scholarly journals Supplementary material to "Interpretation of zircon corona textures from metapelitic granulites of the Ivrea-Verbano Zone, Northern Italy: Two-stage decomposition of Fe-Ti oxides"

2017 ◽  
Author(s):  
Elizaveta Kovaleva ◽  
Håkon O. Austrheim ◽  
Urs S. Klötzli
Keyword(s):  
Northern Italy ◽  
Two Stage ◽  
Ti Oxides ◽  
Supplementary Material ◽  
Metapelitic Granulites

scholarly journals Interpretation of zircon coronae textures from metapelitic granulites of the Ivrea–Verbano Zone, northern Italy: two-stage decomposition of Fe–Ti oxides

Solid Earth ◽  
2017 ◽  
Vol 8 (4) ◽  
pp. 789-804 ◽  
Author(s):  
Elizaveta Kovaleva ◽  
Håkon O. Austrheim ◽  
Urs S. Klötzli
Keyword(s):  
Host Rock ◽  
Granulite Facies ◽  
Northern Italy ◽  
Retrograde Metamorphism ◽  
Brittle Deformation ◽  
Granulite Facies Metamorphism ◽  
Fine Grained ◽  
Ti Oxides ◽  
Facies Metamorphism ◽  
Metapelitic Granulites

Abstract. In this study, we report the occurrence of zircon coronae textures in metapelitic granulites of the Ivrea–Verbano Zone. Unusual zircon textures are spatially associated with Fe–Ti oxides and occur as (1) vermicular-shaped aggregates 50–200 µm long and 5–20 µm thick and as (2) zircon coronae and fine-grained chains, hundreds of micrometers long and ≤ 1 µm thick, spatially associated with the larger zircon grains. Formation of such textures is a result of zircon precipitation during cooling after peak metamorphic conditions, which involved: (1) decomposition of Zr-rich ilmenite to Zr-bearing rutile, and formation of the vermicular-shaped zircon during retrograde metamorphism and hydration; and (2) recrystallization of Zr-bearing rutile to Zr-depleted rutile intergrown with quartz, and precipitation of the submicron-thick zircon coronae during further exhumation and cooling. We also observed hat-shaped grains that are composed of preexisting zircon overgrown by zircon coronae during stage (2). Formation of vermicular zircon (1) preceded ductile and brittle deformation of the host rock, as vermicular zircon is found both plastically and cataclastically deformed. Formation of thin zircon coronae (2) was coeval with, or immediately after, brittle deformation as coronae are found to fill fractures in the host rock. The latter is evidence of local, fluid-aided mobility of Zr. This study demonstrates that metamorphic zircon can nucleate and grow as a result of hydration reactions and mineral breakdown during cooling after granulite-facies metamorphism. Zircon coronae textures indicate metamorphic reactions in the host rock and establish the direction of the reaction front.

scholarly journals Interpretation of zircon corona textures from metapelitic granulites of the Ivrea-Verbano Zone, Northern Italy: Two-stage decomposition of Fe-Ti oxides

2017 ◽  
Author(s):  
Elizaveta Kovaleva ◽  
Håkon O. Austrheim ◽  
Urs S. Klötzli
Keyword(s):  
Host Rock ◽  
Granulite Facies ◽  
Northern Italy ◽  
Retrograde Metamorphism ◽  
Brittle Deformation ◽  
Granulite Facies Metamorphism ◽  
Fine Grained ◽  
Ti Oxides ◽  
Facies Metamorphism ◽  
Metapelitic Granulites

