Sulfur isotopes in diamonds reveal differences in continent construction

Neoproterozoic West African diamonds contain sulfide inclusions with mass-independently fractionated (MIF) sulfur isotopes that trace Archean surficial signatures into the mantle. Two episodes of subduction are recorded in these West African sulfide inclusions: thickening of the continental lithosphere through horizontal processes around 3 billion years ago and reworking and diamond growth around 650 million years ago. We find that the sulfur isotope record in worldwide diamond inclusions is consistent with changes in tectonic processes that formed the continental lithosphere in the Archean. Slave craton diamonds that formed 3.5 billion years ago do not contain any MIF sulfur. Younger diamonds from the Kaapvaal, Zimbabwe, and West African cratons do contain MIF sulfur, which suggests craton construction by advective thickening of mantle lithosphere through conventional subduction-style horizontal tectonics.

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Different causes of the delamination on the example of Caucasus and Kyrgyz Tien Shan collision zones.

10.5194/egusphere-egu2020-6412 ◽

2020 ◽

Author(s):

Irina Medved ◽

Ivan Koulakov ◽

Mikhail Buslov

Keyword(s):

Upper Mantle ◽

Lower Crust ◽

3D Models ◽

Tien Shan ◽

Gradual Transition ◽

Mantle Lithosphere ◽

Continental Lithosphere ◽

Low Velocity ◽

Mountain Areas ◽

Velocity Anomalies

The causes of delamination of the mantle lithosphere in collision zones is actively debated in the scientific community. The main discussions are focused on the initiation of sinking of the continental lithosphere into the asthenosphere to a depth. Most scientists believe that such kind of immersion is impossible. However, there are several articles showing that this process is nonetheless taking place. For example Kay and Kay, (1993), Faccenda, Minelli, Gerya, (2009), Ueda et. al., (2012) and others propose various mechanisms of delamination, for example: eclogitization of the mafic layer of the lower crust, the effect of convection in the upper mantle, or gradual transition of the oceanic subduction into continental collision. Does the mantle part of the lithosphere sink into the mantle or spread laterally, as described in [for example, Deep Geodynamics, 2001; Bird, 1991; Schmeling and Marquart, 1991]?To answer these questions, we study deep structures beneath the Caucasus and Kyrgyz Tien Shan collision zones. The studies were carried out on the basis of multiscale seismic tomography methods: regional and global. This approach made it possible to study heterogeneities both in the crust and in the upper mantle. The obtained 3D models of seismic heteroheneities reveal similar features for the both collision regions. Beneath the mountain areas, in the uppermost mantle and lower crust, we observe prominent low-velocity anomalies that possibly indicate thickening of the crust and missing (or strongly thinned) mantle part of the lithosphere. At the edges of the collision zones, we reveal inclined high-velocity anomalies appearing as continuations of the continental plates sinking underneath the collision zones, which can be interpreted as delaminating mantle parts of the continental lithosphere. &#160;Based on joint consideration of the tomography models with the existing models of tectonic evolution, we conclude that the mechanisms of delamination in the considered two regions are different. In Caucasus, the delamination could be gradually transformed from oceanic subduction that ended here approximately ~10-15 Ma. In the case of Tien Shan, the detachment of the mantle lithosphere could be triggered by the plume that existed beneath Central Tien Shan or by the eclogitization of the mafic layer of the lower crust.

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Explaining the Structure of the Archean Mass-Independent Sulfur Isotope Record

Science ◽

10.1126/science.1190298 ◽

2010 ◽

Vol 329 (5988) ◽

pp. 204-207 ◽

Cited By ~ 100

Author(s):

I. Halevy ◽

D. T. Johnston ◽

D. P. Schrag

Keyword(s):

Sulfur Isotope ◽

Isotope Record

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Continuous Deformation Versus Faulting Through the Continental Lithosphere of New Zealand

Science ◽

10.1126/science.286.5439.516 ◽

1999 ◽

Vol 286 (5439) ◽

pp. 516-519 ◽

Cited By ~ 111

Author(s):

Peter Molnar ◽

Helen J. Anderson ◽

Etienne Audoine ◽

Donna Eberhart-Phillips ◽

Ken R. Gledhill ◽

...

