ORCID Profile
0000-0003-1891-3396
Current Organisation
Uppsala Universitet
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Publisher: Springer Science and Business Media LLC
Date: 29-06-2022
DOI: 10.1038/S41467-022-31348-7
Abstract: The basalts of the 2021 Fagradalsfjall eruption were the first erupted on the Reykjanes Peninsula in 781 years and offer a unique opportunity to determine the composition of the mantle underlying Iceland, in particular its oxygen isotope composition (δ 18 O values). The basalts show compositional variations in Zr/Y, Nb/Zr and Nb/Y values that span roughly half of the previously described range for Icelandic basaltic magmas and signal involvement of Icelandic plume (OIB) and Enriched Mid-Ocean Ridge Basalt (EMORB) in magma genesis. Here we show that Fagradalsfjall δ 18 O values are invariable (mean δ 18 O = 5.4 ± 0.3‰ 2 SD, N = 47) and indistinguishable from “normal” upper mantle, in contrast to significantly lower δ 18 O values reported for erupted materials elsewhere in Iceland (e.g., the 2014–2015 eruption at Holuhraun, Central Iceland). Thus, despite differing trace element characteristics, the melts that supplied the Fagradalsfjall eruption show no evidence for 18 O-depleted mantle or interaction with low-δ 18 O crust and may therefore represent a useful mantle reference value in this part of the Icelandic plume system.
Publisher: Oxford University Press (OUP)
Date: 03-08-2007
Publisher: Springer Science and Business Media LLC
Date: 26-09-2012
Publisher: Springer Science and Business Media LLC
Date: 29-08-2022
DOI: 10.1038/S43247-022-00518-2
Abstract: Sub-seafloor hydrothermal processes along volcanically active plate boundaries are integral to the formation of seafloor massive sulfide deposits and to oceanic iron cycling, yet the nature of their relationship is poorly understood. Here we apply iron isotope analysis to sulfide minerals from the Trans-Atlantic Geotraverse (TAG) mound and underlying stockwork, 26°N Mid-Atlantic Ridge, to trace hydrothermal processes inside an actively-forming sulfide deposit in a sediment-free mid-ocean ridge setting. We show that data for recently formed chalcopyrite imply hydrothermal fluid–mound interactions cause small negative shifts ( −0.1‰) to the δ 56 Fe signature of dissolved iron released from TAG into the North Atlantic Ocean. Texturally distinct types of pyrite, in turn, preserve a δ 56 Fe range from −1.27 to +0.56‰ that reflects contrasting precipitation mechanisms (hydrothermal fluid–seawater mixing vs. conductive cooling) and variable degrees of progressive hydrothermal maturation during the kyr evolution of the TAG complex. The identified processes may explain iron isotope variations found in fossil onshore sulfide deposits.
Publisher: Elsevier BV
Date: 07-2017
Publisher: Research Square Platform LLC
Date: 25-02-2022
DOI: 10.21203/RS.3.RS-1338313/V1
Abstract: Sub-seafloor hydrothermal processes along volcanically active plate boundaries are integral to the formation of seafloor massive sulfide (SMS) deposits and to oceanic Fe cycling, yet their nature is poorly understood. Here we apply Fe isotope analysis to sulfides from the TAG mound and underlying stockwork, 26°N Mid-Atlantic Ridge, to trace hydrothermal processes inside an actively-forming SMS deposit in a sediment-free mid-ocean ridge setting. We show that data for recently formed chalcopyrite imply fluid–mound interactions cause small negative shifts ( -0.1‰) to the δ 56 Fe signature of dissolved Fe released from TAG into the North Atlantic Ocean. Texturally resolved pyrite, in turn, preserves a δ 56 Fe range from − 1.27 to + 0.56‰ that reflects contrasting modes of formation (fluid–seawater mixing vs. fluid conductive cooling) and variable degrees of progressive hydrothermal maturation during the 20 kyr evolution of the TAG complex. The identified processes may explain Fe isotope variations found in fossil onshore sulfide deposits.
No related grants have been discovered for Valentin Troll.