Structure and evolution of the continental margin off Norway and the Barents Sea

Faleide, Jan Inge; Tsikalas, Filippos; Breivik, A. J.; Mjelde, Rolf; Ritzmann, O.; Engen, Øyvind; Wilson, J. Tuzo; Eldholm, Olav

doi:10.18814/epiiugs/2008/v31i1/012

Cited by 410 publications

(383 citation statements)

References 70 publications

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“…Because Scandinavia's offshore margin structure is well known from seismic-refraction and seismic-refl ection studies (Raum et al, 2002;Mjelde et al, 2003;Ebbing et al, 2006;Faleide et al, 2008;Ebbing and Olesen, 2010;Reynisson, 2010, and citations therein), our measurements can be made with confi dence. However, like several other passive margins, the Scandinavian margin is characterized by lower-crustal bodies (LCBs) exhibiting seismic velocities higher than expected for the lower crust and lower than expected for the mantle (see Eldholm and Mutter, 1986;Ebbing et al, 2006).…”

Section: Crustal Taper and Escarpment Elevations In Scandinaviamentioning

confidence: 99%

The long-term topographic response of a continent adjacent to a hyperextended margin: A case study from Scandinavia

Redfield

Osmundsen²

2012

Geological Society of America Bulletin

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We present data that link Scandinavia's passive-margin domains under a unifi ed system invoking isostatically driven, postextension phase vertical adjustments to severe crustal thinning. Topographic and geological data indicate that the relative location of the fi rst landward occurrence of total crustal embrittlement or deformation coupling-the Taper Break-controlled and continues to control Scandinavia's post-thinning geomorphic evolution. Formed during Late Jurassic or Early Cretaceous thinning, yet marked today by seismicity, the Taper Break closely approximates the boundary between (1) less-stretched lithosphere that increases in rigidity both toward land and through postrift time, and (2) the highly attenuated, pervasively faulted, permanently weakened lithosphere of the distal margin. Following the stretching, thinning, and exhumation phases proposed by other workers, an accommodation phase is warranted. Commencing during "sag" basin time and continuing today, it is probably driven by thermal cooling and mass transfer from the escarpment to the basins offshore. The accommodation phase does not entirely coincide with the traditional postrift phase as the former may contain the latter. During accommodation, the original synrift escarpments can be eroded to very low base levels. Sharply tapered margin segments can undergo subsequent rejuvenation by out-of-sequence normal faulting and footwall uplift, probably in response to tensile bending stresses engendered by lithosphericscale fl exure. Accommodation-phase uplift at passive margins is the inexorable and penultimate phase of hyperextension, and may perhaps be followed by the onset of subduction localized by the weakened lithosphere of the distal margin and the ocean-continent transition.

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Section: Crustal Taper and Escarpment Elevations In Scandinaviamentioning

confidence: 99%

The long-term topographic response of a continent adjacent to a hyperextended margin: A case study from Scandinavia

Redfield

Osmundsen²

2012

Geological Society of America Bulletin

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“…Low sea-level, aridity and rifting resulted in the widespread terrestrial clastic deposits with red beds and evaporites in Central and Western Europe during the Early Triassic (Ziegler 1982;Ronov et al 1989). Mixed coarse and fine-grained clastics prevailed on the Barents shelf (Rønnevik et al 1982;Johansen et al 1993;Bogatski et al 1996;O'Leary et al 2004;Faleide et al 2008;Riis et al 2008;Tugarova et al 2008). Marginal marine environment with clastic deposition existed in the seaway between Europe and Greenland (Stemmerik 2000).…”

Section: Upper Absaroka I: Ladinian (Induan-lower Carnian) 251-225 Mamentioning

confidence: 99%

“…Alaska, Sverdrup, and Barents Sea) contain black shales that have source rock potential (Leith et al 1993;Parrish et al 2001). In general, mixed coarse and fine-grained clastics were deposited on the Barents shelf (Rønnevik et al 1982;Johansen et al 1993;Bogatski et al 1996;O'Leary et al 2004;Faleide et al 2008;Riis et al 2008;Tugarova et al 2008). Terrestrial clastics were deposited on Siberia, while a marine environment prevailed in the Verkhoyansk area (Ronov et al 1989).…”

Section: Upper Absaroka Ii: Norian (Late Carnian -Middle Hettangian)mentioning

confidence: 99%

Chapter 6 Phanerozoic palaeoenvironment and palaeolithofacies maps of the Arctic region

Golonka

2011

Memoirs

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Sixty-three maps illustrate geodynamic evolution and development of palaeoenvironments and palaeolithofacies of the Circum-Arctic region during Phanerozoic times. After the break-up of Rodinia and Pannotia in the Early Palaeozoic, the major Arctic plates Baltica, Siberia and Laurentia drifted from their original position around the South Pole towards the Supercontinent Pangea, which existed in the equatorial position during Late Palaeozoic and Early Mesozoic times. During the Mesozoic and Cenozoic plates gathered around newly formed Arctic Ocean. Large continental masses were assembled from major plates and numerous small plates and terranes on the northern hemisphere and around the North Pole. All the continents were by now connected. Carbonates were abundant in Siberia and Laurentia during Palaeozoic times. Clastic sedimentation prevailed during Mesozoic and Cenozoic times. The distribution of lithofacies shows climatic change associated with continental assembly and disassembly as well as with the steady northward drift of the continents.

