Origin of seaward-dipping reflectors in oceanic crust off the Norwegian margin by “subaerial sea-floor spreading”

Mutter, John C.; Talwani, Manik; Stoffa, Paul L.

doi:10.1130/0091-7613(1982)10<353:oosrio>2.0.co;2

Cited by 327 publications

(232 citation statements)

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“…7 and 10). The Quaternary geology of the Danakil region is similar to that which is often inferred for the COT at magmatic rifted margins on the basis of seismic data: highly reflective sequences, usually termed sea-ward dipping reflectors (SDRs) reflect a large proportion of the controlled source seismic energy used to image them back to the surface (Maresh and White, 2005;Mutter, 1985;Mutter et al, 1982;White et al, 2008). The along-rift variation in rifting processes in the subaerial Red Sea rift in Afar suggests that an abrupt phase of plate stretching just prior to the onset of seafloor spreading can induce dramatic subsidence of a magmatic rift below sea-level .…”

Section: Implications For Magma Generation and The Formation Of Seawamentioning

confidence: 62%

“…However, it is difficult to interpret the geological record unambiguously because the tectonic activity that characterised breakup has long-since ceased and the continentocean transition (COT) is sometimes masked by up to several kilometres of late-to-syn rift interbedded basalt flows and sediments (often evaporites). These so-called seaward-dipping reflector sequences reflect back a large proportion of the seismic energy used to image beneath them in controlled-source experiments (Maresh and White, 2005;Mutter, 1985;Mutter et al, 1982;White et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

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The development of extension and magmatism in the Red Sea rift of Afar

et al. 2013

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Despite the importance of continental breakup in plate tectonics, precisely how extensional processes such as brittle faulting, ductile plate stretching, and magma intrusion evolve in space and time during the development of new ocean basins remains poorly understood. The rifting of Arabia from Africa in the Afar depression is an ideal natural laboratory to address this problem since the region exposes subaerially the tectonically active transition from continental rifting to incipient seafloor spreading. We review recent constraints on along-axis variations in rift morphology, crustal and mantle structure, the distribution and style of ongoing faulting, subsurface magmatism and surface volcanism in the Red Sea rift of Afar to understand processes ultimately responsible for the formation of magmatic rifted continental margins. Our synthesis shows that there is a fundamental change in rift morphology from central Afar northward into the Danakil depression, spatially coincident with marked thinning of the crust, an increase in the volume of young basalt flows, and subsidence of the land towards and below sea-level. The variations can be attributed to a northward increase in proportion of extension by ductile plate stretching at the expense of magma intrusion. This is likely in response to a longer history of localised heating and weakening in a narrower rift. Thus, although magma intrusion accommodates strain for a protracted period during rift development, the final stages of breakup are dominated by a phase of plate stretching with a shift from intrusive to extrusive magmatism. This late-stage pulse of decompression melting due to plate thinning may be responsible for the formation of seaward dipping reflector sequences of basalts and sediments, which are ubiquitous at magmatic rifted margins worldwide.

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Section: Implications For Magma Generation and The Formation Of Seawamentioning

confidence: 62%

Section: Introductionmentioning

confidence: 99%

The development of extension and magmatism in the Red Sea rift of Afar

et al. 2013

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“…8; Zhang et al, 2015). If lavas emanated from the center and were preferentially deposited there, the center should have subsided owing to isostatic adjustment, causing reflectors to dip inward towards the center, similar to seaward dipping reflectors (Mutter et al, 1982;Mutter, 1985;Planke et al, 2000) -but this is not observed. This finding implies that the edifice was constructed in complete isostatic balance.…”

Section: Accepted M Manuscriptmentioning

confidence: 98%

“…Intrabasement reflectors have also been imaged by seismic profiles on volcanic rifted margins, especially on the Vøring and Greenland margins (Hinz, 1981;Mutter et al, 1982;Planke and Eldholm, 1994;Planke and Cambray, 1996;Planke et al, 2000). Here coring demonstrated that the shallower layers are lava flows and volcaniclastic layers (Planke et al, 2000).…”

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confidence: 95%

Formation and evolution of Shatsky Rise oceanic plateau: Insights from IODP Expedition 324 and recent geophysical cruises

Sager

Sano

Geldmacher

2016

Earth-Science Reviews

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“…Two more characteristic features of volcanic passive margins are Seaward Dipping Reflectors (SDRs; interpreted as the expression of basaltic extrusions (Hinz, 1981;Mutter et al, 1982;White et al, 1987;White and McKenzie, 1989)), and usually more than 10 km thick syn-and post-rift sediments (White and McKenzie, 1989;Franke, 2013). It evolved in response to the North Atlantic breakup, presumably, initiated by the abnormally hot mantle of the Iceland plume (White, 1989;Skogseid et al, 1992;Ren et al, 1998;Tsikalas et al, 2002;Blystad et al, 1995;Gernigon et al, 2004Gernigon et al, , 2006.…”

Section: Geological Backgroundmentioning

confidence: 99%

Variability of geothermal gradient across two differently aged continental volcanic passive margins: The Southwest African and the Norwegian margins

Gholamrezaie

Scheck‐Wenderoth

Sippel

et al. 2017

Preprint

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Abstract. The aim of this study is to investigate the shallow thermal field differences for two differently aged passive continental margins by analyzing regional variations in geothermal gradient and exploring the controlling factors for these variations.Hence, we analyzed two previously published 3D conductive and lithospheric-scale thermal models of the Southwest African and the Norwegian passive margins. These 3D models differentiate various sedimentary, crustal and mantle units and integrate different geophysical data such as seismic observations and the gravity field. We extracted the temperature-depth distributions 5 in 1 km intervals down to 6 km below the upper thermal boundary condition. The geothermal gradient was then calculated for these intervals between the upper thermal boundary condition and the respective depth levels (1, 2, 3, 4, 5, and 6 km below the upper thermal boundary condition). According to our results, the geothermal gradient decreases with increasing depth and shows varying lateral trends and values for these two different margins. We compare the 3D geological structural models and the geothermal gradient variations for both thermal models and show how radiogenic heat production, sediment insulating 10 effect, and thermal LAB depth influence the shallow thermal field pattern. The results indicate an ongoing process of oceanic mantle cooling at the young Norwegian margin compared with the old SW African passive margin that seems to be thermally equilibrated at the present-day.

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Origin of seaward-dipping reflectors in oceanic crust off the Norwegian margin by “subaerial sea-floor spreading”

Cited by 327 publications

References 0 publications

The development of extension and magmatism in the Red Sea rift of Afar

The development of extension and magmatism in the Red Sea rift of Afar

Formation and evolution of Shatsky Rise oceanic plateau: Insights from IODP Expedition 324 and recent geophysical cruises

Variability of geothermal gradient across two differently aged continental volcanic passive margins: The Southwest African and the Norwegian margins

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