Abstract. In this study, we report the occurrence of zircon coronae textures in metapelitic granulites of the Ivrea-Verbano Zone. Unusual zircon textures are spatially associated with Fe-Ti oxides and occur as (1) vermicular-shaped aggregates 50–200 µm long and 5–20 µm thick, and as (2) zircon coronae and fine-grained chains, hundreds of µm long and ≤ 1 µm thick, spatially associated with the larger zircon grains. Formation of such textures is a result of zircon precipitation during cooling after peak metamorphic conditions, which involved: (1) decomposition of Zr-rich ilmenite to Zr-bearing rutile and vermicular-shaped zircon during retrograde metamorphism and hydration; (2) recrystallization of Zr-bearing rutile to Zr-depleted rutile intergrown with quartz and submicron-thick zircon coronae during further exhumation and cooling. We also observed hat-shaped grains that are composed of preexisting zircon overgrown by zircon coronae during stage (2). Formation of vermicular zircon (1) preceded ductile and brittle deformation of the host rock, as vermicular zircon is found both plastically- and cataclastically-deformed. Formation of thin zircon coronae (2) was coeval with, or immediately after brittle deformation, as coronae are found to fill fractures in the host rock. The latter is evidence of local, fluid-aided mobility of Zr. This study demonstrates that metamorphic zircon can nucleate and grow as a result of hydration reactions and mineral breakdown during cooling after granulite-facies metamorphism. Zircon corona textures indicate metamorphic reactions in the host rock, and establishing the direction of the reaction front.

scholarly journals Supplementary material to "High resolution satellite products improve hydrological modeling in northern Italy"

2021 ◽  
Author(s):  
Lorenzo Alfieri ◽  
Francesco Avanzi ◽  
Fabio Delogu ◽  
Simone Gabellani ◽  
Giulia Bruno ◽  
...  
Keyword(s):  
High Resolution ◽  
Hydrological Modeling ◽  
Northern Italy ◽  
Supplementary Material

Origin of Fe-Ni-Cu (Co) sulfide and Fe-Ti oxide minerals in the c. 1.77 Ga dolerite dyke, Singhbhum Craton (eastern India)

2021 ◽  
pp. SP518-2021-46
Author(s):  
Arnab Dey ◽  
Sisir K. Mondal
Keyword(s):  
Dyke Swarm ◽  
Sulfide Liquid ◽  
Eastern India ◽  
Content Type ◽  
Dolerite Dyke ◽  
Singhbhum Craton ◽  
Ti Oxides ◽  
Supplementary Material ◽  
Oxide Minerals ◽  
Dyke Swarms

AbstractDolerite dyke swarms are widespread within the Singhbhum Craton (eastern India) that emplaced from the Neoarchean to Paleoproterozoic era just after the stabilization of crust before c. 3 Ga. These dyke swarms are oriented in NE - SW to NNE - SSW, NW - SE to WNW - ESE, E - W, and N - S directions. The WNW - ESE trending c. 1.77 Ga Pipilia dyke swarm is sampled from the Satkosia area of the Orissa state. The dyke shows a noticeable disparity in terms of the modal proportion and grain size of pyroxenes, plagioclase, Fe-Ti-oxide minerals and texture across the trend. At places the primary silicates are altered to secondary hydrated mineral assemblages of amphibole, chlorite and sericite. Primary silicates are clinopyroxene (augite: Mg# = 65.7 - 82.6; En37-48Fs11-17Wo36-41), orthopyroxene (clinoenstatite: Mg# = 68.5 − 78; En63-70Fs20-29Wo4-5), plagioclase (An11-39Ab44-82Or1-7) and Fe-Ti oxides are titanomagnetite (FeO = 34.38 − 39.50 wt%, Fe2O3 = 48.26 − 56.21 wt%, TiO2 = 5.05 − 9.60 wt%) and ilmenite (FeO = 40.75 − 43.79 wt%, Fe2O3 = 3.54 − 10.03 wt%, TiO2 = 47.82 − 50.87 wt%). Application of two-pyroxene thermometry yields an equilibration temperature range of 1065oC to 978oC, and coexisting titanomagnetite-ilmenite pairs reveal 731.39oC to 573.37oC at the oxygen fugacity (fO2) condition NNO+0.3 to FMQ-1.03. The dyke contains disseminated sulfides at the interstices of Fe-Ti-oxides, and silicates. Major sulfide minerals are pyrite, chalcopyrite, and vaesite; Pyrite-vaesite assemblages occur in association with secondary silicate minerals. Pyrite grains contain variable concentration of Co = 0.01 − 5.70 wt% and Ni = 0.02 − 1.95 wt%. Coexisting vaesite contains Co = 2.42 − 10.44 wt%, Ni = 26.40 − 47.88 wt%, and Fe = 7.32 − 26.55 wt%. Texture, sulfide-silicate assemblage, and presence of low metal/S sulfides such as the pyrite-vaesite assemblage indicate primary Fe-Ni- sulfides (pyrrhotite-pentlandite) that segregated from immiscible sulfide liquid at high temperature is modified by late magmatic/hydrothermal fluid activities. Numerous sulfide-bearing deposits hosted in ultramafic-mafic intrusions of Paleoproterozoic age have been recorded globally and the occurrence of Fe-Ni-sulfides in the c. 1.77 Ga Pipilia dyke swarm in the Singhbhum Craton enhances the exploration potential of this craton in eastern India.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5643989

