The Experts below are selected from a list of 666 Experts worldwide ranked by ideXlab platform
A F A Marques - One of the best experts on this subject based on the ideXlab platform.
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sulfide mineralization in an ultramafic rock hosted seafloor hydrothermal system from serpentinization to the formation of cu zn co rich massive sulfides
Marine Geology, 2007Co-Authors: A F A Marques, Fernando J A S Barriga, Steven D ScottAbstract:Abstract The Rainbow vent field is an ultramafic rock-hosted seafloor hydrothermal system located on the Mid-Atlantic ridge issuing high temperature, acidic, metal-rich fluids. Hydrothermal products include Cu–Zn–(Co)-rich massive sulfides with characteristics comparable to those found in mafic volcanic-hosted massive sulfide deposits. Petrography, mineralogy and geochemistry of nonmineralized and mineralized rocks sampled in the Rainbow vent field indicate that serpentinized peridotites host the hydrothermal vent system but serpentinization reactions occurred prior to and independently of the sulfide mineralization event. The onset of sulfide mineralization is reflected by extensive textural and chemical transformations in the Serpentine-Group minerals that show clear signs of hydrothermal corrosion. Element remobilization is a recurrent process in the Rainbow vent field rocks and, during simple peridotite serpentinization, Ni and Cr present in olivine and pyroxene are incorporated in the pseudomorphic Serpentine mesh and bastite, respectively. Ni is later remobilized from pseudomorphic Serpentine into the newly formed sulfides as a result of extensive hydrothermal alteration. Bulk-rock geochemistry and correlation coefficients discriminate the different processes: serpentinization, sulfide mineralization and superficial seafloor low-temperature processes related to the circulation of seawater (e.g. carbonatization, sulfide oxidation and B and U uptake).
Stéphane Guillot - One of the best experts on this subject based on the ideXlab platform.
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Serpentinites: Essential Roles in Geodynamics, Arc Volcanism, Sustainable Development, and the Origin of Life
Elements, 2013Co-Authors: Stéphane Guillot, Keiko HattoriAbstract:Serpentinites are rocks consisting mostly of the Serpentine-Group minerals chrysotile, lizardite and antigorite. They are formed by the hydration of olivine-rich ultramafic rocks and they contain up to ~13 wt% H 2 O. They have long been used by many cultures as building and carving stones. Serp entinites play essential roles in numerous geological settings. They act as a lubricant along plate boundaries during aseismic creep and contribute to the geochemical cycle of subduction zones. In the mantle, they are a reservoir of water and fluid-mobile elements. Serpentinites can produce nickel ore where weathered, and they can sequester CO 2 where carbonated. They may have provided an environment for the abiotic generation of amino acids on the early Earth and other planets, potentially leading to the development of life.
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Rheology and tectonic significance of serpentinite
Elements, 2013Co-Authors: Greg Hirth, Stéphane GuillotAbstract:Serpentinites occur in many active geologic settings and control the rheology of the lithosphere where aqueous fluids interact with ultramafic rocks. The crystal structure of Serpentine-Group minerals results in diagnostic physical properties that are important for interpreting a wide range of geophysical data and impart unique rheological behaviors. Serpentinites play an important role during continental rifting and oceanic spreading, in strain localization along lithospheric strike-slip faults, and in subduction zone processes. The rheology of Serpentine is key for understanding the nucleation and propagation of earthquakes, and the relative weakness of serpentinite can significantly affect geodynamic processes at tectonic plate boundaries.
Steven D Scott - One of the best experts on this subject based on the ideXlab platform.
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sulfide mineralization in an ultramafic rock hosted seafloor hydrothermal system from serpentinization to the formation of cu zn co rich massive sulfides
Marine Geology, 2007Co-Authors: A F A Marques, Fernando J A S Barriga, Steven D ScottAbstract:Abstract The Rainbow vent field is an ultramafic rock-hosted seafloor hydrothermal system located on the Mid-Atlantic ridge issuing high temperature, acidic, metal-rich fluids. Hydrothermal products include Cu–Zn–(Co)-rich massive sulfides with characteristics comparable to those found in mafic volcanic-hosted massive sulfide deposits. Petrography, mineralogy and geochemistry of nonmineralized and mineralized rocks sampled in the Rainbow vent field indicate that serpentinized peridotites host the hydrothermal vent system but serpentinization reactions occurred prior to and independently of the sulfide mineralization event. The onset of sulfide mineralization is reflected by extensive textural and chemical transformations in the Serpentine-Group minerals that show clear signs of hydrothermal corrosion. Element remobilization is a recurrent process in the Rainbow vent field rocks and, during simple peridotite serpentinization, Ni and Cr present in olivine and pyroxene are incorporated in the pseudomorphic Serpentine mesh and bastite, respectively. Ni is later remobilized from pseudomorphic Serpentine into the newly formed sulfides as a result of extensive hydrothermal alteration. Bulk-rock geochemistry and correlation coefficients discriminate the different processes: serpentinization, sulfide mineralization and superficial seafloor low-temperature processes related to the circulation of seawater (e.g. carbonatization, sulfide oxidation and B and U uptake).
