Results 81 to 90 of about 1,123,502 (206)

Petrological implications of melanite in the rocks of the Morro de São João Alkaline Complex, Casimiro de Abreu, Rio de Janeiro, Brazil [PDF]

Brazilian Journal of Geology
This article presents a study of the titanium-rich andradite garnet, melanite, which occurs in the rocks of the Morro de São João Alkaline Complex, of Paleocene age, located in the district of Casimiro de Abreu, southeast of the state of Rio de Janeiro ...
Mariana Bessa Fagundes, Anderson Santos, Mauro Geraldes, Sérgio de Castro Valente, Eliane Guedes, Theresa Rocco Pereira Barbosa, Júlio Lopes   +6 more
doaj   +1 more source

Earth’s past and present mantle oxygen fugacity

Nature Reviews Earth & Environment
Oxygen is the most abundant element in Earth’s mantle. Oxygen fugacity (fO2), which quantifies the availability of oxygen to mediate oxidation–reduction reactions, affects important mantle processes, such as depth of melting, extraction of volatiles to the atmosphere, crustal composition and ore body generation.
Elizabeth Cottrell, Dante Canil, Charles Langmuir, Katy A. Evans, Fabrice Gaillard   +4 more
openaire   +2 more sources

(Table 3) Oxygen fugacity of glasses from ODP Leg 135 basalt samples

, 1994
(Table 3) Oxygen fugacity of glasses from ODP Leg 135 basalt ...
Nilsson Farley, Kristen, Kristen Nilsson Farley (6959231)   +1 more
core   +1 more source

Oxygen Fugacity of Global Ocean Island Basalts

Geochemistry, Geophysics, Geosystems
AbstractMantle plumes contain heterogenous chemical components and sample variable depths of the mantle, enabling glimpses into the compositional structure of Earth's interior. In this study, we evaluated ocean island basalts (OIB) from nine plume locations to provide a global and systematic assessment of the relationship between fO2 and He‐Sr‐Nd‐Pb‐W ...
Lori N. Willhite, Ricardo Arevalo, Philip Piccoli, John C. Lassiter, Devin Rand, Matthew G. Jackson, James M. D. Day, Robert W. Nicklas, Marek Locmelis, Thomas J. Ireland, Igor S. Puchtel   +10 more
openaire   +2 more sources

The oxygen fugacity of olivine-phyric martian basalts and the components within the mantle and crust of Mars

, 2003
The oxygen fugacity of olivine-phyric martian basalts is estimated using olivine-pyroxene- spinel equilibria, supported by detailed petrography. Results are plotted, along with previous oxygen fugacity estimates, against La/Yb, which is used as a proxy ...
Herd, C. D. K.
core   +2 more sources

Effect of oxygen fugacity on the glass transition, viscosity and structure of silica- and iron-rich magmatic melts

, 2017
International audienceIron oxidation state affects the physical properties and structure of natural melts and, ultimately, magmatic and volcanic processes such as magma transport and eruptive style.
Danilo Di Genova, Hess, Kai-Uwe, Jérémie Vasseur, Kai-Uwe Hess, Daniel R. Neuville, Vasseur, Jérémie, Dingwell, Donald B., Donald B. Dingwell, Di Genova, Danilo, Neuville, Daniel R.   +9 more
core   +2 more sources

Origin of the RNA World in Cold Hadean Geothermal Fields Enriched in Zinc and Potassium: Abiogenesis as a Positive Fallout from the Moon-Forming Impact?

Life
The ubiquitous, evolutionarily oldest RNAs and proteins exclusively use rather rare zinc as transition metal cofactor and potassium as alkali metal cofactor, which implies their abundance in the habitats of the first organisms.
Armen Y. Mulkidjanian, Daria V. Dibrova, Andrey Y. Bychkov   +2 more
doaj   +1 more source

The speciation of carbon within eclogite rocks as function of pressure, temperature and oxygen fugacity

, 2017
The speciation of volatile elements within mantle rocks is strongly controlled by the local redox conditions buffered by the surrounding abundant Fe-bearing minerals.
DOMINIJANNI, SERENA, Vincenzo Stagno, Marco Caruso   +2 more
core  

Hydrothermal alteration of seafloor peridotites does not influence oxygen fugacity recorded by spinel oxybarometry

, 2016
Publisher's PDFOlivine, orthopyroxene, and spinel compositions within seafloor peridotites yield important information about the nature of Earth’s mantle.
Cottrell, Elizabeth, Davis, Fred A., Birner, Suzanne K., Warren, Jessica M.   +3 more
core   +1 more source

Temporal evolution of mantle wedge oxygen fugacity during subduction initiation

, 2015
Arc basalts have a higher proportion of Fe in an oxidized state (Fe^(3+)) relative to Fe^(2+) compared to mid-oceanic ridge basalts (MORBs), likely because slab-derived fluids oxidize the mantle wedge where subduction zone magmas originate. Yet, the time
Kelley, Katherine A., Brounce, Maryjo, Cottrell, Elizabeth, Reagan, Mark K.   +3 more
core   +1 more source