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22. Sulfur isotope analyses using 3× elemental analysis/isotope ratio mass spectrometry: Saving helium and energy while reducing analytical time and costs.

Author

Spangenberg, Jorge E. and Bosco‐Santos, Alice

Subjects
*SULFUR isotopes, *NITROGEN isotopes, *ISOTOPIC analysis, *CARBON isotopes, *ENERGY shortages
Abstract

Rationale: Helium (He) and energy shortages have caused price increases and reduced their availability. Using three combustion reactions per acquisition of carbon and nitrogen isotope ratios saves 50% He and energy during the elemental analysis/isotope ratio mass spectrometry (EA/IRMS). This approach needs to be tested for sulfur isotope (δ34S) analyses. Methods: A new method to measure δ34S in three sequential combustion reactions within one EA/IRMS acquisition was developed. The same material or blank samples could be used in the three reactions. After SO2 was used, a N2 purging method was employed to prolong the lifetime of the valves in the EA/IRMS interface. The 3×EA/IRMS was applied to measure δ34S in precious samples, such as Ag2S from acid‐volatile and chromium‐reducible sulfur extracted with a multiple‐port setup. Results: The 3×EA/IRMS‐δ34S method was validated with replicate analyses of international reference materials and laboratory standards with a wide range of mineralogical compositions and δ34S values. The method provided a strategic advantage for the δ34S measurements of small precious samples (measured between blanks). The accuracy and precision of the 3×EA/IRMS values effectively matched those obtained using conventional EA/IRMS, with good agreement between the mean ± SD values and the recommended values with their uncertainties. Conclusions: Compared with the conventional EA/IRMS, the proposed method provides accurate and precise δ34S measurements of the sulfate and sulfide samples while saving approximately 50% of He, energy, SO2 reference gas, O2, analysis time, and cost. Notably, 3×EA/IRMS can provide up to three δ34S values unaffected by memory effects. [ABSTRACT FROM AUTHOR]

Published
2024
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26. Magnetostratigraphy and stable isotope stratigraphy of the middle-Eocene succession of the Ainsa basin (Spain): New age constraints and implications for sediment delivery to the deep waters

Author

Läuchli, Charlotte, Garcés, Miguel, Beamud, Elisabet, Valero, Luis, Honegger, Louis, Adatte, Thierry, Spangenberg, Jorge E., Clark, Julian, Puigdefàbregas, Cai, Fildani, Andrea, de Kaenel, Eric, Hunger, Teodoro, Nowak, Andres, and Castelltort, Sébastien

Published
2021
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38. Limited oxygen production in the Mesoarchean ocean

Author

Ossa, Frantz Ossa, Hofmann, Axel, Spangenberg, Jorge E., Poulton, Simon W., Stüeken, Eva E., Schoenberg, Ronny, Eickmann, Benjamin, Wille, Martin, Butler, Mike, and Bekker, Andrey

Published
2019

44. Middle Eocene Climatic Optimum (MECO) and its imprint in the continental Escanilla Formation, Spain.

Author

Sharma, Nikhil, Spangenberg, Jorge E., Adatte, Thierry, Vennemann, Torsten, Kocsis, László, Vérité, Jean, Valero, Luis, and Castelltort, Sébastien

Subjects
EOCENE Epoch, OXYGEN isotopes, CARBON isotopes, CLIMATE change, CHEMICAL weathering, STABLE isotopes, FLUVIAL geomorphology
Abstract

The Middle Eocene Climatic Optimum (MECO) is a global warming event mainly recognized in the marine domain and described less in the terrestrial environment. Here we present a comprehensive geochemical record of the MECO from the Escanilla Formation, a fluvial sedimentary succession in the southern Pyrenees, Spain, based on a suite of sampled paleosols, fluvial stromatolites, and pedogenic nodules. Our multiproxy approach involves using carbon and oxygen stable isotope compositions to identify the regional preservation of the MECO, calculate chemical weathering intensity and mean annual precipitation, perform clumped isotopes on carbonates, and identify clay mineralogy assemblages of paleosols. Results indicate that the Middle Eocene interval in the southern Pyrenees was characterized by low weathering rates under warm and arid climatic conditions. This is further supported by the presence of smectite, palygorskite, illite, and chlorite, which suggest seasonal rainfall but under generally dry conditions resulting in weak chemical weathering. Importantly, a negative organic carbon isotopic excursion indicates the regional, terrestrial impact of the MECO, highlighting that fluvial sedimentary successions even in active foreland basins can represent particularly interesting terrestrial archives of past changes in global climate. [ABSTRACT FROM AUTHOR]

Published
2024
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45. Trace Element and Sulfur Isotope Signatures of Volcanogenic Massive Sulfide (VMS) Mineralization: A Case Study from the Sunnhordland Area in SW Norway.

Author

Strmic Palinkas, Sabina, Fjellet, Trond, Stubseid, Håvard Hallås, Liu, Xuan, Spangenberg, Jorge Enrique, Čobić, Andrea, and Pedersen, Rolf Birger

Subjects
SULFUR isotopes, MINERALIZATION, SULFIDES, PYRRHOTITE, TRACE elements, COPPER
Abstract

The Sunnhordland area in SW Norway hosts more than 100 known mineral occurrences, mostly of volcanogenic massive sulfide (VMS) and orogeny Au types. The VMS mineralization is hosted by plutonic, volcanic and sedimentary lithologies of the Lower Ordovician ophiolitic complexes. This study presents new trace element and δ34S data from VMS deposits hosted by gabbro and basalt of the Lykling Ophiolite Complex and organic-rich sediments of the Langevåg Group. The Alsvågen gabbro-hosted VMS mineralization exhibits a significant Cu content (1.2 to >10 wt.%), with chalcopyrite and cubanite being the main Cu-bearing minerals. The enrichment of pyrite in Co, Se, and Te and the high Se/As and Se/Tl ratios indicate elevated formation temperatures, while the high Se/S ratio indicates a contribution of magmatic volatiles. The δ34S values of the sulfide phases also support a substantial influx of magmatic sulfur. Chalcopyrite from the Alsvågen VMS mineralization shows significant enrichment in Se, Ag, Zn, Cd and In, while pyrrhotite concentrates Ni and Co. The Lindøya basalt-hosted VMS mineralization consists mainly of pyrite and pyrrhotite. Pyrite is enriched in As, Mn, Pb, Sb, V, and Tl. The δ34S values of sulfides and the Se/S ratio in pyrite suggest that sulfur was predominantly sourced from the host basalt. The Litlabø sediment-hosted VMS mineralization is also dominated by pyrite and pyrrhotite. Pyrite is enriched in As, Mn, Pb, Sb, V and Tl. The δ34S values, which range from −19.7 to −15.7 ‰ VCDT, point to the bacterial reduction of marine sulfate as the main source of sulfur. Trace element characteristics of pyrite, especially the Tl, Sb, Se, As, Co and Ni concentrations, together with their mutual ratios, provide a solid basis for distinguishing gabbro-hosted VMS mineralization from basalt- and sediment-hosted types of VMS mineralization in the study area. The distinctive trace element features of pyrite, in conjunction with its sulfur isotope signature, have been identified as a robust tool for the discrimination of gabbro-, basalt- and sediment-hosted VMS mineralization. [ABSTRACT FROM AUTHOR]

Published
2024
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