Mongelli Giovanni - One of the best experts on this subject based on the ideXlab platform.
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An Integrated Study of the Serpentinite‐Hosted Hydrothermal System in the Pollino Massif (Southern Apennines, Italy)
'MDPI AG', 2020Co-Authors: Rizzo Giovanna, Carmela Dichicco Maria, Castiñeiras Pedro, Grassa Fausto, Laurita Salvatore, Paternoster Michele, Sinisi Rosa, Mongelli GiovanniAbstract:A comprehensive study of the serpentinite and associated veins belonging to the Frido Unit in the Pollino Massif (southern Italy) is presented here with the aim to provide new constraints about the hydrothermal system hosted by the accretionary wedge of the southern Apennines. The studied serpentinites are from two different sites: Fosso Arcangelo and Pietrapica. In both sites, the rocks show myloniticcataclastic structures and pseudomorphic and patch textures and are traversing by pervasive carbonate and quartz‐carbonate veins. The mineralogical assemblage of serpentinites consists of Serpentine Group minerals (with a predominance of lizardite), amphiboles, pyroxene, chlorite, titanite, magnetite, and talc. In some samples, hydro‐garnet was also detected and documented here for the first time. As for cutting veins, different mineralogical compositions were observed in the two sites: calcite characterizes the veins from Fosso Arcangelo, whereas quartz and dolomite are the principal minerals of the Pietrapica veins infill, suggesting a different composition of mineralizing fluids. Stable isotopes of C and O also indicate such a different chemistry. In detail, samples from the Pietrapica site are characterized by δ13C fluctuations coupled with a δ18O shift documenting calcite formation in an open‐system where mixing between deep and shallow fluids occurred. Conversely, δ13C and δ18O of the Fosso Arcangelo veins show a decarbonation trend, suggesting their developing in a closed‐system at deeper crustal conditions. Precipitation temperature calculated for both sites indicates a similar range (80 °C to 120 °C), thus suggesting carbonate precipitation within the same thermal system
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An Integrated Study of the Serpentinite-Hosted Hydrothermal System in the Pollino Massif (Southern Apennines, Italy)
'MDPI AG', 2020Co-Authors: Rizzo Giovanna, Grassa Fausto, Laurita Salvatore, Paternoster Michele, Sinisi Rosa, Dichicco, Maria Carmela, Castiñeiras García Pedro, Mongelli GiovanniAbstract:A comprehensive study of the serpentinite and associated veins belonging to the Frido Unit in the Pollino Massif (southern Italy) is presented here with the aim to provide new constraints about the hydrothermal system hosted by the accretionary wedge of the southern Apennines. The studied serpentinites are from two different sites: Fosso Arcangelo and Pietrapica. In both sites, the rocks show mylonitic-cataclastic structures and pseudomorphic and patch textures and are traversing by pervasive carbonate and quartz-carbonate veins. The mineralogical assemblage of serpentinites consists of Serpentine Group minerals (with a predominance of lizardite), amphiboles, pyroxene, chlorite, titanite, magnetite, and talc. In some samples, hydro-garnet was also detected and documented here for the first time. As for cutting veins, different mineralogical compositions were observed in the two sites: calcite characterizes the veins from Fosso Arcangelo, whereas quartz and dolomite are the principal minerals of the Pietrapica veins infill, suggesting a different composition of mineralizing fluids. Stable isotopes of C and O also indicate such a different chemistry. In detail, samples from the Pietrapica site are characterized by δ13C fluctuations coupled with a δ18O shift documenting calcite formation in an open-system where mixing between deep and shallow fluids occurred. Conversely, δ13C and δ18O of the Fosso Arcangelo veins show a decarbonation trend, suggesting their developing in a closed-system at deeper crustal conditions. Precipitation temperature calculated for both sites indicates a similar range (80 °C to 120 °C), thus suggesting carbonate precipitation within the same thermal system
Greg Hirth - One of the best experts on this subject based on the ideXlab platform.
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Rheology and tectonic significance of serpentinite
Elements, 2013Co-Authors: Greg Hirth, Stéphane GuillotAbstract:Serpentinites occur in many active geologic settings and control the rheology of the lithosphere where aqueous fluids interact with ultramafic rocks. The crystal structure of Serpentine-Group minerals results in diagnostic physical properties that are important for interpreting a wide range of geophysical data and impart unique rheological behaviors. Serpentinites play an important role during continental rifting and oceanic spreading, in strain localization along lithospheric strike-slip faults, and in subduction zone processes. The rheology of Serpentine is key for understanding the nucleation and propagation of earthquakes, and the relative weakness of serpentinite can significantly affect geodynamic processes at tectonic plate boundaries.
