Seismic stratigraphic analysis of the Cenozoic sediments in the NW Faroe Shetland Basin – Implications for inherited structural control of sediment distribution

doi:10.1016/j.marpetgeo.2013.05.012

Marine and Petroleum Geology

Volume 46, September 2013, Pages 19-35

https://doi.org/10.1016/j.marpetgeo.2013.05.012 Get rights and content

Highlights

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Subsidence, pre-existing structure and influx controlled dispersal of sediments.
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Eocene subsidence rates exceed those expected from post-rift cooling of the basin.
•
The Heri, East Faroe and Trondur trends are important throughout Eocene-Recent times.
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Mid-Miocene inversion is followed by increased sediment input from the Faroe Islands.

Abstract

The post-basalt strata in the Faroese area have been investigated based on interpretation of 2D and 3D reflection seismic data. The post-basalt package is divided into 5 units which have led to the constructions of 6 structural maps and 5 thickness maps. Within the 5 units 12 prograding sediment bodies have been identified. Based on the interpretation it is possible to obtain an overview during time of the location of depocentres and direction of prograding units. Within Eocene time the depocentre was placed in the central part of the basin and the sediment influx was mostly from south and southwest. During Oligocene–Pliocene time the sediment influx was from north and northwest and the depocentre had moved in a westward direction closer to the Faroe Platform area.

Emplacement of the Cenozoic sediments in the Faroese sector of the Faroe-Shetland Basin is controlled by thermal subsidence of the basin, and local uplift of sediment source areas. Reactivation of older, Paleozoic and Mesozoic, structural elements seem to control the sediment path way and restrict the depositional areas. Various structural elements being re-activated at different times caused considerable structural complexity. Understanding the older, structural elements and their control on sedimentation is a potential tool for understanding deviations from “normal” thermal subsidence and for predicting the prospectivity in the post-basalt succession in the Faroe-Shetland Basin.

Introduction

Hydrocarbon exploration of Faroe Islands continental shelf started around 1994. Since then dense 2D and 3D seismic grids have been acquired covering the Faroese part of the Faroe-Shetland Basin and most of the Faroe Platform. In some areas the 2D seismic grid is dense, and the southernmost part of the Faroe-Shetland Basin is covered by 3D seismic data sets. 8 exploration wells have been drilled in the Faroe-Shetland Basin all located close to the UK border (Fig. 1).

Most of the previous studies regarding the post-basalt section in the Faroe-Shetland Basin are focussed on the south-eastern part of the basin. This article is concerned with the development of the Faroese part of the Faroe-Shetland Basin area through Cenozoic time with focus on the location of depocentres and sediment influx direction as the results of interplay between uplift, subsidence, inversion and reactivation of older structures by compression. Results from seismic interpretation of Early Eocene-Recent succession in Faroese sector of the Faroe-Shetland Basin are presented. Five seismic units of regional stratigraphic importance are identified within the study area and tied where possible to stratigraphic information from boreholes. For all five units the seismic character is described and structure and isopach maps are presented. The distribution of the individual Cenozoic units is compared with the location of Palaeozoic and Mesozoic structural elements (as outlined by Ritchie et al., 2011). From this comparison it appears that the location and outline of Cenozoic depocentres is guided by the pre-existing, Palaeozoic and Mesozoic structural elements.

Section snippets

Regional geological setting

The Faroe-Shetland Basin is a NE–SW trending basin located between the Shetland Islands and Faroe Islands. It developed as the result of several rift phases in Late Palaeozoic and Mesozoic times with the dominant basin forming faults being of NE–SW to N–S orientation (Doré et al., 1999; Roberts et al., 1999). This resulted in thinning of the crust to about 15 km along the axis of the Faroe-Shetland Basin (Bott, 1984; Hughes et al., 1998) and it has been suggested that the crust below the

