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Kristoffer Szilas - One of the best experts on this subject based on the ideXlab platform.
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Corundum formation by metasomatic reactions in Archean metapelite, SW Greenland: Exploration vectors for Ruby deposits within high-grade greenstone belts
Elsevier, 2018Co-Authors: Chris Yakymchuk, Kristoffer SzilasAbstract:Corundum (Ruby-sapphire) is known to have formed in situ within Archean metamorphic rocks at several localities in the North Atlantic Craton of Greenland. Here we present two case studies for such occurrences: (1) Maniitsoq region (Kangerdluarssuk), where kyanite paragneiss hosts Ruby corundum, and (2) Nuuk region (Storø), where sillimanite gneiss hosts Ruby corundum. At both occurrences, ultramafic rocks (amphibole-peridotite) are in direct contact with the Ruby-bearing zones, which have been transformed to mica schist by metasomatic reactions. The bulk-rock geochemistry of the Ruby-bearing rocks is consistent with significant depletion of SiO2 in combination with addition of Al2O3, MgO, K2O, Th and Sr relative to an assumed aluminous precursor metapelite. Phase equilibria modelling supports Ruby genesis from the breakdown of sillimanite and kyanite at elevated temperatures due to the removal of SiO2. The juxtaposition of relatively silica- and aluminum-rich metasedimentary rocks with low silica ultramafic rocks established a chemical potential gradient that leached/mobilized SiO2 allowing corundum to stabilize in the former rocks. Furthermore, addition of Al2O3 via a metasomatic reaction is required, because Al/Ti is fractionated between the aluminous precursor metapelites and the resulting corundum-bearing mica schist. We propose that Al was mobilized either by complexation with hydroxide at alkaline conditions, or that Al was transported as K-Al-Si-O polymers at deep crustal levels. The three main exploration vectors for corundum within Archean greenstone belts are: (1) amphibolite- to granulite-facies metamorphic conditions, (2) the juxtaposition of ultramafic rocks and aluminous metapelite, and (3) mica-rich reactions zones at their interface. Keywords: Ultramafic rocks, Kyanite, Sillimanite, Metasomatism, Pseudosection, Desilicificatio
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corundum formation by metasomatic reactions in archean metapelite sw greenland exploration vectors for Ruby deposits within high grade greenstone belts
Geoscience frontiers, 2017Co-Authors: Chris Yakymchuk, Kristoffer SzilasAbstract:Abstract Corundum (Ruby-sapphire) is known to have formed in situ within Archean metamorphic rocks at several localities in the North Atlantic Craton of Greenland. Here we present two case studies for such occurrences: (1) Maniitsoq region (Kangerdluarssuk), where kyanite paragneiss hosts Ruby corundum, and (2) Nuuk region (Storo), where sillimanite gneiss hosts Ruby corundum. At both occurrences, ultramafic rocks (amphibole-peridotite) are in direct contact with the Ruby-bearing zones, which have been transformed to mica schist by metasomatic reactions. The bulk-rock geochemistry of the Ruby-bearing rocks is consistent with significant depletion of SiO 2 in combination with addition of Al 2 O 3 , MgO, K 2 O, Th and Sr relative to an assumed aluminous precursor metapelite. Phase equilibria modelling supports Ruby genesis from the breakdown of sillimanite and kyanite at elevated temperatures due to the removal of SiO 2 . The juxtaposition of relatively silica- and aluminum-rich metasedimentary rocks with low silica ultramafic rocks established a chemical potential gradient that leached/mobilized SiO 2 allowing corundum to stabilize in the former rocks. Furthermore, addition of Al 2 O 3 via a metasomatic reaction is required, because Al/Ti is fractionated between the aluminous precursor metapelites and the resulting corundum-bearing mica schist. We propose that Al was mobilized either by complexation with hydroxide at alkaline conditions, or that Al was transported as K-Al-Si-O polymers at deep crustal levels. The three main exploration vectors for corundum within Archean greenstone belts are: (1) amphibolite- to granulite-facies metamorphic conditions, (2) the juxtaposition of ultramafic rocks and aluminous metapelite, and (3) mica-rich reactions zones at their interface.
Inja Bogdan Allemann - One of the best experts on this subject based on the ideXlab platform.
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laser treatment of solar lentigines on dorsum of hands qs Ruby laser versus ablative co2 fractional laser a randomized controlled trial
European Journal of Dermatology, 2015Co-Authors: Nicola L Schoenewolf, Jurg Hafner, Reinhard Dummer, Inja Bogdan AllemannAbstract:Background Lentigines solares (LS) on the dorsum of hands are often esthetically disturbing. Q-switched Ruby laser treatment is highly effective in the treatment of these lesions. Ablative fractional photothermolysis may be a suitable alternative.We compared the Q-switched Ruby laser with ablative CO2 fractional photothermolysis for the treatment of solar lentigines.
Chris Yakymchuk - One of the best experts on this subject based on the ideXlab platform.
