Midway evaluation in Geology - Noemi Löw

Event on Teams

Title: Geochemical and petrological variability of the Fjallgarðar Volcanic Ridge

Doctoral candidate: Noemi Löw

Doctoral committee:
Sæmundur Ari Halldórsson, Research Scientist at the Institute of Earth Sciences
Enikö Bali, Associate Professor at the Faculty of Earth Sciences
Guðmundur Heiðar Guðfinnsson, Research Scholar at the Institute of Earth Sciences
Simon Matthews, Research Associate at Cambridge University
Christoph Beier, Professor at the University of Helsinki

Abstract
The Earth is constantly rebuilding its crust along mid-ocean ridges (MOR) where oceanic plates drift apart and rock from the underlying mantle melts to form new basaltic crust. Understanding how these plate boundaries evolve and how they interact with the presence of nearby mantle plumes requires direct access to the MOR, yet this is typically hindered by the lack of MOR segments above sea level. MOR’s undergo frequent, small-scale lateral shifts in position, a process that has been recognized on submarine MOR segments but also on the subaerial Icelandic Plateau.
The Fjallgarðar Volcanic Ridge (FVR), a subglacially erupted hyaloclastite ridge complex extending from Central-East Iceland to the Melrakkaslétta peninsula in the North of Iceland, may represent the first evidence for an eastward excursion of the currently active Northern Rift Zone (NRZ). The original model envisaged the emplacement of the FVR into an early-stage plate boundary, and that magmatism ultimately proceeded back to the NRZ.
This project compiles a comprehensive new dataset on the relatively unexplored FVR, including major and trace elements, radiogenic (Pb-Sr-Nd-Hf) and stable isotopes (oxygen), noble gas chemistry (He-Ne-Ar) on subglacially erupted glass, whole-rock powders, minerals and melt inclusions in minerals, along with Ar-Ar dates. Using this data, we aim to place new constraints on the mantle sources and crustal processes contributing to magmatic activity along the FVR. Ultimately, the FVR serves as a testbed to better understand the interaction and distribution of rift and mantle plume magmatism in a near-rift setting.