The Western Rockall Plateau: Stratigraphy and Structural Evolution

Roberts, D.G.; Montadert, L.; Searle, R. C.

doi:10.2973/dsdp.proc.48.155.1979

Cited by 32 publications

(54 citation statements)

References 26 publications

(52 reference statements)

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“…The geometry of the NAIP (Figs 2, 3) and the longevity of the igneous activity, together with the involvement of the Rockall-Faroe Islands microcontinent (Roberts & Searle, 1979;Edwards, 2002) and the Jan Mayen microcontinent (Kodaira et al 1998;Mjelde et al 2008) in the rift processes, suggest a complex and discontinuous break-up history. A comparable complex rifting evolution has been reported for the Afar Volcanic Province with migrating triple junctions and magmatism (Tesfaye, Harding & Kusky, 2003;Wolfenden et al 2004) and where microcontinents (Danakil and Aisha) were involved in the rifting/igneous processes and commonly defined their own secondary triple junctions and associated magmatism (Garfunkel & Beyth, 2006).…”

Section: C the Naip In The Context Of Rift Geometry And Triple Junmentioning

confidence: 99%

The onset of the North Atlantic Igneous Province in a rifting perspective

et al. 2009

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Abstract -The processes that led to the onset and evolution of the North Atlantic Igneous Province (NAIP) have been a theme of debate in the past decades. A popular theory has been that the impingement on the lower lithosphere of a hot mantle plume (the 'Ancestral Iceland' plume) initiated the first voluminous outbursts of lava and initiated rifting in the North Atlantic area in Early Palaeogene times. Here we review previous studies in order to set the NAIP magmatism in a time-space context. We suggest that global plate reorganizations and lithospheric extension across old orogenic fronts and/or suture zones, aided by other processes in the mantle (e.g. local or regional scale upwellings prior to and during the final Early Eocene rifting), played a role in the generation of the igneous products recorded in the NAIP for this period. These events gave rise to the extensive Paleocene and Eocene igneous rocks in W Greenland, NW Britain and at the conjugate E Greenland-NW European margins. Many of the relatively large magmatic centres of the NAIP were associated with transient and geographically confined doming in Early Paleocene times prior to the final break-up of the North Atlantic area.

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Section: C the Naip In The Context Of Rift Geometry And Triple Junmentioning

confidence: 99%

The onset of the North Atlantic Igneous Province in a rifting perspective

et al. 2009

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“…Margin led Roberts et al (1979) to suggest progradation of shallow-water and deltaic sediments interbedded with extrusives during the rifting stage. This hypothesis was modified after DSDP Leg 81 to an extrusive dipping sequence originating from dike intrusions throughout the region of stretching prior to spreading (Roberts et al, 1984b).…”

