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ORIGINAL RESEARCH article

Front. Earth Sci.
Sec. Petrology
Volume 12 - 2024 | doi: 10.3389/feart.2024.1501694

Magmatic evolution and architecture of an oceanic intraplate volcano: Vesteris Seamount, Atlantic Ocean

Provisionally accepted
Lea Belosa Lea Belosa 1*David Murphy David Murphy 2Teresa Ubide Teresa Ubide 3Sara Callegaro Sara Callegaro 1Christine Meyzen Christine Meyzen 4Michael Bizimis Michael Bizimis 5Adriano Mazzini Adriano Mazzini 1
  • 1 University of Oslo, Oslo, Norway
  • 2 Queensland University of Technology, Brisbane, Queensland, Australia
  • 3 The University of Queensland, Brisbane, Queensland, Australia
  • 4 Department of Geosciences, School of Sciences, University of Padua, Padua, Veneto, Italy
  • 5 Earth Ocean and Environment, College of Arts and Sciences, SC, USA, Columbia, United States

The final, formatted version of the article will be published soon.

    Vesteris is a large (33 x 27 km) and young (summit age: 0.65 – 0.010 Ma) intraplate seamount located in the Greenland Sea. The volcano has an ocean island basalt (OIB) origin. It is composed of alkali basalt, basanite/tephrite, phonotephrite, mugearite, and benmoreite, with a phenocryst assemblage including clinopyroxene, plagioclase, olivine, amphibole, rare haüyne, and oxides (Ti–magnetite and Cr–spinel). The phenocrysts may host inclusions of apatite, sulfides (pyrrhotite), and melt. Here, we report micro–chemical analyses of phenocrysts, groundmass microcrysts, melt inclusions, and groundmass glass. We apply mineral–melt thermobarometry to unravel the pre– to syn–eruptive crystallization history and the architecture of the plumbing system. Thermobarometry on clinopyroxene–liquid pairs indicates the main storage of basanite liquids in the upper mantle (∼ 6.4 kbar; ∼ 22 km). Storage could be multi–level, with the deepest level (∼ 9 kbar, ∼ 30 km depth) producing low-Mg dark green clinopyroxene cores with bright BSE contrast. The abundance of low-Mg cores in erupted products suggests a relatively fast ascent from mantle depths to the surface. Textural and compositional zoning of phenocrysts, especially clinopyroxenes, indicate that mafic recharge was a key process in driving the remobilization of the evolved clinopyroxene mush through the Vesteris plumbing system. Mafic recharge magmas also carried early olivine crystals that became overgrown by high-Mg clinopyroxene upon mixing with more evolved melt. This study provides evidence for major crystal fractionation in the uppermost mantle beneath a large seamount, similar to low magma flux ocean island basalt volcanoes.

    Keywords: Intraplate volcanism, Clinopyroxene zonation, Thermobarometry, Vesteris Seamount, NE Atlantic, Clinopyroxene geochemistry, Plumbing system architecture

    Received: 25 Sep 2024; Accepted: 15 Nov 2024.

    Copyright: © 2024 Belosa, Murphy, Ubide, Callegaro, Meyzen, Bizimis and Mazzini. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Lea Belosa, University of Oslo, Oslo, Norway

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