Constraints on Rifting Processes from Refraction and Deep-Tow Magnetic Data: The Example of the Galicia Continental Margin (West Iberia)

Sibuet, Jean‐Claude; Louvel, V.; Whitmarsh, R. B.; White, R. S.; Horsefield, Susan J.; Sichler, B.; Léon, Pierre; Recq, Maurice

doi:10.1007/978-94-011-0043-4_11

Cited by 35 publications

(61 citation statements)

References 35 publications

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“…In contrast a serpentinized ridge corresponding to serpentinized peridotite was found in the west Iberia non-volcanic margin (e.g. Sibuet et al, 1995;Pinheiro et al, 1996). However, those characters are not identified in northern margin of the SCS.…”

Section: Characteristics Of the Continent-ocean Transitionmentioning

confidence: 91%

Crustal Thinning of the Northern Continental Margin of the South China Sea

et al. 2004

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Magnetic data suggest that the distribution of the oceanic crust in the northern South China Sea (SCS) may extend to about 21°N and 118.5°E. To examine the crustal features of the corresponding continent-ocean transition zone, we have studied the crustal structures of the northern continental margin of the SCS. We have also performed gravity modeling by using a simple four-layer crustal model to understand the geometry of the Moho surface and the crustal thicknesses beneath this transition zone. In general, we can distinguish the crustal structures of the study area into the continental crust, the thinned continental crust, and the oceanic crust. However, some volcanic intrusions or extrusions exist. Our results indicate the existence of oceanic crust in the northernmost SCS as observed by magnetic data. Accordingly, we have moved the continent-ocean boundary (COB) in the northeastern SCS from about 19°N and 119.5°E to 21°N and 118.5°E. Morphologically, the new COB is located along the base of the continental slope. The southeastward thinning of the continental crust in the study area is prominent. The average value of crustal thinning factor of the thinned continental crust zone is about 1.3-1.5. In the study region, the Moho depths generally vary from ca. 28 km to ca. 12 km and the crustal thicknesses vary from ca. 24 km to ca. 6 km; a regional maximum exists around the Dongsha Island. Our gravity modeling has shown that the oceanic crust in the northern SCS is slightly thicker than normal oceanic crust. This situation could be ascribed to the post-spreading volcanism or underplating in this region.

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Section: Characteristics Of the Continent-ocean Transitionmentioning

confidence: 91%

Crustal Thinning of the Northern Continental Margin of the South China Sea

et al. 2004

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“…The S reflector can be followed oceanward towards a ridge consisting of serpentinized peridotites, the so-called peridotite ridge (Boillot et al 1980). This ridge is supposed to separate "true" oceanic crust to the west from a "transitional" and thinned continental crust to the east (Sibuet et al 1995).…”

Section: The Distal Marginmentioning

confidence: 99%

New models for evolution of magma-poor rifted margins based on a review of data and concepts from West Iberia and the Alps

Manatschal

2004

Int J Earth Sci (Geol Rundsch)

422

333

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Direct observation and extensive sampling in ancient margins exposed in the Alps, combined with drillhole and geophysical data from the present-day Iberia margin, result in new concepts for the strain evolution and near-surface response to lithospheric rupturing at magmapoor rifted margins. This paper reviews data and tectonic concepts derived from these two margins and proposes that extension, leading to thinning and final rupturing of the continental lithosphere, is accommodated by three fault systems, each of them characterized by a specific temporal and spatial evolution during rifting of the margin, by its fault geometry, and its surface response. The data presented in this paper suggest that margin architecture and distribution of rift structures within the future margin are controlled first by inherited heterogeneities within the lithosphere leading to a contrasting behaviour of the future distal and proximal margins during an initial stage of rifting. The place of final break-up appears to be determined early in the evolution of the margin and occurs where the crust has been thinned during a first stage to less than 10 kilometres. During final break-up, the rheology of the extending lithosphere is controlled by the thermal structure related to the rise of the asthenosphere and by serpentinization and magmatic processes.

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“…The western Galicia continental margin has been defined as a sediment-starved, non-volcanic rifted margin (e.g., Montadert et al, 1974;Boillot et al, 1979;Groupe Galice, 1979;Sibuet and Ryan, 1979;Chenet et al, 1982;Boillot et al, 1987;Sibuet, 1992;Boillot et al, 1995;Sibuet et al, 1995;Pérez-Gussinyé and Reston, 2001). It has been used to characterize the structure of the simpleshear asymmetric extensional models (Boillot et al, 1995;Reston et al, 1995;Sibuet et al, 1995) as well as the continental-oceanic boundary (Beslier et al, 1993;Henning et al, 2004) and the rift-drift transition in the evolution of a rifted margin (Whitmarsh and Wallace, 2001;Pérez-Gussinyé et al, 2006).…”

Section: Geological Settingmentioning

confidence: 99%