Tracing crustal contamination along the Java segment of Sunda Arc, Indonesia Multi-scale

106 Pages·2012·13.52 MB·English

Goldschmidt 2012 Conference Abstracts
Tracing crustal contamination along Multi-scale modeling of transverse
the Java segment of Sunda Arc, reactive mixing in a coastal aquifer
Indonesia
H. M. NICK1,3*, A. RAOOF1, M. THULLNER1,2, P.A.G.
REGNIER3
JOLIS, E. M.1*, TROLL, V. R.1, 4, DEEGAN, F. M. 2,
1Faculty of Geosciences, Utrecht University, Utrecht, The
BLYTHE, L. S. 1, HARRIS, C.3, FREDA, C. 4, HILTON, D. 5,
Netherlands (*correspondence: [email protected], [email protected])
CHADWICK, J.6, VAN HELDEN, M.6 2Department of Environmental Microbiology, UFZ – Helmholtz
Centre for Environmental Research, Leipzig, Germany
1Dept. Earth Sciences, CEMPEG, Uppsala, Sweden ([email protected])
(*[email protected]) 3Department of Earth and Environmental Sciences, Université Libre
2 Lab. for Isotope Geology, SMNH, Stockhom, Sweden
de Bruxelles, Brussels, Belgium ([email protected])
3 Dept. of Geological Science, UCT, South Africa

4 Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy
The transverse mixing between freshwater and seawater in
5 Scripps Oceanographic Institute, San Diego, USA
6 Dept. Petrology, Vrije, Universiteit Amsterdam, Netherlands coastal aquifers is a key process controlling the chemistry of
submarine groundwater discharge (SGD). The quantification of such
Arc magmas typically display chemical and petrographic
mixing and its effects on the fate of reactive chemical compounds in
characteristics indicative of crustal input. Crustal contamination
can take place either in the mantle source region or as magma coastal waters are still the subject of debate. We developed reactive
traverses the crust (e.g. [1]). While source contamination is
transport model approaches to study the mechanisms responsible for
generally considered the dominant process (e.g. [2, 3, 4]),
crustal contamination in high level magma chambers has also controlling reactive mixing processes in coastal aquifers. These
been recognised at volcanic arcs (e.g. [5, 6]). In light of this, we
models employ hybrid numerical methods for solving flow and
aim to test the extent of upper crustal versus source
contamination along the Java segment of the Sunda arc, which, transport [1,2], and benefit from utilizing the biogeochemical
because of its variable upper crustal structure, is ideal for the
reaction network simulator (BRNS) [3].
task.
We present a detailed geochemical study of 7 volcanoes Critical to advancing our understanding is the study of the
along a traverse from Anak-Krakatau in the Sunda strait
interplay between reaction and flow. We particularly investigated the
through Java (Gede, Slamet, Merapi, Kelut, Kawah-Ijen) and
Bali (Batur). Using rock and mineral elemental geochemistry impact of dispersion, heterogeneity induced velocity variations and
and radiogenic (Sr, Nd and Pb) and, stable (O) isotopes, we
biogeochemical reactivities on reactive transport for density driven
show a correspondence between changes in composition of the
upper crust and the apparent degree of upper crustal flow scenarios representing seawater-groundwater-interface in
contamination. There is an increase in 87Sr/86Sr and δ18O, and a
coastal aquifers. Our numerical observation showed e.g., that for
decrease in 143Nd/144Nd from Krakatau towards Merapi,
indicating substantial input from the thick quasi-continental highly reactive dissolved organic carbon (DOC) degradation
basement beneath East and Central Java. Volcanoes to the east
processes are limited by the porous media properties controlling
of Merapi, and the Progo-Muria fault zone, where the upper
crust is thinner and increasingly oceanic in nature have lower dispersion, whereas for relatively less reactive DOC degradation is
87Sr/86Sr and δ18O, and higher 143Nd/144Nd indicating a stronger
controlled by reaction kinetics.
influence of the mantle source [7]. Our new data represent a
systematic and high-resolution arc-wide sampling effort that In general, we found three reactive flow regimes: reaction
allows us to distinguish the effects of the upper crust on the
compositional spectrum of individual volcanic systems along controlled, reaction-dispersion controlled and dispersion
the Sunda arc. controlled transport. This is supported by further simulations

utilizing pore-scale models to investigate these regimes at the

[1] Davidson, J.P, Hora, J.M, Garrison, J.M & Dungan, M.A smaller scale. Our results suggest that the chemical reactivity as
(2005), J. Geotherm. Res., 140, 157-170. well as dispersivity are important parameters governing the
[2] Hilton, D.R., Fischer, T.P. & Marty, B. (2002), Rev.
Mineral. Geochem., 47, 319-370. biogeochemical dynamics of SGD. Hence, an adequate
[3] Gertisser, R. & Keller, J. (2003). J. Petrol., 44, 457-489
representenation of these processes in the macro-scale models is
[4] Debaille, V., Doucelance, R., Weis, D., & Schiano, P.
(2005), Geochim. Cosmochim. Acta, 70,723-741. essential.
[5] Gasparon, M., Hilton, D.R., & Varne, R. (1994), Earth
Planet. Sci. Lett., 126, 15-22. [1] S.K. Matthai, et al. (2009) Transport in Porous Media 83, 289-
[6] Chadwick, J.P., Troll, V.R., Ginibre, C., Morgan, D., 318.
Gertisser, R., Waight, T.E. & Davidson, J.P. (2007), J. Petrol., [2] A. Raoof, et al. (2010) Vadose Zone Journal 9, 624-636.
48, 1793-1812. [3] P. Regnier, et al. (2002) Applied Mathematical Modeling 26,
[7] Whitford, D.J. (1975), Geochim. Cosmochim. Acta, 39,
913-927.

1287-1302.

