Mapping Sedimentary and Crustal Thicknesses in the Northern Atlantic Ocean from Public Domain Geophysical Data

Hermione Lofton, University of Nebraska-Lincoln

Document Type Thesis

Copyright 2025, Hermione Lofton. Used by permission

Abstract

The Northern Atlantic Ocean is a complex region that contains many inactive and active tectonic features. These features include the Jan Mayen Microcontinent, Jan Mayen Fracture Zone, Aegir Ridge, Kolbeinsey Ridge, the Greenland-Iceland-Faroe Ridge, the Voring Plateau, the Voring Spur, and the Iceland Hotspot. This project is motivated by the region’s complex geology and its highly debated tectonic history and disputed crustal affinity. This study aims to evaluate tectonic elements of the Northern Atlantic Ocean with three major objectives. The first objective is to develop a map of crustal thickness from publicly available seismic refraction data. For the second objective, publicly available seismic reflection data were used to develop a map of sedimentary thickness for the region. The third objective is to evaluate the boundaries of tectonic features in the study area from the developed crustal and sedimentary thickness maps.

The composed crustal thickness map showed the crust as thick as 42 km over the Greenland-Iceland-Faroe Ridge and as thin as ~2 km over the active Kolbeinsey Ridge. The sedimentary thickness map revealed that sediments varied greatly in the study area. The thickest sediments were mapped over the Voring Plateau, although our data does not allow us to uniquely map the basement, leaving room for some uncertainty. The thinnest sediments are located over the actively spreading centers, Kolbeinsey and Mohns Ridges. The results of this study show how crust and sediments differ throughout the region and how these variations are associated with tectonic features. The boundaries of tectonic features were interpreted from the developed maps. Comparisons with published crustal and sedimentary thickness datasets outlined several regions of discrepancies. Seismic data in those regions were carefully analyzed, revealing that these discrepancies relate to differences in interpretations of the basement. The thickness maps composed in this study are considered to be the most plausible.

Faculty mentor: Irina Filina