Fracture zones and rift systems of eastern Iceland: Tectonic and geodynamic links to extinct rifts on the Iceland-Faroe Ridge and Iceland Plateau.

Poster from EGU24:

Blischke, A., Brandsdóttir, B., Karson, J. A., and Erlendsson, Ö.: Fracture zones and rift systems of eastern Iceland: Tectonic and geodynamic links to extinct rifts on the Iceland-Faroe Ridge and Iceland Plateau, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12369, https://doi.org/10.5194/egusphere-egu24-12369, 2024. 

Abstract: 

In the wake of the North-Atlantic Geoscience Tectonostratigraphic Atlas (NAGTEC) project and the mapping of the Jan Mayen microcontinent and Iceland Plateau region a comprehensive study of re-processed and new geological and geophysical data is needed to establish a detailed kinematic model of the NE-Atlantic region, linking the tectonic evolution of Iceland to the offshore Iceland Plateau Rifts, the Iceland-Faroe Ridge, and the Iceland-Faroe Fracture Zone regions. Acquisition of new tectonic and structural data from extinct rift zones on land is required to further our understanding of offshore rift systems. Kinematic models indicate that Northeast Iceland and its insular shelf formed by asymmetric spreading similar to the Iceland Plateau Rift under the influence of the Iceland mantle plume. These processes created multiple volcanic rift zones, fracture zones, and strike-slip elements that accommodated the breakup and formation of crustal domains north of Iceland, such as the Iceland-Faroe Fracture Zone (IFFZ), and along the Iceland-Faroe Ridge. Recent structural mapping within the Tröllaskagi-Flateyjarskagi region and the Tjörnes Fracture Zone have revealed stress-field variations within an overall right-lateral obliquely opening rift zone that includes N-S to NNE-SSW striking left-lateral strike-slip fault systems that serve as an analogue case. This corresponds to changes and rotations in dyke strike directions adjacent to the Dalvík lineament of the Húsavík-Flatey Fault system since the Mid-Miocene. To map out structural evidence and geometries for old and abandoned propagating rift systems onshore NE Iceland, we conducted preliminary fieldwork in the Vopnafjörður region, which we aim to continue within the next three years. Our goal is to delineate abandoned rift segments within NE Iceland and model the evolution of individual rift systems with time, to determine if younger rifts cut through or have discordant trends in respect to older rift structures. We plan to assess, how onshore Miocene rift systems (~15-6 Ma) align to older Miocene systems offshore and whether the IFFZ is a pseudo-fault that developed gradually during rift propagation or a prominent feature along the NE insular margin of Iceland, within a segmented Tertiary transform zone system. Our multidisciplinary approach will thus further our understanding of the dynamics of rift zone development and transfer in proximity to the Iceland mantle plume.