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Goldschmidt 2012 Conference Abstracts
Mantle Evolution from Plate Heterogeneous mantle sources of the
Subduction to Post-orogenic alkaline-tholeiitic intraplate basalts
Extension: Evidence from Permo- from the Aleppo Plateau, NW Syria
Triassic Mafic Dike Swarms in
GEORGE S.-K. MA1,2*, JOHN MALPAS2, KATSUHIKO SUZUKI3,
Northern Tibet Plateau CHING-HUA LO4, KUO-LUNG WANG1, YOSHIYUKI IIZUKA1
AND COSTAS XENOPHONTOS2
CHANGQIAN MA1,2*, JINYANG ZHANG2, FUHAO
1IES, Academia Sinica, Taipei 11529, Taiwan,
XIONG2, BIN LIU2, JIAN HUANG2 AND BAIHUA WANG2
[email protected]
1 State Key Lab. of Geological Processes and Mineral Resources, 2Department of Earth Sciences, The University of Hong Kong, Hong
Wuhan, China, [email protected] (* presenting author) Kong
3IFREE, JAMSTEC, Japan
2 China University of Geosciences,Wuhan,China
4Department of Geosciences, National Taiwan University, Taiwan
Five large mafic dike swarms have been discovered within the
Mantle-derived magmas are characterised by considerable
~270 km-long Xiangride-Golmud segment of the East Kunlun belt,
chemical and isotopic variability that is difficult to reconcile with
Northern Tibet Plateau, which are named, from east to west, the
partial melting of a peridotite mantle alone. This reflects the
Balong, Binggou, Xiaomiao, Bairiqili and Nanshankou dyke swarms. presence of heterogeneities in the mantle, originated from, for
The number of dikes in a given swarm can vary from 10 to 42, and instance, recycled oceanic crust or metasomatised lithosphere [1, 2,
the width of individual dikes ranges from 0.1 to 5 m. Most of the 3]. Identification of such heterogeneities and thus the mineralogy of
the mantle source becomes more ambiguous because both crustal
dikes trend N-S. The widest dikes are clearly banded with coarser
contamination and crystal fractionation may mask important source
textures and more phenocrysts in the middle portions than in the
characteristics.
margins. Most of the dikes are porphyritic diabase with the coarser- We present age, chemical and isotopic data to constrain the
grained varieties grading into diorites. All of the mafic dikes are source and the chemical evolution of the continental alkaline-
tholeiitic intraplate magmas from the Aleppo Plateau and vicinity,
composed chiefly of clinopyroxene, plagioclase and amphibole.
NW Syria. With the aid of new 40Ar/39Ar ages, two phases of
Based on the field relationships, hornblende Ar-Ar and zircon volcanism have been recognised in the Miocene, ~19-18 Ma (Phase
U-Pb dating we consider that the dike swams were formed in three 1) and ~13.5-12 Ma (Phase 2), in the studied area. The chemical and
episodes; Early Permian, late Permian and Triassic to Late Triassic. isotopic compositions [87Sr/86Sr = 0.7036-0.7051, 143Nd/144Nd =
0.51269-0.51287 and (187Os/188Os) = 0.151-0.453] of the lavas
The Xiaomiao (277 Ma) and Binggou (225 Ma) mafic dikes are t
reflect the unequivocal influence of crustal assimilation and
calc-alkaline in composition with low ∑REE ((cid:728)100 ppm) and
fractional crystallisation. However, it is interpreted that the two
relatively flat, chondrite-normalized REE patterns with no Eu phases of volcanism likely sampled a mineralogically heterogeneous
anomalies. These rocks also have low Ni, Cr and V but are enriched source, as reflected by their compositional variations seen in the
in Rb, K, Pb and P, and depleted in Nb and Ta. In contrast, the Balong most-primitive, least contaminated magmas. Such variations are: (1)
relatively high Si, low Ti and trace-element contents in the Phase 1
dike swarms (253 Ma) have high ∑REE (~100 to >150 ppm(cid:709)and
lavas, consistent with partial melting of a largely peridotitic mantle
are enriched in HREE, with higher trace element contents than the
source; (2) relatively low Si, high Ti, Fe, Ca, P, alkalis, and L-
other dikes. The Xiaomiao and Binggou dike swarms have similar MREE/HREE, plus sub-chondritic Th-(U)/Nb, Pb/Ce and Zr/Sm in
Sr-Nd isotopic characteristics with ISr = 0.707-0.711 and εNd(t) the Phase 2 lavas, approaching compositions of experimental melts
of amphibole-rich metasomatic veins [3]. Thus, it is inferred that the
ranges from -3.4 to 3.9, whereas the Bairiqili (251 Ma) and Balong
Syrian lithosphere had been pervasively metasomatised and
dikes have somewhat more enriched and variable compositions, with
contained veins of amphibole-rich cumulates shortly before
ISr = 0.709-0.719 and εNd(t) ranging from -7.8 to -3.6. The volcanism, and that the changing compositions of the Phase 1 to
geochemical similarities of the Permin –Triassic East Kunlun, South Phase 2 lavas (increasing Si-undersaturation) reflected an increasing
Qiangtang and north Himalaya dike swarms and basalts indicate that contribution from the metasomatic vein-derived melts.

the north boundary of Gondwana reached the East Kunlun block at

that time. [1] Hofmann (1997) Nature 385, 219-229. [2] Jackson & Dasgupta
(2008) EPSL 276, 175-186. [3] Pilet et al. (2008) Science 320,
Further study of these dike swarms should lead to a better
916-919.
understanding of the influence of subducted slabs on the mantle
source and subduction mechanics during the evolutionary stage
between the Paleo-Tethyan oceanic plate subduction and post-
orogenic extension.
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Goldschmidt 2012 Conference Abstracts
Using Uranium Isotopes to Determine Petrogenesis of the Aolunhua igneous
Salinity Sources in Rio Grande complex, eastern Central Asian
Waters Orogenic Belt: Geochemical, and Sr–
Nd–Hf isotopic constraints
LIN MA1*, ANNA SZYNKIEWICZ1, DAVID BORROK1, AND
JENNIFER C. MCINTOSH2 XINGHUA MA1*, BIN CHEN1,2, AND ZHIQIANG WANG1
1Department of Geological Sciences, University of Texas at El Paso,
1Key Laboratory of Orogenic Belts and Crustal Evolution, Peking
El Paso, TX 79968, USA, [email protected] (* presenting author),
University, Beijing 100871, China,
[email protected], [email protected]
[email protected] (* presenting author)
2Department of Hydrology and Water Resources, University of
2Institute of Geology and Exploration Engineering, Xinjiang
Arizona, Tucson, AZ 85721, USA, [email protected]
University, Urumchi 830046, China,