Keyword(s):

New Zealand ◽

Seismic Anisotropy ◽

Plate Motion ◽

Plate Boundaries ◽

Mantle Lithosphere ◽

Continental Lithosphere ◽

Continuous Deformation ◽

Alpine Fault ◽

Wave Splitting ◽

Rule Out

Seismic anisotropy and P-wave delays in New Zealand imply widespread deformation in the underlying mantle, not slip on a narrow fault zone, which is characteristic of plate boundaries in oceanic regions. Large magnitudes of shear-wave splitting and orientations of fast polarization parallel to the Alpine fault show that pervasive simple shear of the mantle lithosphere has accommodated the cumulative strike-slip plate motion. Variations inP-wave residuals across the Southern Alps rule out underthrusting of one slab of mantle lithosphere beneath another but permit continuous deformation of lithosphere shortened by about 100 kilometers since 6 to 7 million years ago.

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Trace Elements and Sulfur Isotopes of Sulfides in the Zhangquanzhuang Gold Deposit, Hebei Province, China: Implications for Physicochemical Conditions and Mineral Deposition Mechanisms

Minerals ◽

10.3390/min10121089 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1089

Author(s):

Shimin Zhen ◽

Dazhao Wang ◽

Xiaofei Yu ◽

Qingfei Wang ◽

Yongsheng Li ◽

...

Keyword(s):

Trace Element ◽

Gold Deposit ◽

Sulfur Isotope ◽

Sulfur Isotopes ◽

Stage Iii ◽

Northern Margin ◽

Physicochemical Conditions ◽

The North ◽

Mineral Deposition

The Zhangquanzhuang gold deposit is a special deposit in the Zhangjiakou district, on the northern margin of the North China Craton. It is characterized by the enrichment of sulfides, the scarcity of tellurides and zero to positive sulfur isotope compositions compared with the famous Dongping and Xiaoyingpan Te-Au-Ag deposit types of the same district. In this paper, we use the in-situ LA-(MC)-ICP-MS and bulk trace element concentrations of pyrite, and in-situ sulfur isotope compositions of sulfides, to study physicochemical conditions and mechanisms of mineral deposition in the Zhangquanzhuang deposit. Pyrite from stage I (PyI) contains high Te contents, pyrite from stage II (PyII) has the highest Co and Ni contents, and pyrite from stage III (PyIII) contains high Cr, Zn, Pb, Ag, Cu, Sb, Bi and Au contents. The calculated in-situ δ34SH2S values range from 0.9‰ to 6.1‰, and the values for stages I and II are higher than those for stage III. The mineral assemblages and trace element contents in pyrite show that large amounts of metals precipitated during stage III, in which the pH and logfO2 were constrained within the range of 4.1 to 5.2 and −36.9 to −32.1, respectively. Sulfidation and boiling derived from decreasing pressure may be the main mechanisms leading to mineral deposition in stage III. The Zhangquanzhuang gold deposit was formed in a mineral system that was different from the one that formed the Dongping and Xiaoyingpan Te-Au-Ag deposits, and should thus be called the “Zhangquanzhuang−type” deposit and considered a third gold deposit type in the Zhangjiakou ore field.

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Constraining the rise of oxygen with oxygen isotopes

Nature Communications ◽

10.1038/s41467-019-12883-2 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 1

Author(s):

B. A. Killingsworth ◽

P. Sansjofre ◽

P. Philippot ◽

P. Cartigny ◽

C. Thomazo ◽

...

Keyword(s):

Oxygen Isotopes ◽

Atmospheric Chemistry ◽

Meteoric Water ◽

Sulfur Isotope ◽

Sulfide Oxidation ◽

Sedimentary Rocks ◽

Sulfur Cycle ◽

Isotope Record ◽

Continental Weathering ◽

S Isotope

Abstract After permanent atmospheric oxygenation, anomalous sulfur isotope compositions were lost from sedimentary rocks, demonstrating that atmospheric chemistry ceded its control of Earth’s surficial sulfur cycle to weathering. However, mixed signals of anoxia and oxygenation in the sulfur isotope record between 2.5 to 2.3 billion years (Ga) ago require independent clarification, for example via oxygen isotopes in sulfate. Here we show <2.31 Ga sedimentary barium sulfates (barites) from the Turee Creek Basin, W. Australia with positive sulfur isotope anomalies of ∆33S up to + 1.55‰ and low δ18O down to −19.5‰. The unequivocal origin of this combination of signals is sulfide oxidation in meteoric water. Geochemical and sedimentary evidence suggests that these S-isotope anomalies were transferred from the paleo-continent under an oxygenated atmosphere. Our findings indicate that incipient oxidative continental weathering, ca. 2.8–2.5 Ga or earlier, may be diagnosed with such a combination of low δ18O and high ∆33S in sulfates.

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Multiple Sulfur Isotope Records of the 3.22 Ga Moodies Group, Barberton Greenstone Belt

Geosciences ◽

10.3390/geosciences10040145 ◽

2020 ◽

Vol 10 (4) ◽

pp. 145 ◽

Cited By ~ 1

Author(s):

Masafumi Saitoh ◽

Sami Nabhan ◽

Christophe Thomazo ◽

Nicolas Olivier ◽

Jean-François Moyen ◽

...

