shown are ranges of
17
Δ O for bulk NWA 7034 analyses and for bulk SNC values
from the literature. TFL = terrestrial fractionation line.
/ http://www.sciencemag.org/content/early/recent / 3 January 2013 / Page 8/ 10.1126/science.1228858
9. Fig. 8. δD versus temperature diagrams showing the data for Downloaded from www.sciencemag.org on January 3, 2013
NWA 7034 bulk sample done by stepped heating. The
horizontal solid lines represent the temperature intervals, the
circle are the mid-interval temperature. The two plots
represent two aliquots of NWA 7034 sample.
/ http://www.sciencemag.org/content/early/recent / 3 January 2013 / Page 9/ 10.1126/science.1228858
10. www.sciencemag.org/cgi/content/full/science.1228858/DC1
Supplementary Materials for
Unique Meteorite from Early Amazonian Mars: Water-Rich Basaltic Breccia
Northwest Africa 7034
Carl B. Agee,* Nicole V. Wilson, Francis M. McCubbin, Karen Ziegler, Victor J. Polyak,
Zachary D. Sharp, Yemane Asmerom, Morgan H. Nunn, Robina Shaheen, Mark H. Thiemens,
Andrew Steele, Marilyn L. Fogel, Roxane Bowden, Mihaela Glamoclija, Zhisheng Zhang,
Stephen M. Elardo
*To whom correspondence should be addressed. E-mail: agee@unm.edu
Published 3 January 2013 on Science Express
DOI: 10.1126/science.1228858
This PDF file includes:
Materials and Methods
Figs. S1 to S16
Tables S1 to S6
References
11. Methods
Electron microprobe (UNM)
Electron microprobe analyses and back-scattered electron images were performed
using a JEOL 8200 Electron Probe Microanalyzer, equipped with five wavelength
dispersive spectrometers. Quantitative analyses were carried out on two thin sections and
three probe mounts of NWA 7034 taken from different locations in the stone. Analyses
were made using a tungsten filament electron gun at 15 kV accelerating voltage and
20nA beam current. Most analyses were collected with 1µm-diameter beam, but feldspar
analyses were collected using a 10-20µm-diameter beam, and plumose groundmass (bulk
composition) was analyzed with a 20µm-diameter beam.
X-ray powder diffraction (UNM)
One aliquot of NWA 7034 powder and one thick polished section were analyzed by
X-ray diffraction (XRD) in the XRD Laboratory in the Department of Earth and
Planetary Sciences at the University of New Mexico, using a Rigaku SmartLab
diffractometer system with the SmartLab Guidance system control software for system
automation and data collection. Cu-K-alpha radiation (40 kV, 40 mA) was used with a
D/teX Ultra High Speed Silicon Strip Linear (1D) detector. The powdered sample was
prepared in a thick deep powder mount and analyzed at 40 kV and 25 mA using a
continuous scanning procedure with a n effective step size of 0.02 degrees at a scan rate
of °2θ/min over the range 5–90 °2θ with incident slits set to 0.5 deg, and both receiving
slits set to the maximum (20 mm). JADE® (MDI, Pleasanton, CA) analysis software was
used to determine modal abundances of the major minerals present. Peak intensity
variations were in general accord with qualitative estimates of modal abundance by
petrography, so we attempted to quantify the modal abundances of minerals in NWA
7034 using the Rietveld refinement tool in the JADE® (MDI, Pleasanton, CA) analysis
software. The variation in mineral mode between the two XRD analyses is likely a result
of the heterogeneous nature of the NWA 7034 breccia.
REE analyses and Sr, Rb, Nd, and Sm isotopes (UNM)
REE measurements of NWA-7034 and basalt standard BHVO-2 were made on
the Thermo X-Series II inductively coupled plasma mass spectrometer (ICPMS). A
whole rock powder was leached with 1M acetic acid for 10 minutes, and then dissolved
in an acid consisting of 20% concentrated nitric acid and 80% HF in Teflon bombs at
120°C for 48 hours. The solution was transferred to a Teflon beaker and dried down. It
was redissolved in 6M HCl and dried again, then dissolved in 0.5 ml of 7M nitric acid,
then diluted in 3% nitric acid containing two internal standards (In and Re). The solution
was analyzed against standard BHVO-2. Results are listed in Table S2 relative to values
reported for BHVO-2 [57-58].