[email protected]
Abstract

The Rio Grande flows from Southern Colorado through New
A large-scale Early Cretaceous magmatic-metallogenic belt
Mexico and West Texas down to the Gulf of Mexico. It serves as an
(known as the Xar moron belt) has recently been recognized in the
important water supply for agricutural and municipal needs. In Rio
eastern Central Asian Orogenic Belt (CAOB), but the process and
Grande waters, total dissolved solids (TDS) increase from ~40 mg/L
mechanism for the formation of this belt are controversial. Here we
at the headwaters to 500-1500 mg/L at El Paso, Texas. The elevated
report geochemical and Sr–Nd–Hf isotopic data for the Aolunhua
TDS values in downstream water cause various problems such as
igneous complex (genetically related to a porphyry-type Mo
reduction in crop productivity and deterioration of soil quality due
deposit), to reveal its petrogenesis, source nature, and implications
to salt loading. A number of natural and anthropogenic factors may
for the Mesozoic tectonic evolution of eastern CAOB.
lead to increased salinity, so the exact sources and their relative
The complex consists of a batholith (monzogranite-porphyry)
contributions to the salt load remain unclear. U isotopes (e.g., 234U
and late-stage bimodal dyke swarms (quartz-porphyry and diorite
and 238U) fractionate naturally when released from rocks to waters
dykes). Geochemically, the monzogranite-porphyry exhibits features
during chemical weathering processes at Earth’s surface. It has been
of arc rocks such as conspicuous Nb, Ta negative anomalies and
suggested that the degree of U isotope fractionation depends largely
LILE enrichment (e.g., Sr and Ba). It has low I , positive ε (t) values
sr Nd
on local lithology and climate conditions, which affect chemical
of +0.5 to +1.4 and ε (t) values of +3.5 to +9.8. These features,
Hf
weathering and U release rates. U isotopes in natural waters thus
together with young inherited zircons (< 360 Ma) from the source
have great potential to serve as natural tracers for chemical
region, suggest a juvenile basement dominated by the late Paleozoic
weathering processes, which in turn can help to determine the
island-arc series. The mafic enclaves hosted in the monzogranite-
origins of dissolved solids (i.e., salts) and their history.
porphyry are characterized by containing HO-bearing minerals (e.g.,
2
Here, we measured the U concentrations and isotope ratios for
Hb and Bi) and more calcic plagioclases, variable elements
water samples collected along a ~ 1000 km stretch of Rio Grande compositions, high Mg#, enrichment of Sr and LREE, and radiogenic
(from the headwaters in Colorado to El Paso, Texas), as well as from
Nd-Hf isotopic compositions (ε (t) = +0.7 to +1.6 and ε (t) =
Nd Hf
streams and springs in the Jemez Mountains, a small drainage basin
+3.3 to +10.9), indicating that they originated from a subduction-
that recharges to Rio Grande in northern New Mexico. The
modified mantle, followed by a significant fractionation of
comparison of these two case studies reveals different evolution
ferromagnesian phases such as pyroxene and hornblende.
histories for U in surface waters. In the Jemez Mountain region
Petrological and geochemical evidences including hornblende-
where human impacts are minimal, U isotope ratios in surface
rimmed quartz ocelli, pervasive acicular apatites in mafic enclaves,
waters are largely controlled by rhyolite weathering, and both U compositional disequilibrium in plagioclases and high Mg# features
concentrations (0.01-0.19 ppb) and (234U/238U) activity ratios (1.5-
of the host rocks, demonstrate that mixing between mantle magma
3.0) vary systematically with elevation (2600-2900 m). Here,
and crustal melts have played an important role in the formation of
solutes in streams largely represent mixing of two sources: young
monzogranite-porphyry. The quartz-porphyry dykes show high SiO
2
surface water (e.g., several months old) with low U concentrations concentrations, low Mg#, conspicuous negative Eu anomalies and
and high (234U/238U) ratios and relatively old shallow groundwater
relatively flat REE patterns. The contemporaneous diorite dykes,
that has higher U concentrations and lower (234U/238U) ratios.
however, show geochemical and isotopic characteristics similar to
Similar ranges of U concentrations and (234U/238U) ratios are
the mafic enclaves. The two kinds of dykes probably have been
observed for the headwater regions of the Rio Grande. U
originated from melting of lower crust and mantle source,
concentrations in the Rio Grande increase significantly downstream
respectively, in a late stage when the monzogranite-porphyry
(0.12 to 5.97 ppb) and correlate well with Ca2+, Mg2+, and HCO-
3 batholiths was solidified.
ions, revealing a control of carbonate dissolution/precipitation on
In summary, the Aolunhua igneous complex formed due to the
river water chemistry. This is probaly due to a change of lithology. In
reactivation of the juvenile CAOB in the Early Cretaceous when the
addition, both (234U/238U) ratios (1.6-2.1) and U concentrations in
Paleo-Pacific oceanic slab subducted beneath eastern China, and
the Rio Grande waters show strong seasonal patterns, reflecting the
triggered the upwelling of asthenosphere, which resulted in
human impacts on river chemistry, such as the regulation of river lithospheric thinning and extensive magmatism in the eastern CAOB.
flows by reservoirs and dams, agricultural irrigation return flows,
and pumping of cold/geothermal aquifer waters.
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Goldschmidt 2012 Conference Abstracts
Investigations into temporal and Metagenome-enabled investigation of
spatial variations in atmospheric microbial sulfur precipitation in a
helium isotopes carbonate aquifer
J.C. MABRY1*, B. MARTY1, P. BURNARD1 JENNIFER L. MACALADY1*, DANIEL S. JONES1, IRENE
1CRPG-CNRS, 54501 Nancy, France (*correspondence: SCHAPERDOTH1, CLARA CHAN2 AND KEVIN CABANISS2
[email protected]) 1Penn State University, Geosciences Dept., University Park, PA,
USA (*presenting author, [email protected])
This work describes the development of a method to measure 2Univ of Delaware, Earth, Ocean & Environment, Newark, DE, USA
atmospheric helium isotopes at a very high precision (0.2% or
better). The primary motivation is to look for potential temporal or Microbial coupling between carbon and sulfur elemental cycles
spatial variations in the helium isotopic composition of the in iron-poor, carbonate-rich environments results in the dissolution
atmosphere. Since crustal helium has a large excess of 4He relative of carbonate minerals, precipitation of gypsum, and/or the
to atmospheric helium, recent anthropogenic activities such as fossil precipiation and dissolution of elemental S. In particular, the
fuel exploitation may give rise to a change in the atmospheric incomplete oxidation of sulfide to elemental S strongly affects the
composition [1, 2]. However, previous measurements have put an availability of H2S and H2SO4, acids which contribute to limestone
upper limit on this near current measurement abilities [3, 4]. There dissolution. The sulfidic Frasassi caves provide a superb model
are significant analytical challenges to improving the precision of environment for understanding biotic and abiotic controls on the
atmospheric helium measurments as helium is only present in trace balance of these processes, which affect porosity development and
quantities in the air (5.24 ppm) and there are are many of orders of fluid flow in sedimentary aquifers and the diagenesis of marine
magnitude difference in the abundance of the two isotopes carbonates.
(3He/4He = 1.38 ×10-6). In the Frasassi system, four types of sulfide-oxidizing biofilm
air
To improve our ability to measure helium isotopes precisely, communities develop in separate niches defined by dissolved
we have constructed an automated extraction line which can rapidly sulfide:oxygen ratios and hydrodynamic shear [1]. Elemental
switch between measuring aliquots of sample with standards. For analyses suggest that S precipitates most rapidly in locations where
each measurement we purify a relatively large amount of gas (~20 turbulent mixing brings sulfidic water in contact with cave air,
cm3) so that we can make many repeat analyses of the same sample resulting in biofilms that are 40-80% sulfur by mass. Major
gas. A major component of our method features an adjustable populations in the biofilms include members of widely-dispersed
bellows on the sample aliquot volume that enables us to adjust the and uncultivated sulfur-oxidizing clades, including
size of a sample aliquot to precisely match the standard, eliminating Gammaproteobacteria related to "Thiobacillus baregensis" (Tbar) and
biases arising from nonlinear pressure effects in the mass Sulfurovumales-group Epsilonproteobacteria. Based on FISH
spectrometer. population counts with genus and group-specific probes,
Prior to analysis we remove the neon (and any other gases Sulfurovumales are successful only when the sulfide:oxygen ratio
remaining after purification) with a cryo trap. This lowers the exceeds 150. In contrast, Tbar populations are not correlated with
pressure in the mass spectrometer and makes it easier to be sure that concentrations of sulfide, oxygen, or the dissolved sulfide:oxygen
the standard and sample aliquots are the same size. There is an ratio.
additional cryo trap on the mass spectrometer volume to maintain To further investigate the geochemical and ecological factors
low background levels. Adding the cryo trap reduced the statistical that favor the growth of Tbar and Sulfurovumales populations, and
errors of repeated standard analysis within one day from 0.5% to implications for sulfur precipitation and limestone dissolution, we
0.3% (2σ). Meanwhile the absolute scatter of measurements over investigated the metabolic capabilities of the sulfur-precipitating
several days fell from ~5% before the addition of the cryo trap to biofilms using enrichment culturing and metagenomics. Initial
better than 0.5%. We believe much of this remaining scatter can be enrichment culturing efforts suggest that Tbar and Sulfurovumales
attributed to an instability discovered in the high voltage power populations are autotrophic or mixotrophic, and that batch (rather
supply of the source. than flow-through) culturing methods favor the growth of Tbar over
All of the previous measurements were made on a GV Sulfurovumales. Four metagenomes derived from biofilms naturally
Instruments Helix split flight tube multi-collector mass enriched in Tbar and Sulfurovumales populations are currently in
spectrometer, which was specifically designed for helium isotope production, and will provide genetic clues necessary to enhance
measurements. Future measurements will be made on a new version enrichment culturing efforts and constrain the metabolic potential of
of the same machine built by Thermo Scientific and recently these ecologically successful groups, including pathways for partial
installed in our lab (January 2012). The new machine has already or complete S oxidation, S reduction, C and N fixation,
demonstrated approximately three times higher sensitivity as well as heterotrophy, and biofilm formation.
better electronic stability. First results with the new machine will be
presented at the conference.
[1] Oliver et al. (1984) GCA 48, 1759-1767. [2] Pierson- [1] Macalady (2008) ISME Journal 2, 590-601.
Wickman et al. (2001) EPSL 194, 165-175. [3] Sano et al. (2010)
GCA 74, 4893-4901. [4] Lupton and Evans (2004) GRL 31, L13101.