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“…The fact that Svalbard, displaying a transect of Caledonian structures (Harland, 1985), remained adjacent to NE Greenland until the NE Atlantic began to open means that the route of our supposedly Devonian separation traversed the Barents Sea shelf also. That would explain this gap in the Caledonian orogen, a gap traversed by several Late Paleozoic rift structures (Faleide et al, 2008). Reconstruction with this in mind suggests that Greenland's southwestward motion along the MTFZ may be marked on Greenland by the NE-trending line of Cretaceous basalts that passes through Wollaston Foreland, central East Greenland (Escher and Pulvertaft, 1995); this movement, perhaps limited to <100 km, was followed by a much bigger northward (present Scandinavian coordinates) one, which would provide the Svalbard-Tromsø(?)…”

Section: Western Gneiss Region (Wgr) Southwestern Norwaymentioning

confidence: 99%

Basal Subduction Tectonic Erosion (STE), Butter Mélanges, and the Construction and Exhumation of HP-UHP Belts: The Alps Example and Some Comparisons

Osmaston

2008

International Geology Review

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Studies of high-pressure-ultrahigh-pressure (HP-UHP) belts stand to benefit from having a better idea of how subduction constructs them. Their exhumation, too, merits a closer look at epeirogenic processes. Progress in both these matters now appears possible and their relevance tested, using the Alps, the world's most comprehensively studied such belt, as the prime example. Its comparative youth means that less of the potentially pertinent surface detail has been lost by erosion or burial.Much evidence suggests that subduction downbend is actually not a flexure but is a seismically evident, escalator-like, through-plate step-faulting process. Especially where the subducting plate is younger than about 90 Ma, this gives it the property (STE) of incorporating upper-plate material in the step-angles, thus moving forward the position of the downbend surface that it has carved in the upper plate rapidly, and at a shallow angle for hundreds of kilometers. This yields a nominally "flat" interface profile, above which, at the shallow end of the system, the upper-plate crust will have been chilled and perhaps had its lower part removed, thus providing an origin for basement thrust sheets and (as subducted imbricate slices) those seen in HP-UHP belts.Seismology shows that "flat" interface profiles often pass through an inflection nearer the trench. This means that STE is "taking a second cut" and then disgorges the step-angle material along the succeeding flat part of the interface. When a STE-thinned margin imbricates, this diagnostic material appears as a fluid-overpressured tectonic mélange "buttered" (no shearing at the contact) onto the underside of each. Included floaters (up to >5 km in size) exhibit many lithologies, even slickensided, in an ex-oceanic, usually pelitic matrix that protected them from deformation. This "butter" is a focus of attention in HP-UHP belts, especially for its mafic-ultramafic floaters, while the water in its matrix seems important for reaction kinetics, for eventual epeirogenic action, and even to flux partial melting.Subduction of imbricate slices, already cooled by STE beneath them, and their successive lodgement beneath the "roof" and angle of the distant downbend profile carved by STE into the hanging wall, builds a subcreted triangular section extending far down the back wall, much further than hitherto thought possible. So this part exhumes the most, breaking through the "roof" above as a fault-line prone to strike-slip (Insubric, Møre-Trøndelag, Median Tectonic Line).In the Alps, and following extensive STE from the north, successive imbrication marked by Cretaceous flysch sequences transposed the paleogeographic order, so the Piemont ophiolites were from an oceanic-crusted northern forearc, not a separate ocean. Such transpositions cannot happen during collision; they require too much transport. During Eocene collision, the old block-and-basin structure in the European autochthon was epeirogenically rejuvenated (external massifs, Tauern window) by deep-crust heating and petrologic...

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Structure and evolution of the continental margin off Norway and the Barents Sea

Cited by 410 publications

References 70 publications

The long-term topographic response of a continent adjacent to a hyperextended margin: A case study from Scandinavia

The long-term topographic response of a continent adjacent to a hyperextended margin: A case study from Scandinavia

Chapter 6 Phanerozoic palaeoenvironment and palaeolithofacies maps of the Arctic region

Basal Subduction Tectonic Erosion (STE), Butter Mélanges, and the Construction and Exhumation of HP-UHP Belts: The Alps Example and Some Comparisons

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