The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
M. Zucali - One of the best experts on this subject based on the ideXlab platform.
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Strain partitioning in Host Rock controls light rare earth element release from allanite-(Ce) in subduction zones
Mineralogical Magazine, 2020Co-Authors: L. Corti, D. Zanoni, G.d. Gatta, M. ZucaliAbstract:AbstractCombined microstructural, mineral chemical, X-ray maps and X-ray single-crystal diffraction analyses are used to reveal the behaviour of individual grains of magmatic allanite relicts Hosted in variably deformed metagranitoids at Lago della Vecchia (inner part of the Sesia-Lanzo Zone, Western Alps, Europe), which experienced high-pressure and low-temperature metamorphism during the Alpine subduction. X-ray single-crystal diffraction shows that none of the allanite crystals, irrespective of the strain state of the Host Rock, record any evidence of plastic deformation (i.e. intracrystalline deformation), as indicated by the shape of the Bragg diffraction spots, the atomic site positions, and their displacement around the centre of gravity. On the contrary, strong plastic deformation affected matrix minerals, such as quartz, white mica and feldspar of the Hosting Rocks, during the development of the Alpine eclogitic- and blueschist-facies metamorphism. Despite the strain-free atomic structures of allanite, different patterns of chemical zoning, as a function of strain accumulated in the Rock matrix, are observed. As allanite occurs in magmatic and metamorphic Rocks and it is stable at high-pressure and low-temperature conditions, we infer that allanite could behave as one of the main carriers of light rare earth elements into the mantle wedge during subduction of continental crust. In particular, the release of light rare earth elements from allanite, under high-pressure conditions in subduction zones, is facilitated by high strain accumulated in the Host Rock.
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Strain partitioning in Host Rock controls LREE release from allanite-(Ce) in subduction zones
'Mineralogical Society', 2020Co-Authors: L. Corti, D. Zanoni, G.d. Gatta, M. ZucaliAbstract:Combined microstructural, mineral chemical, X-ray maps, and X-ray single-crystal diffraction analyses are used to reveal the rheological behaviour of individual grains of magmatic allanite relicts Hosted in variably deformed metagranitoids at Lago della Vecchia (inner part of the Sesia-Lanzo Zone, Western Alps, Europe), which experienced high pressure and low temperature metamorphism during the Alpine subduction. X-ray single crystal diffraction shows that none of the allanite crystals, irrespective of the strain state of the Host Rock, record any evidence of plastic deformation (i.e., intracrystalline deformation), as indicated by the shape of the Bragg diffraction spots, the atomic site positions, and their displacement around the centre of gravity. On the contrary, strong plastic deformation affected matrix minerals, such as quartz, white mica, and feldspar of the Hosting Rocks, during the development of the Alpine eclogitic- and blueschist-facies metamorphism. Despite the strain-free atomic structures of allanite, different patterns of chemical zoning, as a function of strain accumulated in the Rock matrix, are observed. Since allanite occurs in magmatic and metamorphic Rocks and it is stable at high pressure and low temperature conditions, we infer that allanite could behave as one of the main carriers of light-rare-earth-elements into the mantle wedge during subduction of continental crust. In particular, the release of light-rare-earth-elements from allanite, under high pressure conditions in subduction zones, is facilitated by high strain accumulated in the Host Rock