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Goldschmidt 2012 Conference Abstracts
Isotopic and mineralogical properties In Situ Determination of Sulfide
of surface sediment from the circum Oxidation Rates in the Green Sulfur
Arctic Bacterium Chlorobaculum tepidum
JENNY MACCALI1*, CLAUDE HILLAIRE-MARCEL1 Daniel J. MacDonald1*, Alyssa Findlay1, Kevin Shuman1,
Daniel Hess1, Thomas E. Hanson1, and George W. Luther1
1GEOTOP-UQAM, Montréal, Canada, [email protected] (*
presenting author) 1College of Earth, Ocean, and Environment, University of

Delaware, Lewes, DE 19958

*[email protected]
Radiogenic isotopes (RI) have been used to trace sediment

origin in various ocean basins [1, 2, 3, 4, 5, 6]. This method is Sulfur cycling in many environments is regulated by
particularly useful in sites where ire-rafting deposition (IRD) microbial activity. As the most reduced form of sulfur, H S, is toxic
2
represents an important sediment transport mechanism, as illustrated to many aerobic organisms; however, Chlorobaculum tepidum uses
recently by RI-analyses in cored sediments from Fram Strait [7], the sulfide as an electron donor during photosynthesis. Microbial
sulfide oxidation is a major sulfide removal mechanism, yet the
main sea-ice exit pathway from the Arctic Ocean towards the North
relevant microbial oxidation rates are relatively unknown. In a
Atlantic. Mineral-lattice bound Pb-, Sr- and Nd- isotopes (i.e., linked
recent study biological sulfide oxidation rates were determined to
to detrital sediment supplies) from this sedimentary sequence exceed abiotic oxidation rates by several orders of magnitude1.
displayed two distinct temporal trends since the Last glacial Voltammetric data will be presented that examines the rate of
Maximum [7]. In this study, three main detrital supply areas were sulfide loss due to microbial uptake and oxidation over a variety of
defined, based on literature data, respectively, the Canadian and physical and biochemical parameters, such as the effects of light
Russian margins, and northern Greenland. Broad sea-ice intensity, biomass concentration and total sulfide concentration.
Speciation of sulfide oxidation products, such as elemental sulfur
paleocirculation patterns were then proposed based on the Fram
and polysulfides, and the rates at which these products form, will be
Strait RI-record. In order to refine sea-ice paleo-circulation
presented. Initial data show that these organisms follow Michaelis-
reconstructions, we have undertaken a more detailed survey of Menten kinetics with an approximate apparent saturation rate of 100
potential circum-Arctic sediment sources, using surface-sediment (cid:80)M sulfide.
samples from the Canadian Arctic Archipelago, the Beaufort Shelf,
Bering Strait, the Chukchi Sea, the East Siberian, Laptev, Kara and
Barents seas. Nd- and Sr- isotope data now define more detailed
isotopic domains with, for instance, low epsilon Nd values
corresponding to North American cratons, and high epsilon Nd [1] Luther et. al. (2011) “Thermodynamics and Kinetics of sulfide
values linked to Pacific inputs through Bering Strait. These domains oxidation by oxygen: a look at inorganically controlled reactions
are compared with relevent mineralogical information (e.g. iron- and biologically mediated processes in the environment”
oxides) from Darby [8]. This ‘RI-mapping’ data set should improve Frontiers in Microbiology. 2.

quantitative estimates of IRD sources and mixing in sedimentary
records from the Arctic, thus of the dynamics of surrounding
continental ice-margins during the Quaternary.

