Blar i forfatter "Neufeld, Kai"

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    • Evolution in H2O contents during deformation of polycrystalline quartz: An experimental study 

      Palazzin, Giulia; Raimbourg, Hugues; Stunitz, Holger; Heilbronner, Renée; Neufeld, Kai; Précigout, Jacques (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-15)
      Shear experiments were performed in a Griggs-type apparatus at 800 °C and 1.5 GPa, at a strain rate of 2.1 × 10<sup>−5</sup>s<sup>−1</sup> using different starting materials: (i) Powder (grain size 6–10 μm) of dry Brazil quartz with 0.15 wt% added H<sub>2</sub>O, (ii) “dry” Brazil quartz porphyroclasts (grain size ∼100–200 μm), devoid of fluid inclusions embedded in the same fine grained powder, and ...

    • Evolution of metal-bearing fluids at the Nussir and Ulveryggen sediment-hosted Cu deposits, Repparfjord Tectonic Window, northern Norway 

      Mun, Yulia; Strmic Palinkas, Sabina; Kullerud, Kåre; Nilsen, Kjell S.; Neufeld, Kai; Bekker, Andrey (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-13)
      The Palaeoproterozoic greenstone belts of Fennoscandia are metamorphosed and deformed volcanic and sedimentary rocks that formed in basins with a high base-metal ore potential. One of these, the Repparfjord Tectonic Window (RTW), is exposed in the Caledonides of northern Norway and contains several sediment-hosted Cu deposits including Nussir and Ulveryggen. The RTW is composed of mafic metavolcanic ...

    • Experimental grain growth of quartz aggregates under wet conditions and its application to deformation in nature 

      Fukuda, Junichi; Raimbourg, Hugues; Shimizu, Ichiko; Neufeld, Kai; Stünitz, Holger (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-05-13)
      Grain growth of quartz was investigated using two quartz samples (powder and novaculite) with water under pressure and temperature conditions of 1.0–2.5 GPa and 800–1100 ∘C. The compacted powder preserved a substantial porosity, which caused a slower grain growth than in the novaculite. We assumed a grain growth law of <i>d<sup>n</sup>−d<sup>n</sup><sub>0</sub>=k</i><sub>0</sub><i>f<sup>r</sup><su ...

    • Novel biomineralization strategy in calcareous foraminifera 

      Borrelli, Chiara; Panieri, Giuliana; Dahl, Trine Merete; Neufeld, Kai (Journal article; Tidsskriftartikkel; Peer reviewed, 2018)
      This work shows that calcareous benthic foraminifera are capable of agglutinating sedimentary particles also. In particular, we focus on Melonis barleeanus. Traditionally considered a calcareous species, our data revealed the presence of minute (~3 μm) sedimentary particles (silicate grains) inside the chamber walls of the examined shells. These particles were arranged in a definitive and systematic ...

    • The Role of Magmatic and Hydrothermal Fluids in the Formation of the Sasa Pb-Zn-Ag Skarn Deposit, Republic of Macedonia 

      Strmic Palinkas, Sabina; Peltekovski, Zlatko; Tasev, Goran; Serafimovski, Todor; Šmajgl, Danijela; Rajic, Kristijan; Spangenberg, Jorge; Neufeld, Kai; Palinkaš, Ladislav A. (Journal article; Peer reviewed, 2018-11-29)
      The Sasa Pb-Zn-Ag deposit belongs to the group of distal base metal skarn deposits. The deposit is located within the Serbo-Macedonian massif, a metamorphosed crystalline terrain of Precambrian to Paleozoic age. The mineralization, hosted by Paleozoic marbles, shows a strong lithological control. It is spatially and temporally associated with the calc-alkaline to shoshonitic post-collisional magmatism ...

    • Stability of Cu-Sulfides in Submarine Tailing Disposals: A Case Study from Repparfjorden, Northern Norway 

      Mun, Yulia; Strmic Palinkas, Sabina; Forwick, Matthias; Junttila, Juho; Pedersen, Kristine Bondo; Sternal, Beata; Neufeld, Kai; Tibljaš, Darko; Kullerud, Kåre (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-13)
      Mine tailings that were produced during the exploitation of the Ulveryggen siliciclastic sediment-hosted Cu deposit in northern Norway were disposed into the inner part of Repparfjorden from 1972 to 1978/1979. This study focuses on the mineralogy and geochemistry of the submarine mine tailings and underlying natural marine sediments from the inner part of Repparfjorden, as well as on the primary ...

    • Transformation weakening: Diffusion creep in eclogites as a result of interaction of mineral reactions and deformation 

      Stunitz, Holger; Neufeld, Kai; Heilbronner, Renée; Finstad, Ane Kongsro; Konopásek, Jiří; Mackenzie, James R. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-07-09)
      The deformation of eclogites and the driving forces for their fabric development are an important topic, potentially allowing to determine deformation rates and stresses in subduction zones, where the greatest number of large earthquakes occurs. Here, fabric studies of grain size and shape, texture, and chemical composition from two locations of Variscan and Alpine eclogites are presented. All samples ...