Z. Wang - One of the best experts on this subject based on the ideXlab platform.
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Hydro-geochemical analysis of the interplay between the groundwater, Host Rock and water curtain system for an underground oil storage facility
Tunnelling and Underground Space Technology, 2018Co-Authors: Z. Wang, Y. Glais, L. Qiao, A. Huang, J. LiuAbstract:Hydro-geochemical analysis was performed to investigate the interplay between the groundwater, Host Rock and water curtain system for the start-up of a pilot underground oil storage facility in China. 54 groundwater samples were collected and analyzed to obtain the characteristics of the hydro-geochemical environment evolution for the start-up period. The groundwater-Rock mass interaction was studied with comparing the changes in the ion concentrations, pH values and total dissolved solid concentrations in the groundwater and a mineralogical analysis of the Host Rock. The groundwater-water curtain system interaction was identified using statistical analysis of the similarity in chemical contents in the groundwater samples. A mixing calculation was performed to evaluate the mixing ratios of the water curtain system, background water and oil/vapor in the seepage water into the storage caverns. It was concluded that calcium carbonate equilibrium is the predominant chemical reaction. The 54 groundwater samples could be classified into 5 clusters. Among the 5 clusters, there is one cluster showing that the tap water injected to the water curtain system is similar in chemical contents to those in the monitoring boreholes around the facility, which confirms the efficiency of the water curtain system for the start-up of the facility. It was found that the two dominant factors influencing the evolution of groundwater chemical content were Host Rock dissolution and groundwater seepage. Most of seepage water was originated from oil/vapor and water curtain system while the percentage from the background water was almost zero in the start-up period of the facility. © 2017 Elsevier Ltd
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hydro geochemical analysis of the interplay between the groundwater Host Rock and water curtain system for an underground oil storage facility
Tunnelling and Underground Space Technology, 2018Co-Authors: Z. Wang, Y. Glais, L. Qiao, A. HuangAbstract:Abstract Hydro-geochemical analysis was performed to investigate the interplay between the groundwater, Host Rock and water curtain system for the start-up of a pilot underground oil storage facility in China. 54 groundwater samples were collected and analyzed to obtain the characteristics of the hydro-geochemical environment evolution for the start-up period. The groundwater-Rock mass interaction was studied with comparing the changes in the ion concentrations, pH values and total dissolved solid concentrations in the groundwater and a mineralogical analysis of the Host Rock. The groundwater-water curtain system interaction was identified using statistical analysis of the similarity in chemical contents in the groundwater samples. A mixing calculation was performed to evaluate the mixing ratios of the water curtain system, background water and oil/vapor in the seepage water into the storage caverns. It was concluded that calcium carbonate equilibrium is the predominant chemical reaction. The 54 groundwater samples could be classified into 5 clusters. Among the 5 clusters, there is one cluster showing that the tap water injected to the water curtain system is similar in chemical contents to those in the monitoring boreholes around the facility, which confirms the efficiency of the water curtain system for the start-up of the facility. It was found that the two dominant factors influencing the evolution of groundwater chemical content were Host Rock dissolution and groundwater seepage. Most of seepage water was originated from oil/vapor and water curtain system while the percentage from the background water was almost zero in the start-up period of the facility.
Thierry Reuschle - One of the best experts on this subject based on the ideXlab platform.
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physical and mechanical property relationships of a shallow intrusion and volcanic Host Rock pinnacle ridge mt ruapehu new zealand