Subsamples of NWA-7034 were separated using a magnet. The fine-grained
nature of the sample and the high concentration of magnetite made separation of minerals
difficult. The subsample powders were leached with 1M acetic acid for 10 minutes, and
then dissolved in an acid consisting of 20% concentrated nitric acid and 80% HF in
Teflon bombs at 120°C for 48 hours. The leachates were collected. The five separates
consisted of the whole-rock aliquot, a light mineral fraction that could consist of feldspars
2
12. and Cl-apatite, and three dark Fe-rich mineral fractions. The subsample powders were
leached with 1M acetic acid for 10 minutes, and then dissolved in an acid consisting of
20% concentrated nitric acid and 80% HF in Teflon bombs at 120°C for 48 hours. Each
dissolved subsample was transferred to Teflon beakers and spiked with a mixed 84Sr-87Rb
spike and a 146Nd-149Sm spike, and 2 drops of perchloric acid were added. Samples were
fluxed and then lightly dried down and redissolved in 6M HCl with 10 drops of boric
acid. After another light dry down, the subsamples were dissolved in 2M HCl and dried
softly, and redissolved in 1M nitric acid for column chemistry. Subsamples were passed
through Tru-spec resin to collect the REE fraction, and then through Sr-spec resin to
collect the Sr fraction. The waste included the Rb fraction and was collected for Rb
column chemistry. The Sr fraction was passed through the Sr-spec resin again. Two
column chemistry procedures were modified for Rb separation. The methods used are
after [59-60]. [59] processed microsamples and used AG50 WX8 (50-100 mesh) cation
resin to separate Rb. [60] passed the Rb fraction through AG50W-X12 (200-400 mesh) to
separate the Rb. Both methods produced the same results. The REE fraction was passed
through Ln-spec cation resin to separate both Nd and Sm after the methods of [61]. Two
subsamples of basalt standard BHVO-2 were processed through the Sr-Rb column
chemistry with the NWA-7034 subsamples.
Subsample Rb, Sr, Nd, and Sm separates were analyzed on a Thermo Neptune
multi-collector inductively coupled plasma mass spectrometer (MC-ICPMS), and these
included three leachates. Results are listed in Tables S1 and S2. Concentrations of Rb
and Sr for standard BHVO-2 were 9.7 and 9.8 ug/g Rb and 398.2 and 397.9 ug/g. [62]
reported 9.6 and 381 ug/g for Rb and Sr, respectively, and the USGS certify this standard
as 9.8±1 and 389±23 ug/g, respectively [57]. Our 87Sr/86Sr value for BHVO-2 is
0.70347, which is identical to that reported by [62], and relative to a 87Sr/86Sr value of
0.71025 for NBS 987. We measured the 87Rb/85Rb for a SPEX brand ICP standard to be
0.38567 normalized to 91Zr/90Zr [after 59], a value within error of the reported terrestrial
value of 0.38570 ± 0.00060 by the IUPAC [60], and that measured by [63] of 0.38554 ±
0.00030, which was normalized to 92Zr/90Zr. Recently, the calculated 87Rb/85Rb values
based on normalization to a Sr double-spike are higher than those normalized to 92Zr/90Zr
or 91Zr/90Zr by about 0.2% (0.386353 ± 0.000004; [64]). These value differences are
insignificant with respect to the errors on our Rb-Sr isochron age. Rb and Sr results from
the three leachates that were passed through the columns fall on the isochron. Isochron
ages were constructed with ISOPLOT [65].