[1] Fagel et al. (2004) Paleoceanography 19, 1-16. [2] Frank et al.
(2002) Reviews of Geophysics 40, 1-38. [3] Haley et al. (2008)
Paleoceanography 23. [4] Tütken et al. (2002) Marine Geology
182, 351-372. [5] Winter et al. (1997) Geochimica and
Cosmochimica Acta 19, 4181-4200. [6] O’Nions et al. (1978)
Nature 273, 435-438. [7] Maccali et al. (2012) Paleoceanography
27. [8] Darby (2003) Journal of Geophysical Research: Oceans
108, 13-1.

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Goldschmidt 2012 Conference Abstracts
Natural-abundance stable Surface complexation modeling of
carbon isotopes of small-subunit Na+ and Rb+ adsorption by rutile to
ribosomal RNA (SSU rRNA): 250oC
first results from Guaymas
MICHAEL L. MACHESKY1*, MILAN PŘEDOTA2, MOIRA K.
Basin (Mexico) RIDLEY3, AND DAVID J. WESOLOWSKI4
1Univ. of Illinois, Illinois State Water Survey, Champaign IL, USA,
BARBARA J. MACGREGOR*, HOWARD MENDLOVITZ,
[email protected] (* presenting author)
DANIEL ALBERT, AND ANDREAS P. TESKE 2Univ. South Bohemia, České Budějovice, Czech Republic,

[email protected]
University of North Carolina, Dept. of Marine Sciences
*[email protected], [email protected], 3Texas Tech Univ., Dept. of Geosciences, Lubbock, TX, USA,
[email protected], [email protected] [email protected]
4Oak Ridge National Laboratory, Oak Ridge, TN, USA,
Introduction
[email protected]
Small-subunit ribosomal RNA (SSU rRNA) is a

phylogenetically informative molecule found in all cells.
Surface complexation models (SCMs) provide the means to
Being poorly preserved in most environments, it is a useful
marker for active microbial populations. At Guaymas Basin, rationalize and extend (to uncharacterized conditions) cation
hydrothermal fluids interact with abundant sedimentary adsorption data, and increasing use is being made of molecular level
organic carbon to produce natural gas and petroleum. Where experimental and/or modeling results to constrain SCM parameter
this reaches the sediment surface, it can support dense
space. One rather surprising finding of this molecular-level
patches of seafloor life, including Beggiatoa mats. We report
information is that monovalent alkali metal cations can bind in inner-
here on the stable carbon isotopic composition of SSU rRNA
from a Beggiatoa mat transect, a cold background site, and a sphere fashion to oxides such as rutile. Given the very common use
warm site with high oil concentration. Our initial hypotheses of alkali metal salts as background electrolyte media for adsorption
were that rRNA isotopic composition would be strongly experiments, it therefore becomes necessary to incorporate inner-
influenced by methane supply, and that archaeal rRNA might
sphere adsorption of alkali metal cations into SCMs to best
be lighter than bacterial due to contributions from
represent molecular-level reality.
methanogens and anaerobic methane oxidizers.
Ridley et al [1] demonstrated that the CD-MUSIC model of
Results and Conclusion Hiemstra, van Riemsdijk and co-workers can successfully
The central part of the mat overlay the steepest temperature accommodate inner-sphere binding of Na+, K+, and Rb+, as gleaned
gradient, and was visually dominated by orange Beggiatoa. from ab initio constrained classical molecular dynamics (CMD)
This was fringed by white Beggiatoa mat and bare, but still simulations (for Na+, Rb+) and X-ray reflectivity measurements (for
warm, sediment. Methane concentrations were saturating
Rb+) in fitting 25oC rutile surface titration data. We have extended
beneath the mat and at the oily site, lower beneath bare
sediment, and below detection at the background site. this CD-MUSIC approach to rutile surface titration data collected to
250oC in NaCl, NaTr(Tr=triflate) and RbCl electrolyte solutions.
CMD results that track Na+ and Rb+ adsorption by the 110 surface of
rutile at 25, 150, and 250oC and several charge states are used to
constrain the allowable CD-MUSIC model parameters and it is
shown that the resulting SCM can adequately mirror most of the
CMD results over the broad ambient to hydrothermal temperature
range.
Figure 1. Stable carbon isotope composition of rRNA
captured by magnetic bead capture hybridization [1].

We used biotin-labeled oligonucleotides to capture [1] Ridley et al. (2009) Geochim. Cosmochim. Acta 73, 1841-1856.
Bacterial and Archaeal SSU rRNA for isotopic determination
(Fig. 1). Background-site rRNA was isotopically heaviest,
and bacterial RNA from below 2 cm at the oily site was
lightest, consistent with control by methane. Within the mat,
however, rRNA from the bare periphery was lightest. There
was no consistent isotopic difference between the probes,
although RNA recoveries were too low for capture at depths
where methanogens and methane oxidizers are expected.
Our prediction that rRNA isotopes would correlate
directly with methane supply was clearly oversimplified.
Future work will include the isotopic characterization of
other potential carbon substrates. We are also investigating
Gulf of Mexico sediments, where methane is significantly
more 13C-depleted than at Guaymas Basin.

[1] Miyatake et al. (2009) Appl. Environ. Microbiol. 75,
4927-4935.
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Goldschmidt 2012 Conference Abstracts
Discharge-driven harmful algal Nanodiamonds and carbonaceous
blooms in the NE Gulf of Mexico grains in Bull Creek Valley,
Oklahoma
H.L. MACINTYRE1*, J.D. LIEFER2, L. NOVOVESKA2, W.C.
BURNETT3, N. SRU.H3,. K P.ETT.E ERLSLOENR53 A, WND.L R. .SFM. VITIHSO4,5 C .P. DORSEY4, BAEMNDENRETW2, BSR. IMANA DJ.D CENA1R*T, EARN3,D ARELWEX L R. .S SWIMINMDSL4E, 1A, NLDE LMANODUR CA.D
1Dalhousie University, Halifax, Canada, [email protected] (* BENAMARA5
presenting author)
1University of Oklahoma, Norman OK, USA, [email protected] (*
2Dauphin Island Sea Lab, Dauphin Island, USA,
presenting author), [email protected]
[email protected], [email protected]
2Oklahoma Archaeological Survey, Norman OK, USA,
3Florida State University, Tallahassee, USA, [email protected],
[email protected]
[email protected], [email protected]
3Oklahoma State University, Stillwater OK, USA,
4Alabama Department of Public Health, Mobile, USA,
[email protected]
[email protected], [email protected]
4University of California Santa Barbara, Santa Barbara CA, USA,
5Coastal Carolina University, Conway, USA, [email protected],
[email protected]
[email protected]
5University of Arkansas, Fayetteville AR, USA, [email protected]