Journal of Volcanology and Geothermal Research, 2018Co-Authors: S P Mordensky, M C Villeneuve, Ben Kennedy, Michael J Heap, D M Gravley, Jamie Farquharson, Thierry ReuschleAbstract:Abstract Shallow magmatic intrusions are prevalent in volcanic settings worldwide. Understanding how these intrusions interact and influence their volcanic Host Rocks is therefore relevant to many engineering geology, geothermal, and volcanological applications. In this study, we present the most comprehensive dataset for a shallow intrusion and its Host Rock in a volcanic setting to date, detailing the mechanical and physical properties of volcanic Rocks from Pinnacle Ridge, Mt. Ruapehu, New Zealand. Based on the geomechanical properties of 194 measured samples, we identify seven geotechnical units: (1) unaltered dense coherent lava, (2) altered dense coherent lava, (3) unaltered brecciated lava margin, (4) altered brecciated lava margin, (5) unaltered intrusion, (6) altered intrusion, and (7) hydrothermal veining. We detail the mineralogy (andesite compositions ranging from primary to an advanced argillic alteration assemblage), porosity (0.7–31%), permeability (10−21–10−12 m2), elastic wave velocities (1994–5615 m/s), uniaxial compressive strength (1–332 MPa) of these geotechnical units. Our laboratory analyses indicate that primary lithology is the predominant control on the physical and mechanical properties of the geotechnical units. Additionally, the data suggest that there is a correlation between distance to the largest intrusion; this is particularly evident for the measurements on the brecciated lava margin samples. Towards the largest intrusion, this breccia shows decreasing porosity (30.92 to 5.49%) and permeability (10−12 to 10−17 m2) and increasing elastic wave velocities (1994 to 4157 m/s) and uniaxial compressive strength (3 to 61 MPa). Thin-section analysis suggests that these correlations are due to mineral precipitation within fractures and pores in the brecciated lava margins. These correlations with distance to the largest intrusion are not shared by the altered intrusions or dense coherent lavas. We suggest that the high primary permeability of the unaltered breccia facilitated efficient hydrothermal fluid circulation and mineral precipitation adjacent to the intrusion. The other geotechnical units are less affected because hydrothermal fluid flow, alteration, and mineral precipitation were limited due to low initial permeability (10−21–10−16 m2). Our study shows that the initial properties of the Host Rock (i.e. porosity and permeability) control the extent of hydrothermal alteration and the susceptibility to modifications of Rock geomechanical properties. Modifications to porosity and permeability can influence edifice-scale behaviour; for example, a reduction in permeability can result in pore pressure augmentation, which exerts a primary control on volcanic slope stability, seismicity, and eruptive behaviour. This study provides the most comprehensive and complete geomechanical properties data suite on a shallow intrusion in volcanic Host Rock to date and will support monitoring and modelling of volcanic hazards associated with shallow igneous intrusions.
Helene Brätz - One of the best experts on this subject based on the ideXlab platform.
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Host Rock compositional controls on zircon trace element signatures in metabasites from the Austroalpine basement
Geochimica et Cosmochimica Acta, 2006Co-Authors: Bernhard Schulz, Reiner Klemd, Helene BrätzAbstract:Zircon populations of Neoproterozoic and early Paleozoic age occur in metabasites of a high-pressure amphibolite-facies unit of the Austroalpine basement south of the Tauern Window. The Host Rocks for these zircons are eclogitic amphibolites of N-MORB-type character, hornblende gneisses with volcanic-arc basalt signature, and alkaline within-plate-basalt amphibolites. Bulk Rock magmatic trace element patterns were preserved during amphibolite-facies high-pressure and subsequent high-temperature events, as well as a greenschist-facies overprint. Positive Ce and negative Eu anomalies and enrichment of HREE in normalized zircon REE patterns, as analysed by LA-ICP-MS, are typical for an igneous origin of these zircon suites. Zircon Y is well correlated to HREE, Ce, Th, U, Nb, and Ta and allows discrimination of compositional fields for each Host Rock type. Low Th/U ratios are correlated to low Y and HREE abundances in zircon from low bulk Th/U Host Rocks. This is likely a primary igneous characteristic that cannot be attributed to metamorphic recrystallization. Variations of zircon/Host Rock element ratios confirm that ionic radii and charges control abundances of many trace elements in zircon. The trace element ratios—presented as mineral/melt distribution coefficients—indicate a selectively inhibited substitution of Zr and Si by HREE and Y in zircon which crystallized from a N-MORB melt. Correlated Host Rock and zircon trace element concentrations indicate that the metabasite zircons are not xenocrysts but crystallized from mafic melts, represented by the actual Host Rocks.
David R Gray - One of the best experts on this subject based on the ideXlab platform.
