Modeling the Greenland-Iceland-Faroe Ridge Using Integrated Geophysical Analysis

Authors

Zachary Clowdus, University of Nebraska-LincolnFollow

First Advisor

Irina Filina

Committee Members

Lynne Elkins, Christian Hübscher

Date of this Version

12-2025

Document Type

Thesis

Citation

A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science

Major: Earth and Atmospheric Sciences

Under the supervision of Professor Irina Filina

Lincoln, Nebraska, December 2025

Comments

Copyright 2025, Zachary Clowdus. Used by permission

Abstract

The Greenland-Iceland-Faroe Ridge (GIFR) is an area of significant geologic interest with anomalously thick crust related to enhanced melt generation from the interaction between the Mid-Atlantic Ridge and the Iceland hotspot. To the northeast of Iceland lies the Jan Mayen Microcontinent (JMMC), which is a continental fragment separated from Greenland during the opening of the Northern Atlantic. The overall extent of the JMMC, especially its southern boundary, remains poorly constrained. The crust beneath the GIFR is believed to be primarily of oceanic affinity. However, a recent discovery of felsic lavas in Iceland led to an alternative hypothesis that implies the possibility of a continental affinity for the GIFR. The proposed “Icelandia” is a sunken continent, underlying the GIFR and JMMC, composed of 3-10 km of mafic magma flows and dykes underlain by up to 30 km of magma-inflated continental crust. Resolving the crustal nature of the GIFR would provide critical information on the development of volcanic rifted margins, divergent boundaries, and melt generation from hot spots. The first objective of this work is to assess the plausibility of the continental hypothesis for the GIFR by integrating multiple geophysical datasets. We utilize published velocity models, gravity and magnetic anomaly data, and other geological datasets to develop simplified models of the GIFR crust and test both continental and oceanic scenarios. The modeling revealed that a continental scenario is as likely as an oceanic one as both describe the potential fields data relatively well. For the oceanic scenario, we also evaluated the Continent-Ocean Boundary (COB) on both sides of GIFR. The COB on the Faroe side remains difficult to constrain. On the Greenland side, we support the interpretation by Yuan et al. (2020), which is further east than published by most tectonic models. The second objective of this study is to reassess the southern boundary of the JMMC. Our analysis suggests that the crust between JMMC and Iceland Plateau is of continental affinity as it has the same signatures as thinned and intruded continental crust on the Greenland margin of the GIFR. Our main conclusion is that we are unable to rule out the possibility of magma-inflated lower continental crust beneath the GIFR.

Advisor: Irina Filina