Keyword(s):

Mass Spectrometry ◽

Isotopic Composition ◽

Greenstone Belt ◽

Sulfur Isotope ◽

Secondary Ion Mass Spectrometry ◽

Sulfur Isotopes ◽

Volcanic Rocks ◽

Isotope Ratio Mass Spectrometry ◽

Sulfur Isotopic Composition ◽

Barberton Greenstone Belt

The Moodies Group, the uppermost unit in the Barberton Greenstone Belt (BGB) in South Africa, is a ~3.7-km-thick coarse clastic succession accumulated on terrestrial-to-shallow marine settings at around 3.22 Ga. The multiple sulfur isotopic composition of pyrite of Moodies intervals was newly obtained to examine the influence of these depositional settings on the sulfur isotope record. Conglomerate and sandstone rocks were collected from three synclines north of the Inyoka Fault of the central BGB, namely, the Eureka, Dycedale, and Saddleback synclines. The sulfur isotopic composition of pyrite was analyzed by Secondary Ion Mass Spectrometry (SIMS) for 6 samples from the three synclines and by Isotope Ratio Mass Spectrometry (IR-MS) for 17 samples from a stratigraphic section in the Saddleback Syncline. The present results show a signal of mass-independent fractionation of sulfur isotopes (S-MIF), although t-tests statistically demonstrated that the Moodies S-MIF signals (mostly 0‰ < ∆33S < +0.5‰) are significantly small compared to the signal of the older Paleoarchean (3.6–3.2 Ga) records. These peculiar signatures might be related to initial deposition of detrital pyrite of juvenile origin from the surrounding intrusive (tonalite–trondhjemite–granodiorite; TTG) and felsic volcanic rocks, and/or to secondary addition of hydrothermal sulfur during late metasomatism. Moreover, fast accumulation (~0.1–1 mm/year) of the Moodies sediments might have led to a reduced accumulation of sulfur derived from an atmospheric source during their deposition. As a result, the sulfur isotopic composition of the sediments may have become susceptible to the secondary addition of metasomatic sulfur on a mass balance point of view. The sulfur isotopic composition of Moodies pyrite is similar to the composition of sulfides from nearby gold mines. It suggests that, after the Moodies deposition, metasomatic pyrite formation commonly occurred north of the Inyoka Fault in the central BGB at 3.1–3.0 Ga.

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Compound Specific Stable Sulfur Isotope Analysis (δ34S and δ33S) of Organic Compounds Using Gas Chromatography Hyphenated with Multiple Collector Inductively Coupled Plasma Mass Spectrometry (GC-MC-ICPMS)

10.5194/egusphere-egu2020-13835 ◽

2020 ◽

Author(s):

Kümmel Steffen ◽

Gelman Faina ◽

Horst Axel ◽

Strauß Harald ◽

Gehre Matthias

Keyword(s):

Mass Spectrometry ◽

Gas Chromatography ◽

Organic Compounds ◽

Inductively Coupled Plasma ◽

Sulfur Isotope ◽

Sulfur Isotopes ◽

Isotope Analysis ◽

Inductively Coupled ◽

Plasma Mass Spectrometry ◽

Stable Sulfur Isotope

Stable sulfur isotope analysis is potentially applicable in various fields in forensics and environmental analytics to investigate the sources and degradation of organic compounds, many of them being priority pollutants in groundwater and the atmosphere. A broader use of sulfur isotopes of organic compounds in environmental studies is still hampered by the availability of precise and easy-to-use techniques. Here we present a method for the determination of stable sulfur isotope ratios using gas chromatography coupled with multiple-collector inductively coupled plasma mass spectrometry (GC-MC-ICPMS) which can be used for both &#948;34S and &#948;33S analysis. The method was evaluated using the reference materials IAEA-S-1, IAEA-S-2 and IAEA-S-3 which were converted offline to SF6 prior to analysis. Standardization was carried out by using a two-point calibration approach. The &#948;34S values obtained by our method are in good agreement (within analytical uncertainty) with the results obtained by the conventional dual inlet method. Additionally, the impact of the used mass resolution (low and medium), the influence of auto-protonation of sulfur isotopes and the effect of isobaric interferences of O2+ on the obtained isotopic ratios was investigated. The analytical precision (1&#963;) for &#948;34S and &#948;33S values was usually better than &#177;0.1 &#8240; for analytes containing >0.1 nmol S. Thus, the presented compound-specific online method should be sufficiently precise to address a wide variety of research questions involving mass independent isotope effects of sulfur-containing organic compounds to discriminate sources or biological and chemical reactions in the environment.