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the importance of diffusion advection and Host Rock lithology on vein formation a stable isotope study from the paleozoic ouachita orogenic belt arkansas and oklahoma
Geological Society of America Bulletin, 2002Co-Authors: Ian J Richards, Jeffrey B Connelly, Robert T Gregory, David R GrayAbstract:More than 600 stable isotope analyses from veins and their metasedimentary Host Rocks from the Ouachita orogenic belt of Arkansas and Oklahoma provide an opportunity to study fluid-Rock interaction processes associated with vein formation during deformation and low-grade regional metamorphism. The δ18O values of vein quartz vary from 16.0 to 26.4‰, whereas coexisting Host Rocks have a greater range from 12.9 to 27.4‰. The oxygen isotopic compositions of quartz vein versus those of the coexisting Host Rocks follow an array described by δ18Ovein quartz ≈ δ18Owhole Rock + e, where e ≈ 8–0.3(δ18Owhole Rock). This relationship emphasizes the dependence of δ18O values of vein quartz on Host-Rock oxygen isotopic composition. The e term empirically monitors the difference between the quartz-water fractionation factor and the compositional dependence of the bulk-Rock–water fractionation factor. Vein-quartz–Host-Rock Δ18O fractionations are ∼0‰ in chert, novaculite, quartzite, and siliceous shale and typically between 1 and 4‰ in sandstones and shales. In quartzite and sandstone units that are bounded by shales and associated with significant quartz-crystal deposits, vein-quartz–Host-Rock fractionations are often unusually large, near 7‰. Quartz-calcite oxygen isotope geothermometry indicates that veins from the Ouachita Mountains formed over a temperature interval of 100 °C, consistent with fluid-inclusion temperatures previously obtained from quartz crystals. Individual quartz veins are homogeneous, with <0.4‰ variation, for all vein orientations at all scales, even though vein formation occurred over a temperature interval in which quartz-water fractionation varies by 5‰. This homogeneity highlights the insensitivity of vein-quartz δ18O values to temperature when veins form under Rock-buffered conditions. The similarity between vein and Host-Rock δ18O values in quartz-rich lithologies, and between vein and Host-Rock δ13C values in calcite-bearing Rocks, indicates that diffusion was an important mass-transport mechanism. The variability in δ18O values between calcite-bearing veins and Host Rocks and large vein-quartz–whole-Rock fractionations in some sandstones and quartzites indicates that advection also played a major role in mass transport associated with vein formation. This inference leads to the interpretation that veins from the Ouachita Mountains formed by a combined diffusion-advection process, whereby 18O and 13C from the Host Rock was transported into the veins with the assistance of a Rock-buffered fluid on outcrop scales of 10–100 m.
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The importance of diffusion, advection, and Host-Rock lithology on vein formation: A stable isotope study from the Paleozoic Ouachita orogenic belt, Arkansas and Oklahoma
Geological Society of America Bulletin, 2002Co-Authors: Ian J Richards, Jeffrey B Connelly, Robert T Gregory, David R GrayAbstract:More than 600 stable isotope analyses from veins and their metasedimentary Host Rocks from the Ouachita orogenic belt of Arkansas and Oklahoma provide an opportunity to study fluid-Rock interaction processes associated with vein formation during deformation and low-grade regional metamorphism. The δ18O values of vein quartz vary from 16.0 to 26.4‰, whereas coexisting Host Rocks have a greater range from 12.9 to 27.4‰. The oxygen isotopic compositions of quartz vein versus those of the coexisting Host Rocks follow an array described by δ18Ovein quartz ≈ δ18Owhole Rock + e, where e ≈ 8–0.3(δ18Owhole Rock). This relationship emphasizes the dependence of δ18O values of vein quartz on Host-Rock oxygen isotopic composition. The e term empirically monitors the difference between the quartz-water fractionation factor and the compositional dependence of the bulk-Rock–water fractionation factor. Vein-quartz–Host-Rock Δ18O fractionations are ∼0‰ in chert, novaculite, quartzite, and siliceous shale and typically between 1 and 4‰ in sandstones and shales. In quartzite and sandstone units that are bounded by shales and associated with significant quartz-crystal deposits, vein-quartz–Host-Rock fractionations are often unusually large, near 7‰. Quartz-calcite oxygen isotope geothermometry indicates that veins from the Ouachita Mountains formed over a temperature interval of 100 °C, consistent with fluid-inclusion temperatures previously obtained from quartz crystals. Individual quartz veins are homogeneous, with