The state of Alabama (USA) has only 100 km of coastline

but has had recurring harmful algal blooms (HABs) at two shallow-
Sediments in the Bull Creek Valley document the Pliestocene-
water hot-spots. Both are in the same hydrological unit on the
Holocene transition, including the period corresponding to the
eastern margin of Mobile Bay. The first, Weeks Bay, is a sub-estuary
Younger Dryas climate anomaly. Conflicting reports of
on the eastern margin of Mobile Bay and is the site of diverse
nanodiamond presence/ absence, spatial/ temporal distribution, and
dinoflagellate blooms that cause hypoxia and fish-kills. The second,
polymorphic phase identification [e.g., 1,2] are perhaps not
the Gulf of Mexico shoreline adjacent to Little Lagoon, a shallow
surprising given the challenges of recovering and identifying such
and saline lagoon, is the site of toxic blooms of the diatom Pseudo-
materials within bulk sediments. Nanodiamonds form
nitzschia spp. Initiation of both dinoflagellate and diatom blooms is
extraterrestrially; their distribution in Earth sediments may relate to
correlated with discharge from the aquifer.
the intensity of extraterrestrial bombardment. It has been suggested
Microalgal community composition appears to be driven by
that a nanodiamond spike in Younger Dryas strata records an impact
the interaction of temperature and submarine groundwater discharge.
event, contributing to cooling on a global to regional scale [1].
Dinoflagellates bloom in Weeks Bay during periods of low
For this study, sediments corresponding to alluvial, paleosol,
discharge in both winter (Prorocentrum minimum) and summer
and loess horizons were collected from multiple profiles across the
(Karlodinium veneficum). Pseudo-nitzschia spp. bloom
Bull Creek Valley at approximately 10 cm intervals. Carbon dates
predominantly in the spring after periods of high discharge [1], as
ranged from ~33,000 years before present to recent. The clay
part of a cohort of diatoms that includes other bloom-forming taxa
fraction was separated from the bulk soil and then digested by a
[2]. Comparison of community composition with physico-chemical
series of strong acid treatments. Residues were resuspended in
characteristics of Little Lagoon showed a very high correlation
ammonium hydroxide and prepared for transmission electron
between the degree of dominance by diatoms and water age (inferred
microscopy (TEM) by centrifugation onto grids with carbon support
from the excess 224Ra:223Ra ratio) when subsurface resistivity
films. Grids were analyzed with TEM, high-resolution TEM
showed that the water table was high. There was no correlation
(HRTEM), energy-dispersive x-ray analysis (EDS), and electron
between community indices and water age when the water table was
energy loss spectroscopy (EELS).
low.
Nanodiamonds were identified in multiple horizons, including
The surficial aquifer is contaminated with very high N (up to
sediment dated to the Younger Dryas. Individual grains ranged from
c. 5 mM DIN plus DON) and the sediments in Weeks Bay and Little
approximately 3-50 nm, although most grains were 5-10 nm. Most
Lagoon have even higher concentrations of both N and P. Although
or all grains correspond to the n-diamond polymorph, as suggested
the supply of nutrients by groundwater is important in supporting
by lattice fringe spacings. Lesser amounts of cubic nanodiamonds
very dense blooms, the magnitude of discharge is likely as important
qwere also tentatively identified. EELS of these particles was
in structuring the community. The conditions under which both
consistent with sp3-bonded carbon. Other micron-scale particles
dinoflagellate and diatom blooms occur are consistent with
morphologically similar with those previously identified as
ordination of their niches in terms of habitat productivity and
hexagonal diamond [3] were graphene/graphane mixtures based on
stability [3]. Because global climate change is predicted to alter
electron diffraction and EELS.
seasonal patterns of precipitation, hence aquifer discharge, it is

likely that the niches for these HAB taxa will expand.
[1] Kennett et al. (2009) Science 323, 94. [2] Daulton et al. (2010)

PNAS 107, 16043-16047. [2] Kennett et al. (2009) PNAS 106,

12623-12628.
[1] Liefer et al. (2009) Harmful Algae 8: 706-714. [2] MacIntyre et

al. (2011) J. Plankt. Res. 33: 273–295. [3] Grime (1977) Amer.
Natur. 111: 1169-1194.