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Corundum formation by metasomatic reactions in Archean metapelite, SW Greenland: Exploration vectors for Ruby deposits within high-grade greenstone belts
Elsevier, 2018Co-Authors: Chris Yakymchuk, Kristoffer SzilasAbstract:Corundum (Ruby-sapphire) is known to have formed in situ within Archean metamorphic rocks at several localities in the North Atlantic Craton of Greenland. Here we present two case studies for such occurrences: (1) Maniitsoq region (Kangerdluarssuk), where kyanite paragneiss hosts Ruby corundum, and (2) Nuuk region (Storø), where sillimanite gneiss hosts Ruby corundum. At both occurrences, ultramafic rocks (amphibole-peridotite) are in direct contact with the Ruby-bearing zones, which have been transformed to mica schist by metasomatic reactions. The bulk-rock geochemistry of the Ruby-bearing rocks is consistent with significant depletion of SiO2 in combination with addition of Al2O3, MgO, K2O, Th and Sr relative to an assumed aluminous precursor metapelite. Phase equilibria modelling supports Ruby genesis from the breakdown of sillimanite and kyanite at elevated temperatures due to the removal of SiO2. The juxtaposition of relatively silica- and aluminum-rich metasedimentary rocks with low silica ultramafic rocks established a chemical potential gradient that leached/mobilized SiO2 allowing corundum to stabilize in the former rocks. Furthermore, addition of Al2O3 via a metasomatic reaction is required, because Al/Ti is fractionated between the aluminous precursor metapelites and the resulting corundum-bearing mica schist. We propose that Al was mobilized either by complexation with hydroxide at alkaline conditions, or that Al was transported as K-Al-Si-O polymers at deep crustal levels. The three main exploration vectors for corundum within Archean greenstone belts are: (1) amphibolite- to granulite-facies metamorphic conditions, (2) the juxtaposition of ultramafic rocks and aluminous metapelite, and (3) mica-rich reactions zones at their interface. Keywords: Ultramafic rocks, Kyanite, Sillimanite, Metasomatism, Pseudosection, Desilicificatio
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corundum formation by metasomatic reactions in archean metapelite sw greenland exploration vectors for Ruby deposits within high grade greenstone belts
Geoscience frontiers, 2017Co-Authors: Chris Yakymchuk, Kristoffer SzilasAbstract:Abstract Corundum (Ruby-sapphire) is known to have formed in situ within Archean metamorphic rocks at several localities in the North Atlantic Craton of Greenland. Here we present two case studies for such occurrences: (1) Maniitsoq region (Kangerdluarssuk), where kyanite paragneiss hosts Ruby corundum, and (2) Nuuk region (Storo), where sillimanite gneiss hosts Ruby corundum. At both occurrences, ultramafic rocks (amphibole-peridotite) are in direct contact with the Ruby-bearing zones, which have been transformed to mica schist by metasomatic reactions. The bulk-rock geochemistry of the Ruby-bearing rocks is consistent with significant depletion of SiO 2 in combination with addition of Al 2 O 3 , MgO, K 2 O, Th and Sr relative to an assumed aluminous precursor metapelite. Phase equilibria modelling supports Ruby genesis from the breakdown of sillimanite and kyanite at elevated temperatures due to the removal of SiO 2 . The juxtaposition of relatively silica- and aluminum-rich metasedimentary rocks with low silica ultramafic rocks established a chemical potential gradient that leached/mobilized SiO 2 allowing corundum to stabilize in the former rocks. Furthermore, addition of Al 2 O 3 via a metasomatic reaction is required, because Al/Ti is fractionated between the aluminous precursor metapelites and the resulting corundum-bearing mica schist. We propose that Al was mobilized either by complexation with hydroxide at alkaline conditions, or that Al was transported as K-Al-Si-O polymers at deep crustal levels. The three main exploration vectors for corundum within Archean greenstone belts are: (1) amphibolite- to granulite-facies metamorphic conditions, (2) the juxtaposition of ultramafic rocks and aluminous metapelite, and (3) mica-rich reactions zones at their interface.
Nicola L Schoenewolf - One of the best experts on this subject based on the ideXlab platform.
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laser treatment of solar lentigines on dorsum of hands qs Ruby laser versus ablative co2 fractional laser a randomized controlled trial
European Journal of Dermatology, 2015Co-Authors: Nicola L Schoenewolf, Jurg Hafner, Reinhard Dummer, Inja Bogdan AllemannAbstract:Background Lentigines solares (LS) on the dorsum of hands are often esthetically disturbing. Q-switched Ruby laser treatment is highly effective in the treatment of these lesions. Ablative fractional photothermolysis may be a suitable alternative.We compared the Q-switched Ruby laser with ablative CO2 fractional photothermolysis for the treatment of solar lentigines.
Yoshinori Mikashima - One of the best experts on this subject based on the ideXlab platform.
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a retrospective study looking at the long term complications of q switched Ruby laser in the treatment of nevus of ota
Lasers in Surgery and Medicine, 2001Co-Authors: Taro Kono, Motohiro Nozaki, Henry H Chan, Yoshinori MikashimaAbstract:Background and Objective: Despite the extensive use of QS Ruby, there is no report looking at its long-term complication in the treatment of nevus of Ota. To look at the long-term complications of nevus of Ota patients treated with QS Ruby laser. Study Design/Materials and Methods: A teaching hospital in Japan where over 400 patients with nevus of Ota had been treated since 1984. Hundred and one nevus of Ota patients that had been treated with QS Ruby laser, but had not received treatment for 12 months prior to the study, were called back for further assessment. Patients were called back to the hospital where they were interviewed and examined by two independent clinicians. Results: Hypopigmentation was the most common complication, affecting 16.8% of the patients and 5.9% had hyperpigmentation. One patient that had complete clearance post-laser surgery developed recurrence. Conclusion: QS Ruby laser is effective in the treatment of nevus of Ota. Recurrence is rare, but hypopigmentation is common and can be permanent. Further prospective study comparing its use with other Q-switched lasers is necessary. Lasers Surg. Med. 29:156–159, 2001. © 2001 Wiley-Liss, Inc.