scholarly journals Supplementary material to "Impacts of the COVID-19 lockdown on air pollution at regional and urban background sites in northern Italy"

2020 ◽  
Author(s):  
Jean-Philippe Putaud ◽  
Luca Pozzoli ◽  
Enrico Pisoni ◽  
Sebastiao Martins Dos Santos ◽  
Friedrich Lagler ◽  
...  
Keyword(s):  
Air Pollution ◽  
Northern Italy ◽  
Urban Background ◽  
Supplementary Material

scholarly journals Interpretation of zircon corona textures from metapelitic granulites of Ivrea-Verbano Zone, Northern Italy: Two-stage decomposition of Fe-Ti oxides

2016 ◽  
Author(s):  
Elizaveta Kovaleva ◽  
Håkon Austrheim ◽  
Urs Klötzli
Keyword(s):  
Host Rock ◽  
Oxide Phase ◽  
Granulite Facies ◽  
Brittle Deformation ◽  
Granulite Facies Metamorphism ◽  
Cooling Stage ◽  
Fine Grain ◽  
Ti Oxides ◽  
Two Stages ◽  
Metapelitic Granulites

Abstract. In this study we report the occurrence of zircon corona textures in metapelitic granulites of the Ivrea-Verbano Zone. Unusual zircon textures are spatially associated with Fe-Ti oxides and occur as (1) vermicular-shaped aggregates 50–200 µm long and 5–20 µm thick, and as (2) zircon coronas and fine-grain chains, hundreds of µm long and ≤ 1 µm thick, spatially associated with (1). Formation of such textures is a result of mineral-fluid reactions, which occurred in two stages and involved: (1) decomposition of ilmenite to Zr-rich rutile and vermicular-shaped zircon during peak metamorphism and initial cooling stage, and (2) recrystallization of Zr-rich rutile to Zr-depleted rutile and submicron-thick zircon coronas during further exhumation and cooling. We also observed hat-shaped grains that are composed of preexisting zircon overgrown by zircon coronas during stage (2). Hat-shaped grains have a flat surface towards the oxide phase, which indicates partial dissolution of preexisting zircon grain. Formation of vermicular zircon (1) preceded ductile and brittle deformation of the host rock, as vermicular zircon is found both plastically- and cataclastically-deformed. Formation of thin zircon coronas (2) was coeval with or soon after the brittle deformation, as coronas occasionally fill fractures in the host rock. Occurrences of zircon coronas has important implications in fundamental studies regarding metamorphism, metasomatism and element transport in the Earth’s crust. We demonstrate that metamorphic zircon can nucleate and grow as a result of hydration reactions at the cooling stage after granulite-facies metamorphism, and reflects stages of rock evolution. Zircon corona textures are the tool for indicating metamorphic and metasomatic reactions in the host rock, and establish the directions of the reaction front.

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