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Goldschmidt 2012 Conference Abstracts
Reactive transport in compacted Modeling Eu(III) sorption on granite
bentonite: porosity concepts,
K. MAEDA1*, K. FUKUSHI1, Y. HASEGAWA1, Y. YAMAMOTO2,
experiments and applications D. AOSAI2 AND T. MIZUNO2
URS MÄDER1*, ANDREAS JENNI1, RAÚL FERNÁNDEZ2, AND 1Kanazawa Univeristy, Kanazawa, Japan, [email protected]
ISABEL DE SOTO GARCÍA2 u.ac.jp (presenting author)
2Japan Atomic Energy Agency, Mizunami, Japan
1University of Bern, Geological Sciences, Bern, Switzerland
* [email protected], [email protected] There have been very few researches for the trace elements
2Universidad Autonóma de Madrid, Departamento de Geología y sorption on complex mineral assemblages such as rocks, sediments
Geoquímica, Madrid, Spain, and soils. In order to make predictions for the trace elements
[email protected],[email protected] migration on geologic media, it is crucial to understand the nano-
scale interaction of trace elements with complex mineral
Porosity concepts and scales assemblages, and to construct the thermodynamic sorption models
Chemical and transport processes in compacted bentonite are based on the molecular-scale information. In the present study, the
operating at the nanometer scale of smectite interlayers but cannot batch sorption experiments of Eu(III) on granite were conducted as
be resolved at this scale by analytical or imaging techniques. function of pH and ionic strength. The sorption behavior was
Porosity concepts are treated as macroscopic averaged properties modeled based on our microscopic observation (Hasegawa et al. this
but are based on the microscopic scale using electrostatics and volume).
explicit or averaged Poisson-Boltzman theory for the distribution of The granite sample was collected from a borehole at a depth of
electrolyte species adjacent to mineral surfaces bearing permanent 400 m from the Mizunami Underground Research Laboratory
charge. Implementation into reactive transport numerical models is constructed by Japan Atomic Energy Agency in central Japan. The
debated, ranging from an averaged single-phase solid-liquid granite was visually fresh. However, the microscope observation and
electrolyte [1] to complex multi-porous models assigning transport the X-ray diffraction analysis of clay fraction show the occurrences
parameters specific to each type of porosity [2]. Here, we examine of smectite, chlorite, vermiculate, calcite and hydrous iron oxides.
the relative merits and limitations of different multi-porous models Eu(III) sorption experiments on granite in the Teflon vessels were
as applied to experimental data of various complexity. conducted as function of pH (2 to 8), ionic strength (I=0.01 and 0.1)
and Eu concentration (1 and 10 uM) under ultra-pure N atmosphere
2
Reactive transport modelling of experimental data in room temperature.
A long-term multi-component advective-diffusive reactive The experiments and modeling results are shown in the Figure.
transport experiment with compacted bentonite can be modelled Sorption ratio of Eu(III) was almost zero at pH 2. They abruptly
satisfactorily with either a dual porous concept (small proportion of increase with pH up to 3.5. Above pH 3.5, the sorption ratio
charge-balanced “free” eletrolyte, large proportion of interlayer- indicates almost constant. The sorption strongly depends on ionic
type electrolyte with Donnan approximation), or more complex strength at the pH more than 3.5. Our microscopic observations
model assigning separate porosities to the interlayers and a pore show that Eu(III) is selectively scavenged by biotite and that sorption
space close to external surfaces of smectite particles. Transport of mode of Eu(III) is identified to be exchange reaction with inter-layer
the solvent was additionally constrained by a D2O tracer. K in biotite and Eu(III). The sorption behaviors at pH more than 3.5
Modelling of short-term simple major-component through- are consistent with the cation exchange reaction. At low pH
diffusion experiments is not discriminating between models of conditions, less than pH 3.5, the release of the Al and/or Fe must
various complexity and leads to a strong dependency of transport occur with dissolution of minerals. The Al and/or Fe should be
coefficients on the porosity concept. competed with Eu(III)
100
PHREEQC and Crunchflow were used as numerical models, on the exchange site
both capable of treating multiple porosities, electrostatics in the of biotite. The 80
form of diffuse-layer theory, and species-specific and porosity- sorption modeling is %)
specific transport properties. simply considering on ((60
R eferences [1] Birgersson M. & Karnland O. (2009) Geochim. iaonnd excshoalnugbeil irteya ctioonf Sorpti 40
Cosmochim. Acta, 73, 1908-1923. [2] Tournassat C. & Appelo hydrous iron oxide. 20 EEuu11(cid:547)(cid:547)MM(cid:2057)(cid:2057)NNaaCCll00..011MM
C.A.J. (2011) Geochim. Cosmochim. Acta, 75, 3698-3710. The model reasonably 0 EEuu1100(cid:547)(cid:547)MM(cid:2057)(cid:2057)NNaaCCll00..011MM
2 3 4 5 6 7
reproduces the
pH
overall sorption Fig. Sorption behavior of Eu(III) on granite
behavior.

Ref.: Y. Hasegawa, K. Fukushi, K. Maeda, Y. Yamamoto, D. Aosai
and T. Mizuno: “Identification and characterization of phase
governing Eu(III) uptake in granite by microscopic observations”, In
this volume
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Goldschmidt 2012 Conference Abstracts
More than just "brown layers": SIMS sputter pit volume estimation
Manganese in Quaternary Arctic in SHRIMP zircon analysis using an
Ocean sediments 18O - primary beam
2
C. MÄRZ1,2,*, A. STRATMANN2, J. MATTHIESSEN3, S.W. CHARLES W. MAGEE JR.1*, JIM FERRIS2, CHARLES W. MAGEE2
POULTON1, A.-K. MEINHARDT2, S. ECKERT2, B. SCHNETGER2, 1Australian Scientific Instruments, Canberra, Australia,
C. VOGT4, R STEIN3 AND H.-J. BRUMSACK2
[email protected] (* presenting author)
1School of Civil Engineering and Geosciences, Newcastle 2Evans Analytical Group, East Windsor NJ, USA
University, UK, [email protected] (* presenting author)
2Institut für Chemie und Biologie des Meeres, Carl-von-Ossietzky- Abstract
Universität Oldenburg, Germany A novel method of estimating the volume of sputtered material
3Alfred-Wegener-Institut für Polar- und Meeresforschung, was discovered while performing SHRIMP (Sensitive High-
Bremerhaven, Germany Resolution Ion MicroProbe) zircon U/Pb geochronology using an
4ZEKAM, Fachbereich Geowissenschaften/MARUM, Universität 18O2- primary beam. During analysis, the ratio of Th and U oxide
Bremen, Germany isotopologues was found to be equal for each individual spot.
Assuming that the U16O/U18O (or Th16O/Th18O) ratio was equal to
In Quaternary deposits of the Arctic Ocean, brown Mn-rich the 16O/18O ratio of the sputtered material, multiplying this by the
layers are well-known, widespread, but also debated features. Both total 18O primary beam fluence (true beam current times analytical
glacial-interglacial climatic variations (in river runoff, bottom water time) yields total sputtered oxygen. Dividing by the density of
ventilation etc.) and early diagenetic processes might explain the oxygen in the zircon crystal lattice (about 63 atoms per nm3) yields
sedimentary Mn distributions. We applied inorganic geochemical an analytical volume.
analyses to pore waters and sediments of two sediment cores from Comparison with pit volumes from AFM (Atomic Force
the western Arctic Mendeleev Ridge (RV Polarstern Expedition Microscopy) shows that this isotopic volume estimation agrees with
ARK-XXIII/3) [1]. Our results show that most brown layers are AFM pit measurements to within 10%. This relationship holds for
associated with detrital (ice-rafted) and biogenic carbonate primary beam impact energies from 5 to 15 kV.
enrichments. In addition, all Mn-rich layers are enriched in Fe This agreement in volume between isotopic and AFM
(oxyhydr)oxides, and in Co, Cu, Mo and Ni that were most probably measurements suggests that oxygen migration in the sputtering
scavenged by Mn/Fe (oxyhydr)oxides. Distinct bioturbation patterns process is limited. As oxygen activity is crucial to governing the
(i.e., brown burrows into the underlying sediments) suggest these Pb/U vs UO/U calibration that makes accurate SIMS U/Pb
metal enrichments formed close to the sediment–water interface. geochronology possible, further investigations are planned into
We infer that the metal-rich layers formed under warmer minerals such as baddeleyite, which calibrate poorly.
(interglacial/interstadial) conditions with an intensified continental As the SHRIMP duoplasmatron consumes only $50-$100 of
hydrological cycle and only seasonal sea ice cover. Metals were 18O per day, this method appears to be cost-competitive with paying
2
delivered to the ocean by rivers/sea ice/coastal erosion [2], while for analytical time on a second instrument for analytical volume
seasonal productivity increased the reactive organic matter export to determination. However, it requires that the sample and the primary
the sea floor. The coeval deposition of organic matter and Mn/Fe beam are the only sources of oxygen in the sputtering process.
(oxyhydr)oxides triggered an intense diagenetic Mn and Fe cycling
at the sediment-water interface. These climate-induced primary and
secondary processes resulted in the enrichments of Mn/Fe
(oxyhydr)oxides, scavenging of trace metals, and the degradation of
labile organic matter. With the onset of glacial/stadial conditions,
the riverine/erosive delivery of metals strongly decreased, a solid
sea ice cover terminated the production and export of fresh organic
matter, and gray-yellowish sediments with lower metal contents
were deposited. Our data do not support glacial/stadial bottom water
oxygen depletion that might have affected the Mn distribution.
Despite the climatic control on the composition of the brown
layers, pore water data show that diagenetic redistribution of Mn and
Mo is still affecting the deeper sediments. The degree of Mn
remobilisation (potentially causing complete dissolution of existing,
and formation of new Mn layers) largely depends on the availability
and reactivity of Mn (oxyhydr)oxides and organic matter.