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Sulfur isotopic compositions of the lithospheric mantle sulfides from the Udachnaya pipe (Yakutia)

10.5194/egusphere-egu2020-21171 ◽

2020 ◽

Author(s):

Olga Ilyina ◽

Alexey Agashev ◽

Bertrand Moine

Keyword(s):

Lithospheric Mantle ◽

Sulfur Isotopes ◽

Basic Research ◽

Kimberlite Pipe ◽

West African ◽

Udachnaya Pipe ◽

Depleted Mantle ◽

Isotope Ratio Mass Spectrometer ◽

Isotope Study

Sulfide inclusions in Neoproterozoic West African diamonds have revealed mass-independently fractionated sulfur isotopes in them [Smit et.al., 2019]. This feature is a sign of Archean surface changes traced in the mantle. Here we present an S isotope study of the unique fresh mantle deep-seated peridotites, eclogites and pyroxenites with rare or without any secondary alterations from the Udachnaya-East pipe. This research will give better understanding the role of subduction in the formation of the lithospheric mantle under the Siberian craton. Sulfur isotopes (34S/32S which is denoted as &#948;34S) were measured in the sulfides from eclogites, peridotites and pyroxenites using an Isoprime isotope ratio mass spectrometer (IRMS) with classic configuration with 4 collectors. The sulfides from eclogites are pyrrotite, pentlandites and chalcopyrites. They have &#948;34S values from +0,67 to +3,08 per mil (&#8240;). Sulfides in peridotites are pyrrotite-pentlandite-chalcopyrites assemblages and they have &#948;34S values from +0,22 to +3,55 &#8240;. These &#948;34S values from eclogites and peridotites are broadly overlap with the field for depleted mantle and chondrites (-1,9 to +0,35&#8240;) [Labidi et.al., 2013; 2014]. Sulfides from pyroxenites are pyrrotite and they have &#948;34S values from -3,62 to +1,49 &#8240;. These &#948;34S values have a wider range than the estimates for depleted mantle. The &#948;34S values in our samples are close to those in the depleted mantle, but still have deviation from it and do not fractionated. Our data did not detect mass-independently fractionated sulfur isotopes in the mantle samples from the Udachnaya pipe. Thus subduction of the earth&#8217;s crust did not play role in the values of sulfur isotopes of the lithospheric mantle sampled by Udachnaya kimberlite pipe. The source of sulfur in these rocks probably was the astenospheric mantle.References<ol><li>Smit et. al., 2019</li> <li>Labidi et. al., 2013; 2014</li> </ol>This study was supported by the Russian Foundation for Basic Research &#8470; 18-05-70064

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Constraining the atmospheric OCS budget from sulfur isotopes

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2007260117 ◽

2020 ◽

Vol 117 (34) ◽

pp. 20447-20452

Author(s):

Shohei Hattori ◽

Kazuki Kamezaki ◽

Naohiro Yoshida

Keyword(s):

Asian Monsoon ◽

Sulfur Isotope ◽

Sulfur Isotopes ◽

Carbonyl Sulfide ◽

Anthropogenic Sources ◽

Anthropogenic Emissions ◽

Eastern Asia ◽

Keeling Plot ◽

The Western Pacific ◽

Sulfur Containing

Carbonyl sulfide (OCS), the most abundant sulfur-containing gas in the atmosphere, is used as a proxy for photosynthesis rate estimation. However, a large missing source of atmospheric OCS has been inferred. Sulfur isotope measurements (34S/32S ratio andδ34S) on OCS are a feasible tool to distinguish OCS sources from oceanic and anthropogenic emissions. Here we present the latitudinal (north–south) observations of OCS concentration andδ34S within Japan. The observedδ34S of OCS of 9.7 to 14.5‰ reflects source and sink effects. Particularly in winter, latitudinal decreases inδ34S values of OCS were found to be correlated with increases in OCS concentrations, resulting an intercept of (4.7 ± 0.8)‰ in the Keeling plot approach. This result implies the transport of anthropogenic OCS emissions from the Asian continent to the western Pacific by the Asian monsoon outflow. The estimated backgroundδ34S of OCS in eastern Asia is consistent with theδ34S of OCS previously reported in Israel and the Canary Islands, suggesting that the backgroundδ34S of OCS in the Northern Hemisphere ranges from 12.0 to 13.5‰. Our constructed sulfur isotopic mass balance of OCS revealed that anthropogenic sources, not merely oceanic sources, account for much of the missing source of atmospheric OCS.

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