Elemental and isotopic analysis of carbon (Carnegie)
The chemical (ppm C) and isotopic composition (δ13C relative to V-SMOW) of
carbon in meteorite samples was determined by combustion in an elemental analyzer
(Carlo Erba NC 2500) interfaced through a ConfloIII to a Delta V Plus isotope ratio mass
spectrometer (ThermoFisher). Carbon concentrations were calculated using a calibration
derived from measuring a homogenous sediment sample (Peru Mud, Penn State
University) containing 6.67% C (by weight). For this study, 10-100 mg of this standard
was weighed out, which corresponds to 0.6 to 6 mg C. The δ13C of Peru Mud was -
19.92±0.32 ‰ (n=40) for samples in this size range. Rock powders were weighed into
4x6mm Ag capsules that were pre-combusted at 599°C in air for 2 to 4 h to remove
organic carbon contamination. Blanks from capsules were 0.2±0.07 mg (n=72). Details
3
13. for this were published in [29, 66]. This same protocol was followed for the NWA 7034
sample presented in this study. In general, 5-10 mg of powdered meteorite matrix was
weighed for concentration and isotopic measurements. This meteorite contained
measurable nitrogen concentrations, which is unusual for other Martian meteorite
samples measured [31]. Therefore, in this study, we report values for NWA 7034 that
were prepared in pre-combusted Ag boats. Samples were acidified within the boats and
soluble compounds were not washed away. Second, we acidified samples in Ag boats,
then combusted the boat plus sample at 599 °C for 2 hours. Measurements are presented
without blank correction for isotopic composition, because blanks were below normal
detection limits with the Carlo Erba-Delta V system.
The bulk C concentration in the untreated sample was 2080 ± 80 ppm C, with
corresponding δ13C value of -3.0 ± 0.16‰. Subsequent to acid washing, the bulk C
concentration dropped to 310 ± 10 ppm, with a corresponding δ13C value of -21.6 ±
0.14‰, indicating substantial carbonate in NWA 7034, which was also confirmed by
optical microscopy and back scattered electron microscopy at UNM, and by isotopic
analyses of inorganic carbonate at UCSD . The acid-washed and muffled sample yielded
22 ± 10 ppm C, with an isotopic value of -23.4 ± 0.73‰, which is very similar to
previous bulk C and δ13C analyses of shergottite meteorites after acid-washing and
muffling [31-32].
Raman analysis (Carnegie)
Raman spectra and images were collected using a Witec α-Scanning Near-Field
Optical Microscope that has been customized to incorporate confocal Raman
spectroscopic imaging. The excitation source is a frequency-doubled solid-state YAG
laser (532nm) operating between 0.3 and 1 mW output power (dependent on objective),
as measured at the sample using a laser power meter. Objective lenses used included a
x100 LWD and a x20 LWD with a 50µm optical fiber acting as the confocal pin hole.
Spectra were collected on a Peltier-cooled Andor EMCCD chip, after passing through a
f/4 300mm focal length imaging spectrometer typically using a 600 lines/mm grating.
The lateral resolution of the instrument is as small as 360 nm in air when using the x100
LWD objective, with a focal plane depth of ~800nm. This instrument is capable of
operating in several modes. Typically 2D imaging and single spectra modes were used
during this study. Single spectra mode allows the acquisition of a spectrum from a single
spot on the target. Average spectra are produced typically using integration times of 30
seconds per accumulation and 10 accumulations to allow verification of weak spectral
features. Further details on the Raman instrument used can be found in [31, 67-68]. We
used both transmitted and reflected light microscopy to locate the field of interest. Target
areas were identified on the thin section in transmitted light. The microscope was then
switched to reflected light and refocused to the surface. At which point X, Y and Z piezos
of the stage were reset. Switching back to transmitted light then allows an accurate
measurement of the depth of the feature of interest. The height and width of the field of
interest within the light microscopy image were then measured and divided by the lateral
resolution of the lens being used, to give the number of pixels per line. The instrument
then takes a Raman spectrum (0-3600 cm-1 using the 600 lines mm-1 grating) at each pixel
using an integration time of between 1 and 6 s per pixel. A cosmic ray reduction routine
was used to reduce the effects of stray radiation on Raman images, as was image
4
14. thresholding to reject isolated bright pixels. Fluorescence effects were inhibited by the
use of specific peak fitting in place of spectral area sums and by the confocal optics used
in this instrument. The effects of interfering peaks were removed by phase masking
routines based on multiple peak fits as compared to standardized mineral spectra. This
produces an average spectrum over the number of pixels chosen in the area of interest.
Standard spectra were obtained from an internal Raman database provided by the RRUFF
project (www.rruff.info).
Isotopic analysis of inorganic carbonates and sulfates (UCSD)
These analyses were performed by acid extraction, gas chromatography, fluorination and
isotope ratio mass spectrometry. One gram of NWA7034 was ground to fine powder,
evacuated to 10-6Torr with 100% phosphoric acid in reaction vessel. CO2 released upon
acid digestion at 25 ± 1 oC was collected after 1, 2 and 12 hours in three successive steps.
