Results 41 to 50 of about 4,448 (271)

Evidence for life in the isotopic analysis of surface sulphates in the Haughton impact structure, and potential applications on Mars [PDF]

, 2012
The analysis of sulphur isotopic compositions in three sets of surface sulphate samples from the soil zone in the Haughton impact structure shows that they are distinct.
Izawa, M.R.M., Osinski, G.R., Boyce, A.J., Banerjee, N., Lee, P., Parnell, J., Flemming, R., Matthew, R.M.   +7 more
core   +1 more source

Nitrogen transformation pathways, rates, and isotopic signatures in Lake Lugano [PDF]

, 2014
The consequences of detrimental alterations caused to the natural nitrogen (N) cycle are manifold. To tackle problems, such as eutrophication of coastal marine and lacustrine environments, or increasing emissions of greenhouse gas nitrous oxide (N2O ...
Wenk, Christine B.
core   +1 more source

Experimental constraints on kinetic and equilibrium silicon isotope fractionation during the formation of non-biogenic chert deposits [PDF]

, 2015
Silicon isotopic compositions (δ30Si) of modern and ancient siliceous sedimentary rocks provide valuable information on conditions in depositional environments, but interpretations are hampered by the lack of experimentally validated fractionation ...
van Bergen, Manfred J., Vroon, Pieter Z., Petrology, Geilert, Sonja, van den Boorn, Sander H.J.M., Roerdink, Desiree L., van den Boorn, Sander H J M, NWO-ALW Open: Exploring the Earth's earliest oceans with silicon: magnitudes of isotopic fractionation, NWO-NSO: Testing the robustness of the sulfur stable isotope biomarker and paleoredox indicator for planetary exploration   +8 more
core   +1 more source

Multiple sulfur isotope signatures of sulfite and thiosulfate reduction by the model dissimilatory sulfate-reducer, Desulfovibrio alaskensis str. G20

Frontiers in Microbiology, 2014
Dissimilatory sulfate reduction serves as a key metabolic carbon remineralization process in anoxic marine environments. Sulfate reducing microorganisms can impart a wide range in mass-dependent sulfur isotopic fractionation.
William D. Leavitt, William D. Leavitt, Renata eCummins, Marian L Schmidt, Min Sub eSim, Min Sub eSim, Shuhei eOno, Alexander S. Bradley, David T. Johnston   +8 more
doaj   +1 more source

SQUID-SIMS is a useful approach to uncover primary signals in the Archean sulfur cycle [PDF]

, 2014
The Agouron Institute and National Aeronautic and Space Administration Exobiology Award NNX09AM91G supported this work.Many aspects of Earth's early sulfur cycle, from the origin of mass-anomalous fractionations to the degree of biological participation,
Guan, Yunbin, Woodward W. Fischer, Fike, David A., Fike, David A, Jena E. Johnson, Raub, Timothy D, David A. Fike, Fischer, Woodward W., Johnson, Jena E, Eiler, John M, Timothy D. Raub, Raub, Timothy D., Yunbin Guan, Kirschvink, Joseph L., Johnson, Jane E., Joseph L. Kirschvink, John M. Eiler, Fischer, Woodward W, Kirschvink, Joseph L, Eiler, John M.   +19 more
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Sulphur isotope geochemistry of black shale-hosted antimony mineralization, Arnsberg, northern Rhenish Massif, Germany [PDF]

, 2003
Vein-type and bedding-concordant mesothermal (180–410 °C) stibnite–sulphosalt mineralization at Arnsberg, NE Rhenish Massif, Germany, is hosted by Carboniferous pyrite-rich black shales and siliceous limestones.
Wagner, T., Boyce, A.J.
core   +1 more source

The Biogeochemical Sulfur Cycle of Marine Sediments

Frontiers in Microbiology, 2019
Microbial dissimilatory sulfate reduction to sulfide is a predominant terminal pathway of organic matter mineralization in the anoxic seabed. Chemical or microbial oxidation of the produced sulfide establishes a complex network of pathways in the sulfur ...
Bo Barker Jørgensen, Alyssa J. Findlay, André Pellerin   +2 more
doaj   +1 more source

Sulfur-controlled iron isotope fractionation experiments of core formation in planetary bodies [PDF]

, 2021
A series of high pressure and temperature experiments were conducted to better constrain the Fe isotope fractionation during core-mantle differentiation in planetesimal and planetary bodies.
Horan M.F., Kaufman L.A., Hillgren V.J., Mesa-Garcia J., Shahar A., Mock T.D.   +5 more
core   +1 more source

Sulfur degassing at Erta Ale (Ethiopia) and Masaya (Nicaragua) volcanoes: Implications for degassing processes and oxygen fugacities of basaltic systems

Geochemistry, Geophysics, Geosystems, 2013
We investigate the relationship between sulfur and oxygen fugacity at Erta Ale and Masaya volcanoes. Oxygen fugacity was assessed utilizing Fe3+/∑Fe and major element compositions measured in olivine‐hosted melt inclusions and matrix glasses.
J. M. deMoor, T. P. Fischer, Z. D. Sharp, P. L. King, M. Wilke, R. E. Botcharnikov, E. Cottrell, M. Zelenski, B. Marty, K. Klimm, C. Rivard, D. Ayalew, C. Ramirez, K. A. Kelley   +13 more
doaj   +1 more source

Deconstructing the Dissimilatory Sulfate Reduction Pathway: Isotope Fractionation of a Mutant Unable of Growth on Sulfate

Frontiers in Microbiology, 2018
The sulfur isotope record provides key insight into the history of Earth's redox conditions. A detailed understanding of the metabolisms driving this cycle, and specifically microbial sulfate reduction (MSR), is crucial for accurate paleoenvironmental ...
Emma Bertran, William D. Leavitt, William D. Leavitt, Andre Pellerin, Grant M. Zane, Judy D. Wall, Itay Halevy, Boswell A. Wing, David T. Johnston   +8 more
doaj   +1 more source