Hydrothermal quartz and silica polymorphs display a larger range of δ 18O (-9.3 to +30.1 ‰) and δ 30Si (-4.6 to +0.7 ‰) values. Magmatic quartz reveals δ 18O (-5.6 to +6.6 ‰) and δ 30Si (-0.4 ± 0.2 ‰) values representative of mantle- and crustally-derived melts in Iceland. Quartz formation processes in the Icelandic crust were assessed using coupled δ 18O and δ 30Si systematics of silica deposits formed over a wide temperature range (550 ☌). NordVULK (Nordic Vulcanological Center), Landsvirkjun (2018) Silicon and oxygen isotopes unravel quartz formation processes in the Icelandic crust. ![]() Kleine, B.I., Stefánsson, A., Halldórsson, S.A., Whitehouse, M.J., Jónasson, K. While equilibrium isotope fractionation between fluids and quartz seems to prevail at high temperatures, kinetic fractionation likely influences isotope systematics at low temperatures.ġNordic Volcanological Center, Institute of Earth Sciences, University of Iceland, Reykjavik, IcelandĢInstitute of Earth Sciences, University of Iceland, Reykjavik, IcelandģSwedish Museum of Natural History, Stockholm, SwedenĤIcelandic Institute of Natural History, Garðabær, IcelandĪffiliations | Corresponding Author | Cite as | Funding informationĮmail: Volcanological Center, Institute of Earth Sciences, University of Iceland, Reykjavik, Iceland In context of published δ18O and δ30Si data on hydrothermal silica deposits, we demonstrate that large ranges in δ30Si values coupled to insignificant δ18O variations may result from silica precipitation in a hydrothermal fluid conduit associated with near-surface cooling. Isotope modelling reveals that such large variations are consistent with variable water sources and equilibrium isotope fractionation between fluids and quartz associated with secondary processes occurring in the crust, including fluid-rock interaction, boiling and cooling. Hydrothermal quartz and silica polymorphs display a larger range of δ18O (-9.3 to +30.1 ‰) and δ30Si (-4.6 to +0.7 ‰) values. ![]() Magmatic quartz reveals δ18O (-5.6 to +6.6 ‰) and δ30Si (-0.4 ± 0.2 ‰) values representative of mantle- and crustally-derived melts in Iceland. JónassonDO - ĪB - Quartz formation processes in the Icelandic crust were assessed using coupled δ18O and δ30Si systematics of silica deposits formed over a wide temperature range (550 ☌). T1 - Silicon and oxygen isotopes unravel quartz formation processes in the Icelandic crustĪU - B.I.
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