The mixture was heated at 150 oC for three hours to release CO2 from non calcium or Fe-
Mn-Mg rich carbonate fractions. The step-wise CO2 extraction procedure was adopted to
isolate terrestrial contamination from the Martian meteorite. C and O-triple isotopic
composition of carbonates was measured following the method developed by Shaheen et
al. [69]. Inorganic sulfate was extracted by dissolving 1 g of NWA7034 in 2 mL of
Millipore water, sonicated for 3hours and supernatant collected in a vial. The step was
repeated twice to ensure complete removal of water soluble ions. Organic impurities were
removed from the supernatant by treating with 30% H2O2 (1.0 mL) and further passing
through polyvinyl pyrolydine (PVP), C18 (Alltech) resins. SO4 was separated from other
anions using liquid chromatography, converted to silver sulfate and pyrolyzed at 1050 oC
for oxygen isotope analysis.
The carbonate and sulfate weathering products that were sampled in oxygen triple
isotope analyses of carbonate and sulfate done by step-wise acid dissolution at UCSD
yielded values of Δ17O=-0.04±0.04‰ n=4 and Δ17O=+0.04‰ n=1, respectively, with a
bulk CO3=0.87 wt% (Fig, S16). O-triple isotope analysis of carbonate minerals (δ17O =
19-24‰ δ18O = 37- 46‰) showed higher O-isotope enrichment compared to the desert
dust samples (δ17O = 15-21‰ δ18O = 29-41‰). However, NWA7034 carbonates and
desert soil samples possess Δ17O~0. Oxygen triple isotope analysis of water soluble
sulfate (δ17O = 3.7‰ δ18O= 6.7‰) showed mass dependently fractionated oxygen
reservoirs. The Δ17O ~ 0 of secondary minerals (carbonates and sulfates) indicates their
precipitation from a water reservoir with no oxygen isotope anomaly suggesting either
terrestrial origin or subaerial martian water reservoir not in contact with the martian
atmosphere and decoupled from the other oxygen carrying reservoirs. The Carnegie
measurements show that there is significant organic carbon from both indigenous and
exogenous terrestrial sources. Both Carnegie and UCSD detected terrestrial carbonate
component in their bulk samples although they have significantly different values in the
total measured carbon and the bulk value of δ13C. We attribute these differences to
heterogeneous distribution of carbonate in NWA 7034, with a heterogeneous input of
organic material to the isotope values.
Sample Treatment % CO3 δ13C δ17O δ18O Δ17O
(‰) (‰) (‰) (‰)
NWA7034 1st h at 25o C 0.54 0.87 24.00 46.49 0.013
NWA7034 2nd h at 25o C 0.06 0.75 23.62 45.89 -0.05
NWA7034 12 h at 25o C 0.2 0.56 23.72 46.09 -0.05
5
15. NWA7034 3 h at 150o C 0.07 0.17 19.23 37.43 -0.07
Arizona Test Dust 12 h at 25o C 4.96 -8.97 15.10 29.48 -0.10
Owen Lake Dust 12 h at 25o C 5.08 -3.64 18.21 35.60 -0.15
Black Rock Desert Dust, 12 h at 25o C 7.03 -6.069 18.04 35.25 -0.15
Nevada
YaDan GanSu dust, China 12 h at 25o C 7.38 -13.52 16.51 32.24 -0.12
Grand Canyon Red Soil 12h at 25o C 0.05 -16.68 20.98 41.07 -0.21
Commercial cement sample 12 h at 25o C 4.99 -19.34 14.38 28.06 -0.09
*NWA7034- SO4 3.52 6.74 0.04
Overall uncertainty of the procedure is δ13C = 0.1‰, δ17O and δ17O =0.3‰, Δ17O=0.1‰.
The precision of the isotopic ratio measurements are +0.03‰. Carbon and oxygen isotope
values are reported with reference to V-PDB and SMOW.
* 1 µmole of sulfate was obtained by dissolving 1g powdered meteorite in Millipore
water and sonicating for 3 hours. The procedure was repeated three times to ensure
complete removal of water soluble sulfates.