[1] C. März, A. Stratmann, J. Matthiessen, A.-K. Meinhardt, S.
Eckert, B. Schnetger, C. Vogt, R. Stein, H.-J. Brumsack (2011)
Geochim. Cosmochim. Acta 75, 7668-7687.
[2] R.W. Macdonald and C. Gobeil (in press) Aquat. Geochem.
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Goldschmidt 2012 Conference Abstracts
Measurement of nitrous oxide Oxygen isotopes from Chinese caves:
isotopologues and isotopomers by the records not of monsoon rainfall but
MAT 253 Ultra circulation regime
PAUL MAGYAR1*, SEBASTIAN KOPF1, VICTORIA ORPHAN1 BARBARA A MAHER 1 * , ROY THOMPSON 2
AND JOHN EILER1 1University of Lancaster, Lancaster, UK, [email protected]
1California Institute of Technology, Pasadena, CA, USA, (* presenting author)
[email protected] (* presenting author) 2University of Edinburgh, [email protected]

The global budget of nitrous oxide is dominated by terrestrial Current interpretation of cave (cid:577)(cid:577)18O records
and marine biological sources and atmospheric sinks. Details of the Oxygen isotope variations in Chinese stalagmites have
budget remain unclear, including the cause of increasing been widely interpreted as a record of the amount of East Asian
summer monsoonal rainfall. This interpretation infers decreasing
atmospheric NO concentrations. Marine sources of NO include
2 2 monsoonal rainfall from the mid-Holocene and large, dipolar
denitrification and nitrification. Our understanding of the major rainfall oscillations within glaciations. However, the cave (cid:71)18O
microbial players in the nitrogen cycle has changed in recent years variations conflict with independent palaeoclimate proxies (cave
(for example, the nitrifying Archaea), and the overall contributions (cid:71)13C, loess/palaeosol magnetic properties, n-alkanes), which
of these organisms to N2O production and their isotopic signatures indicate no systematic decline in rainfall from the mid-Holocene,
are poorly constrained [1]. and no glacial rainfall maxima.
Here we examine the suitability of the MAT 253 Ultra, a new
high resolution gas source mass spectrometer [2], for measurements Mass balance calculations show moisture source is key
of rare, previously unanalyzed isotopologues and isotopomers of control
NO, including ‘clumped’ species and high-precision direct analysis Using mass balance calculations, we demonstrate that the cave
of2 17O-substituted species. Such measurements could provide (cid:71)18O variations cannot be accounted for by summer rainfall changes,
nor rainfall seasonality nor winter cooling, but instead reflect
additional constraints to the global cycle of NO, and in particular
2 changes in moisture source. A possible driver of the (cid:71)18O variations
offer a fresh opportunity for distinguishing among biosynthetic NO
2 in Chinese stalagmites is precessional forcing of inter-hemispheric
sources. Preliminary experiments include examining N2O produced temperature gradients, in a mechanism similar to that of the modern
by pure cultures of denitrifying bacteria. day Indian Ocean dipole. Through such forcing, Indian monsoon-
In the instrument’s ‘medium resolution’ setting (16 μm entrance sourced (cid:71)18O may have dominated at times of high boreal summer
slit; resolving power ~16-18,000, M/∆M), [14N15N18O + 15N14N18O] insolation, local Pacific-sourced moisture at low insolation.
is well resolved from 13C18O16O and the 15N18O fragment from Suppression of summer monsoonal rainfall during glacial stages may
17O18O. In zero-enrichment measurements, precision of 0.2‰ was reflect diminished sea and land surface temperatures and the
radiative impacts of increased regional dust fluxes.
achieved for mass 47 species and 0.4‰ for 15N18O; both equaled

counting statistics limits for the integration times used (11 and 17
minutes, respectively) and should be improved by increasing the
source pressure, reducing resolution (e.g., using a 20 μm entrance
slit) or increasing counting time. At mass 45, 14N17O is well
2
resolved from [14N15N16O + 15N14N16O], with external precision of
0.03‰ achieved after 11 minutes of integration (again, counting
statistics limited and potentially improvable).
By measuring both these species (as well as unsubstituted and
singly substituted isotopologues), the position-specific clumping
(i.e., clumping of 15N with 18O, and its dependence on site
preference of 15N) can be examined. Such measurements will
complement the information already available from N O site
2
preference measurements alone. Calculations suggest that site
preference of 15N in thermodynamically equilibrated NO will differ
2
by ~1‰ between 16O and 18O isotopologues [3]. A larger range of
signals could arise from photochemical and biological
fractionations. Precise measurement of 17O will enable detection of
even subtle contributions of atmospheric mass-independent
fractionation, or study of variations in mass laws of biological and
other fractionations.

[1] Santoro et al. (2011) Science 333, 1282-1285. [2] Eiler et
al. The MAT 253 Ultra — a novel high-resolution, multi-collector
gas source mass spectrometer. Goldschmidt 2012. [3] Wang et al.
(2004) Geochim. Cosmochim. Acta 68, 4779-4797.
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