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1632. Multi-scale and multi-modal imaging study of mantle xenoliths and petrological implicationsMarco Venier, Luca Ziberna, Lucia Mancini, Alexander P. Kao, Federico Bernardini, Giacomo Roncoroni, Sula Milani, Nasrrddine Youbi, Yondon Majigsuren, Angelo De Min, Davide Lenaz, 2024, original scientific article Abstract: The accurate textural characterization of mantle xenoliths is one of the fundamental steps to understanding the main processes occurring in the upper mantle, such as sub-solidus recrystallization, magmatic crystallization, and metasomatism. Texture, composition, and mineralogy reflect the temperature, pressure, stress conditions, melting, and/or contamination events undergone before and during the entrapment in the host magma. For these reasons, characterizing the three-dimensional (3D) texture of silicate, oxide, sulfide, and glass phases has great importance in the study of mantle xenoliths. We performed a multi-scale and multi-modal 3D textural analysis based on X-ray computed microtomography (µ-CT) data of three mantle xenoliths from different geodynamic settings (i.e., mobile belt zone, pericraton, oceanic hotspot). The samples were selected to represent different, variably complex internal structures composed of grains of different phases, fractures, voids, and fluid inclusions of different sizes. We used an approach structured in increasing steps of spatial and contrast resolution, starting with in-house X-ray µ-CT imaging (spatial resolution from 30 µm down to 6.25 µm) and moving to high-resolution synchrotron X-ray µ-CT at the micrometer scale. We performed a 3D characterization of mantle xenoliths, comparing the results with the analysis of conventional 2D images (thin sections) obtained by optical microscopy and simulating the random sectioning of several thin sections to estimate the probability of correct modal classification. The 3D models allow the extraction of textural information that cannot be quantified solely from thin sections: spinel layering, distribution of silicic glass, and related vesicles. Moreover, high-density volumes identified as sulfides were detected in two xenoliths, showing no relation with the spinel layering in one case and a preferential concentration along fractures in the other. Given the variety of textures and mineral assemblages of mantle xenoliths worldwide, the results are used to suggest experimental and analytical protocols for the characterization of these materials.
Keywords: petrology, mantle xenoliths, X-ray microtomography, multi-scale image analysis
Published in DiRROS: 23.05.2024; Views: 340; Downloads: 71
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1633. Poročilo o preskusu št.: LVG 2024-034 : vzorec št. 2024/00084Tine Hauptman, Špela Hočevar, Zina Devetak, Barbara Piškur, 2024, expertise, arbitration decision Keywords: varstvo gozdov, morfološke analize, Euwallacea fornicatus, Neocosmospora euwallaceae, strokovne naloge IVHVVR, PCR
Published in DiRROS: 23.05.2024; Views: 336; Downloads: 147
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1634. Poročilo o preskusu št.: LVG 2024-025 : vzorec št. 2024/00062Tine Hauptman, Špela Hočevar, Barbara Piškur, 2024, expertise, arbitration decision Keywords: varstvo gozdov, morfološke analize, PP Geosmithia morbida, bolezen tisočerih rakov, rastlinski vzorec, rtPCR
Published in DiRROS: 23.05.2024; Views: 380; Downloads: 0
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1635. Poročilo o preskusu št.: LVG 2024-043 : vzorec št. 2024/00061Tine Hauptman, Špela Hočevar, Barbara Piškur, 2024, expertise, arbitration decision Keywords: varstvo gozdov, morfološke analize, program preiskav, Fusarium circinatum, Pinus, borov smolasti rak, PCR
Published in DiRROS: 23.05.2024; Views: 416; Downloads: 0
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1636. Poročilo o preskusu št.: LVG 2024-033 : vzorec št. 2024/00083Tine Hauptman, Špela Hočevar, Barbara Piškur, 2024, expertise, arbitration decision Keywords: varstvo gozdov, morfološke analize, program preiskav, Fusarium circinatum, Pinus, borov smolasti rak, PCR
Published in DiRROS: 23.05.2024; Views: 338; Downloads: 0
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1637. Increasing the amorphous content in river sediments intended for supplementary cementitious materials using flame synthesisWolfgang Wisniewski, Jozef Kraxner, Lea Žibret, Dušan Galusek, Vilma Ducman, 2024, original scientific article Abstract: Dredged river sediments are currently a waste material which is mainly landfilled or reintegrated into rivers. They can also be used as a renewable resource for the construction sector. Pre- treatments at high temperatures allow their use for more advanced applications such as supplementary cementitious materials (SCMs) or as a precursor for alkali activated materials (AAMs). The work presented here shows that flame synthesis can be used to almost completely vitrify such sediments and increase their leachability for Al and Si beyond the levels achieved by conventional calcination at 750–950 ◦C for 1h.
The reactivity of the prepared samples was analyzed via the Si and Al solubility in 10 M NaOH and was generally increased by the applied treatments but maximized by flame synthesis. Their microstructure was analyzed using scanning electron microscopy and their phase composition was monitored using X-ray diffraction. The results show an almost complete amorphization of the sediments by flame synthesis, however their reactivity does not increase at the same rate.
Keywords: sediments, SCM, vitrification, properties
Published in DiRROS: 23.05.2024; Views: 462; Downloads: 318
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1638. Poročilo o preskusu št.: LVG 2024-027 : vzorec št. 2024/00058Tine Hauptman, Špela Hočevar, Barbara Piškur, 2024, expertise, arbitration decision Keywords: varstvo gozdov, morfološke analize, program preiskav, Fusarium circinatum, Pinus, borov smolasti rak, PCR
Published in DiRROS: 23.05.2024; Views: 294; Downloads: 0
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1639. Poročilo o preskusu št.: LVG 2024-026 : vzorec št. 2024/00064Tine Hauptman, Špela Hočevar, Barbara Piškur, 2024, expertise, arbitration decision Keywords: varstvo gozdov, morfološke analize, program preiskav, Fusarium circinatum, Pinus, borov smolasti rak, PCR
Published in DiRROS: 23.05.2024; Views: 357; Downloads: 0
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