Oxygen isotopes (UNM)
Oxygen isotope analyses of NWA 7034 were performed by laser fluorination at UNM
on acid-washed bulk samples (removal of possible terrestrial weathering products).
Pretreated samples (1-2 mg) were pre-fluorinated (BrF5) in the vacuum chamber in order
to clean the stainless steel system and to react residual traces of water or air in the
fluorination chamber. Molecular oxygen was released from the samples by the laser-
assisted fluorination (25W far-infrared CO2 laser) in a BrF5-atmoshpere, producing
molecular O2 and solid fluorides. Excess BrF5 was then removed from the produced O2
by reaction with hot NaCl. The oxygen was purified by freezing to a 13Å molecular sieve
at -196°C, followed by elution of the O2 from the first sieve at −131°C to a second 5Å
molecular sieve at −190°C [70]. Measurements of the isotope ratios were then made on a
Finnigan DeltaXLPlus dual inlet isotope ratio mass spectrometer, and the oxygen isotope
ratios were calibrated against the isotopic composition of San Carlos olivine. Each
sample gas was analyzed multiple times, and each analysis consisted of 20 cycles of
sample-standard comparison. Olivine standards (~1-2 mg) were analyzed daily. Oxygen
isotopic ratios were calculated using the following procedure: The δ18O values refer to
the per-mil deviation in a sample (18O/16O) from SMOW, expressed as δ18O =
[(18O/16O)sample/(18O/16O)SMOW-1] × 103. The delta-values were converted to linearized
values by calculating: δ18/17O’ = ln[(δ 18/17O + 103)/103] × 103 in order to create straight-
line mass-fractionation curves. The δ17O’ values were obtained from the linear δ -values
by the following relationship: δ17O’ = δ17O’ – 0.528 x δ18O’, .Δ17O’ values of zero define
the terrestrial mass-fractionation line, and Δ17O’ values deviating from zero indicate
mass-independent isotope fractionation.
Hydrogen isotopes (UNM)
Hydrogen isotope analyses of NWA 7034 were performd by a thermal
combustion elemental analyzer (Finnigan TC-EA) connected to a gas chromatograph, a
He-dilution system (Finnigan CONFLO II) interface, and a Finnigan DeltaXLPlus dual
inlet isotope ratio mass spectrometer with continuous flow abilities for hydrogen. The
technique involves reduction of solid hydrous samples by reaction with glassy carbon at
high temperatures. H2 and CO are produced by reaction with the carbon at 1450°C in a
He carrier gas. Product gases are separated in a gas chromatograph and analyzed in a
mass spectrometer configured to make hydrogen isotope analyses in continuous flow
6
16. mode, with the reference hydrogen gas being introduced from the bellows system of the
dual inlet [49]. Solid materials (several mg) for bulk analyses were wrapped in silver foil
and dropped into the furnace using an autosampler. Using standard correction procedures,
results obtained with this method are identical to those obtained conventionally with a
precision for water samples of +/-2‰ (1o). Total time of analysis is less than 2 minutes
for a single hydrogen isotope analysis. For stepwise heating, the sample was placed in a
quartz- or ceramic-tube, held in place by quartz wool, and heated by external furnaces.
The sample was allowed to dry under He-flow at 50°C prior to gradual increase of the
furnace temperature to the desired temperature. Evolving water was collected in a liquid
nitrogen trap. Upon reaching of the required dwell time, the collected water was released
into the TC-EA for combustion, and processed as described above. Weight % H2O of the
samples analyzed were calculated by relating the peak-area of the sample to that of the
international biotite standard NBS-30 (3.5 wt. % H2O).
7
17. Fig. S1.
Backscatter electron image of spherical gabbroic clast composed of fine grained feldspar
(dark), pyroxene (light gray), and magnetite and maghemite (white).
8
18. Fig. S2
Backscatter electron image of an apatite-ilmenite-alkali feldspar cluster. White elongate
crystal is ilmenite, light gray crystals are Cl-apatite, medium dark crystals are andesine
(Na-Ca plagioclase feldspar), darkest crystals are sanidine (K-feldspar), white fine
grained crystals are magnetite or other iron-oxide.
9
19. <insert page break then Fig S3 here>
Fig. S3
Backscatter electron image of a portion of a ~1-cm quench melt clast with skeletal
pyroxene (dark gray) and olivine (light gray) set in a fine grained to glassy quench crystal
matrix.