Data

This study is based on interpretation of 2D (∼25,000 line km) and 3D (∼8000 km²) reflection seismic surveys acquired since 1994 in the Faroese part of the Faroe-Shetland Basin (Fig. 2). The dominant frequency and corresponding vertical resolution in the seismic data of the investigated post-basalt deposition is ranging from c. 47–86 Hz and 6.5–12 m (quarter-wavelength), respectively. The seismic data have been interpreted using the principles of seismic sequence stratigraphic analysis. Although

Sequence stratigraphy of the Eocene-recent succession of Faroe-Shetland Basin

The Eocene-Recent, post-basalt strata covers the Faroese part of the Faroe-Shetland Basin but thin out towards Munkagrunnur Ridge to the SW, Faroe Platform to the NW and Fugloy Ridge to the N (Figs. 1 and 4). Figure 3 summarize the stratigraphy of the Faroe-Shetland Basin, and illustrates correlation of stratigraphic units and surfaces used in this paper (Fig. 3, Column 4) with those used in previous studies (Andersen et al., 2000, 2002; Davies and Cartwright, 2002; Sørensen, 2003; Stoker

Discussion

The main sediment input directions into the Faroese part of the Faroe-Shetland Basin has shifted significantly through time, with Eocene being dominated by south to south-westerly sourced input while Oligocene to Recent mainly has a north to westerly source input (Figure 3, Figure 14, Figure 15, Figure 16). The various source input directions through Cenozoic time governed the locations of the depocentres (Fig. 16) from being in the centre of the basin in Eocene time to move farther towards the

Conclusion

During Cenozoic time a shift in sediment influx directions and location of depocentre take place in the Faroese part of Faroe-Shetland Basin which elucidate the tectonic development of the area.

Acknowledgements

The authors want to acknowledge Faroese Earth and Energy Directorate (Jarðfeingi), the Faroese Research Council, Statoil and ENI for funding this work which is a part of a PhD project. We also want to thank Martyn Stoker for pointing out that horizon T2d, which in the literature is believed to have a mid Mid Eocene age instead has an early Mid Eocene age and two anonymous referees for constructive review of the paper.

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Seismic stratigraphic analysis of the Cenozoic sediments in the NW Faroe Shetland Basin – Implications for inherited structural control of sediment distribution

Highlights

Abstract

Introduction

Section snippets

Regional geological setting

Data

Sequence stratigraphy of the Eocene-recent succession of Faroe-Shetland Basin

Discussion

Conclusion

Acknowledgements

Global and Planetary Change

Journal of Structural Geology

Marine and Petroleum Geology

Marin and Petroleum Geology

Marin and Petroleum Geology

Marin and Petroleum Geology

Marine Geology

Late Cretaceous and Early Tertiary extension and volcanism around the Faeroe Islands

Cenozoic evolution of the Faroe Platform: comparing denudation and deposition

The relationship between the distribution of the Tertiary sediments, tectonic processes and deep-water circulation around the Faeroe Islands

Late Paleocene–Miocene compression in the Faeroe-Rockall area

Tertiary development of the Faeroe-Rockall Plateau based on reflection seismic data

Bulletin of the Geological Society of Denmark

Tertiary compressional structures on the Faroe-Rockall Plateau in relation to northeast Atlantic ridge-push and Alpine foreland stresses

Tectonophysics

Deep structure and origin of the Faeroe-Shetland Channel

Tectonic evolution

Three-dimensional seismic imaging of Paleogene dike-fed submarine volcanoes from the northeast Atlantic margin

Geology

A fossilized Opal A to Opal C/T transformation on the northeast Atlantic margin: support for a significantly elevated Palaeogeothermal gradient during the Neogene?

Basin Research

Rifting and the development of the Faroe-Shetland Basin

Principal tectonic events in the evolution of the northwest European Atlantic margin

The stratigraphy, environment of eruption and age of the Faroes Lava Group, NE Atlantic Ocean

Onset of North Atlantic Deep Water production coincident with inception of the Cenozoic global cooling trend

Geology

Exploration in the Shetland-Faeroe Basin using densely spaced arrays of ocean-bottom seismometers

Geophysics

Aspects of the Cenozoic deformational history of the northeast Faroe-Shetland basin, Wyville-Thomson ridge and Hatton bank areas