The Greenland–Iceland–Faroe Ridge Complex

Árni Hjartarson,Anett Blischke,Ögmundur Erlendsson

doi:10.1144/sp447.14

Árni Hjartarson, Anett Blischke + Show 1 more

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https://doi.org/10.1144/sp447.14

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Abstract

Abstract The Greenland–Iceland–Faroe Ridge Complex (GIFRC) has been forming since the opening of the NE Atlantic (<55 Ma), standing out as a prominent feature on all geoscientific datasets. Our interpretations have revealed several new potential abandoned rift centres, mapped as syncline and anticline structures. The synclines are suggested to be manifestations of former rift axes that were abandoned by rift jumps. These appear to be more common inside the GIFRC region than in the adjacent ocean basins, and can be confirmed by observations of cumulative crustal accretion data through time. A major post-40 Ma unconformity is proposed across the East Iceland Shelf, forming a distinct 16–20 myr-long hiatus that is covered by a thick, younger sedimentary section. Several seamounts were identified on multibeam datasets at around 1200 m water depth in the Vesturdjúp Basin, just south of the Greenland–Iceland Ridge. These seamounts appear to be younger in formation time than the surrounding ocean floor, possibly indicating a still active intraplate volcanic zone. Young tectonic features, such as faults, graben and transverse ridges, characterize the area and present a good example of the complexity of the GIFRC in comparison to the adjacent abyssal plain.

Highlights

The purpose of this study is to review the structural segmentation and links to chronostratigraphic processes affecting the areas of the Greenland– Iceland Ridge (GIR), the Iceland Plateau and the Iceland –Faroe Ridge (IFR) (Figs 1 & 2; Table 1)
This review addresses the initiation of the Greenland–Iceland–Faroe Ridge Complex (GIFRC), its extent, defines rift jump areas within the complex, and addresses the Iceland-type central volcanoes and seamounts in their offshore regions
Despite a small areal outline compromise between the different datasets, comprising bathymetry, gravity, magnetic and crustal thickness maps along with seismic profiles over the region, all show the area as an anomalous feature within the oceanic crustal fabric of the NE Atlantic

Summary

Introduction

The purpose of this study is to review the structural segmentation and links to chronostratigraphic processes affecting the areas of the Greenland– Iceland Ridge (GIR), the Iceland Plateau and the Iceland –Faroe Ridge (IFR) (Figs 1 & 2; Table 1). Abandoned rift systems have previously been mapped for the onshore region of Iceland for the last 16 myr (Hjartarson 2003; Johannesson & Sæmundsson 2009) (Table 3), and in offshore areas around Iceland by Vogt (1971), Talwani & Eldholm (1977), Harðarson et al (1997), Vogt & Jung (2009) and Erlendsson & Blischke (2013) These extinct rift systems show a distinct dip of subaerial lava-flow formation sequences from both sides towards the old rift centre THE GREENLAND–ICELAND– FAROE RIDGE COMPLEX poorly understood due to the lack of geological profiles, dated rock samples from the offshore areas, and difficulties in interpreting consistent magnetic chron data across the region (Gaina et al 2017) (Fig. 3a)

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