10
20. Fig. S4
Backscatter electron image of a magnetite/maghemite-rich “reaction sphere”. White, fine
grained phase is magnetite or maghemite, medium and dark phases are very fine
intergrowths of pyroxene and feldspar.
11
21. Or
0
100
10
90
20
80
30
70
40
60
50
50
60
40
70
30
80
20
90
10
100
0
Ab 0 10 20 30 40 50 60 70 80 90 100
An
All Feldspar NWA 7034
Fig. S5
Ternary diagram showing the range of feldspar compositions present in NWA 7034 (cyan
dots, 178 electron microprobe analyses, molar percent). The range in feldspar
compositions displayed by NWA 7034 is much broader than what has been measured in
the shergottites [10], although it matches fairly well with feldspar compositions in
Chassigny [11]. Ab=albite An=anorthite Or=orthoclase.
12
22. All Pyroxene NWA 7034
DI HD
EN FS
0 20 40 60 80 100
Fig. S6
Pyroxene quadrilateral showing the range of compositions present in NWA 7034 (cyan
dots, 410 electron microprobe analyses, molar percent). There are two main clusters of
pyroxenes: 1) a high calcium augitic cluster and 2) a low calcium orthopyroxene cluster
that becomes pigeonitic with increasing ferrosilite. EN=enstatite FS-ferrosilite
DI=diopside HD=hedenbergite.
13
23. Fig. S7
Mg/Si Al/Si diagram modified after McSween et al. [4]. Red dots are analyses from
Alpha-Proton-X-ray Spectrometer (APXS) of rocks and soils from the Spirit Rover at
Gusev Crater [5-6]. Yellow rectangle is the average martian crust as measured by the
Gamma Ray Spectrometer (GRS) on the Mars Odyssey Orbiter [7]. The cyan dot is the
mean value of bulk NWA 7034 as determined by 225 electron microprobe analyses (cyan
dots) of fine-grained groundmass with error bars giving one standard deviation.
14
24. Fig. S8
Ni versus Mg diagram modified after [71]. Red dots are analyses from Alpha-Proton-X-
ray Spectrometer (APXS) of rocks and soils from the Spirit Rover at Gusev Crater [5-6].
Yellow rectangle is the average martian crust as measured by the Gamma Ray
Spectrometer (GRS) on the Mars Odyssey Orbiter [7]. The cyan dot is the mean value of
bulk NWA 7034 as determined by 225 electron microprobe analyses of fine-grained
groundmass with error bars giving one standard deviation.
15
25. 100
S ample/C hondrite
50
NWA-7034 Whole Rock
25
NWA-7034 Leachate
10
La Ce Pr Nd S m E u Gd Tb Dy Ho Er Tm Yb Lu
Fig. S9
Chondrite-normalized REE pattern of NWA 7034 whole rock and leachate. The pattern,
with strong LREE/HREE enrichment (La/Yb)N=2.3 and pronounced Eu anomaly
(Eu/Eu*=0.67) appears to be from an evolved terrestrial planet crust. Some of the
LREE/HREE enrichment is likely to have been inherited from the source. In addition the
sample has high 232Th/238U (K-value) of 5.2 (Table S1), which also likely represents
source enrichment.
16
26. 100
50
NWA 7034 (WR)
S ample/C hondrite
25
Shergotty (WR)
10
Nakhla (WR)
Tissint (WR)
1
La Ce Pr Nd S m E u Gd Tb Dy Ho Er Tm Yb Lu
Fig. S10
Chondrite-normalized REE pattern of NWA 7034 whole rock compared with some SNC
meteorites. Shergotty [40] is a so-called enriched shergottite, Tissint [16] is a so-called
depleted shergottite, and Nakhla [40] shows LREE enrichment relative to HREE, with
negative slope, seen in most nakhlites.
17
27. 0.780
0.760 LGT&
87Sr&
86Sr& 0.740
DRK$2& WR&
0.720
DRK$3& DRK$1&
0.700
0.79 0.80 0.81 0.82 0.83 0.84 0.85 0.86 0.87
1&
(&&&&&&)&x100&
Sr&
Fig. S11
The inverse Sr concentration plotted against the 87Sr/86Sr ratio of the whole rock and
mineral separates. On such a diagram samples that are related by two-component mixing
would define a parabola. In this case there is no clear pattern, which is inconsistent with
the isotopic data being the result of two component mixing.