Section: V0ring Plateau Marginal Highmentioning

confidence: 99%

Evolution of the Vøring Volcanic Margin

Eldholm¹,

Thiede²,

Taylor³

1989

Proceedings of the Ocean Drilling Program

136

107

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ODP Sites 642 and 643 recovered a succession of rocks which have greatly improved the understanding of how the Cenozoic volcanic Wring Margin evolved, particularly by providing important constraints on the series of events that occurred during the initial opening of the Norwegian-Greenland Sea. The more than 900 m of igneous rocks and interbedded sediments drilled at Site 642 constitute two distinct, strikingly different volcanic series. The upper series, composed of transitional mid-oceanic tholeiitic lava flows and thin interbedded volcaniclastic sediments confirmed the seaward-dipping reflectors to be a terrestrially constructed extrusive complex. The lower series, probably extending for several hundred meters below the bottom of the hole, consists of another flow complex of dacitic composition, some dikes and thicker interbedded sediments, partially continentally derived. We suggest that the margin evolved by crustal extension in the Paleocene accompanied by uplift and a progressively more intense invasion of dikes and sills in the rift zone. Just prior to breakup, magma from shallow crustal melts produced the lower series. The upper series was constructed during an intense, rapidly waning, volcanic surge of subaerial accretion of oceanic magma following breakup in middle of Chron 24.2R. The surge is characterized by a much increased rate of magma production and high spreading rate. The upper series cover both newly formed oceanic crust and large areas of the adjacent thinned continental crust. The dipping wedge was formed by subsidence due to loading and thermal contraction, possibly amplified by a tectonic force. When the surge had abated, the injection center quickly subsided and normal oceanic crust was formed. Our interpretation is that the continent/ocean boundary occurs at the seaward termination of reflector K, which separates the two volcanic series. However, a region of strongly intruded transitional crust is inferred in 30-to 50-km wide zones on either side of the Vdring Plateau Escarpment.The Wring Margin experienced crustal uplift and extension prior to breakup, restricted to a Tertiary marginal basin west of the present shelf edge. The initial volcanic surge and shallow extrusion level are related to a higher than normal temperature at the base of the lithosphere, inducing partial melting combined with opening in previously thinned crust. The commonly described non-extensional nature of this margin is only an apparent phenomenon. Except for the outer basin, extension by dike injection coupled with high strength of the thin, pre-opening crust in the Vdring Basin precluded the formation of a faulted rift unconformity. We believe these observations have relevance for volcanic margins elsewhere, but infer that seaward-dipping reflectors can form in many environments.The Wring Plateau marginal high and other similar features in the North Atlantic are an integrated part of the North Atlantic Volcanic Province, which extends 2000 km longitudinally. Compared to the central, transverse, part of ...

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“…Type II is predominantly colorless, pale pink or pale green, and strongly resembles the variety diallage, as described by Kerr (1959, pp. 308-309 Roberts et al (1979), showing locations of the DSDP holes discussed in this chapter. …”

Section: Heavy Mineral Assemblagesmentioning

confidence: 99%

Heavy Minerals from Paleogene Sediments, Deep Sea Drilling Project Leg 81: Their Bearing on Stratigraphy, Sediment Provenance, and the Evolution of the North Atlantic

Morton¹

1984

Initial Reports of the Deep Sea Drilling Project

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Five heavy mineral associations occur in the Paleocene and Eocene sediments recovered during Leg 81 of the Deep Sea Drilling Project (DSDP) in the SW Rockall area. Association 1, consisting of augite, iddingsite, and olivine, was derived from the basaltic rocks of the northern part of the Rockall Plateau. Association 2 consists of epidote group minerals, including piedmontite, and amphiboles of actinolite, actinolitic hornblende, and magnesio-hornblende compositions, and was derived from the metamorphic basement of south Greenland. Association 3 comprises garnet, augite, apatite, and edenitic and pargasitic amphiboles and has a provenance in the southern Rockall Plateau. Associations 4 (garnet, apatite, edenitic/pargasitic amphiboles) and 5 (garnet, apatite) are intrastratal solution derivatives of Association 3, with successive removal of first pyroxene and then amphibole with increasing depth of burial.Throughout the SW Rockall Plateau area there is a significant change in the spectrum of the above assemblages in the lower part of the Eocene. This change has been noted at Sites 403, 404, 553, and 555 and is defined by the last appearance of Association 2. This level therefore marks the cessation of sediment supply from southern Greenland and is the result of the final separation of Rockall and Greenland immediately prior to magnetic Anomaly 24.

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The Western Rockall Plateau: Stratigraphy and Structural Evolution

Cited by 32 publications

References 26 publications

The onset of the North Atlantic Igneous Province in a rifting perspective

The onset of the North Atlantic Igneous Province in a rifting perspective

Evolution of the Vøring Volcanic Margin

Heavy Minerals from Paleogene Sediments, Deep Sea Drilling Project Leg 81: Their Bearing on Stratigraphy, Sediment Provenance, and the Evolution of the North Atlantic

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