18
28. 0.780 ! 0.780 !
Model&
Measured& LGT&
0.760 ! 0.760 !
87Sr&
0.740 ! 0.740 !
86Sr&
WR&
DRK.2&
LGT&
0.720 ! 0.720 !
DRK.3& DRK.1&
0.700 ! 0.700 !
-0.25! 0.00! 0.25! 0.50! 0.75! 1.00!
Fig. S12
Results of two component mixing calculation based on the Sr concentration end members
(whole rock and the mineral fraction DRK-2). The red circles are model results, while
blue circles are measured values. Note the large divergence between the calculated and
measured values of the light mineral fraction (LGT).
19
29. 0.7700% LGT#
0.7500%
87Sr#
86Sr#
0.7300%
DRK+1# WR#
DRK+2# R²#=#0.99994#
DRK+3#
0.7100%
0% 20% 40% 60% 80%
Rb#(ppm)#
Fig. S13
The Rb concentration plotted against the 87Sr/86Sr ratio of the whole rock and mineral
separates. The near perfect relationship between the two values (R2 ~ 1) is a good
indication that variations in the 87Sr/86Sr values are the result of the time-integrated
radiogenic growth from 87Rb and not the results of mixing between end-members with
different 87Sr/86Sr values.
20
30. Age = 1957 ± 320 Ma
MSWD = 5.0
0.727
wr
0.725
87Sr/86Sr
0.723
The three
dark fraction
0.721 separates.
0.719
0.15 0.25 0.35 0.45
87Rb/86Sr
Fig. S14
Rb-Sr isochron constructed from the whole rock and dark mineral fractions, giving an
age, within error of the isochron that includes that light fraction. These data show that the
age is not simply controlled by the high 87Rb/86Sr light fraction.
21
31. Fig. S15
Light microscopy and CRIS images of a feldspar grain in NWA 7034 hosting mineral
inclusions A) light microscopy image of inclusions several microns below the surface of
a Feldspar grain. B-F) Confocal Raman Imaging Spectroscopy images of individual
phases identified in the field of view B) Feldspar, C) apatite, D) magnetite, E) pyroxene
F) reduced macromolecular carbon. All of the Raman peak positions used to generate the
Raman spectroscopic images B-F are the same as those described in [31, 67-68]. The
association of MMC with magnetite. The association of MMC with magnetite and
pyroxene with or without the presence of apatite has been seen in previous studies [30].
22
32. Fig. S16
Oxygen three isotope plot of CO2 obtained during step wise acid dissolution of Martian
meteorite NWA7034. Step1, 2 and 3 at 25o C indicate Ca rich phases of CO3 and step 4 at
150o C indicates Fe-Mn-Mg rich CO3 phase. For comparison oxygen triple isotopic
composition of CO2 obtained from Ca rich phase of CO3 of terrestrial soils from deserts
and carbonates from ALH84001 and Nakhlite martian meteorites are included. Oxygen
triple isotopic composition of water soluble sulfate in NWA 7034 is also shown.
23
38. NWA 7034 D/H bulk analyses (whole rock)
Bulk analyses (combustion)
δD‰ wt.% H 2 O
50 0.63
59 0.60
41 0.65
35 0.68
50 0.64
42 0.50
Step-wise heating (continuous flow): 3 runs
T range °C δD‰ time @ T (min) wt.% H 2 O % of total H 2 O
50-100 -142 38 0.10 17.89
100-150 -114 38 0.05 9.79
150-325 -88 38 0.22 40.12
325-493 143 38 0.15 27.82
493-804 327 38 0.02 4.39
50 -103 155 0.01 2.26
50-105 -125 38 0.02 4.98
105-150 -126 38 0.05 10.25
150-321 -91 38 0.19 39.72
321-505 220 38 0.19 40.17
505-804 274 120 0.01 1.59
804-1014 319 120 0.00 0.52
Hydrogen isotope values of bulk samples and of stepwise heated increments
(‰ relative to V-SMOW).
Weight % H2O calculated relating the peak-area of the sample to that of
the international standard NBS-30 ( 3.5 wt. % H2O)
Table S6.
29
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