Seismic evidence of exhumed mantle rock basement at the Gorringe Bank and the adjacent Horseshoe and Tagus abyssal plains (SW Iberia)

Sallarès, Valentı́; Martínez-Loriente, S.; Prada, Manel; Gràcia, Eulália; Ranero, César R.; Gutscher, Marc-André; Bartolomé, Rafael; Gailler, Audrey; Dañobeitia, Juan José; Zitellini, Nevio

doi:10.1016/j.epsl.2013.01.021

Cited by 78 publications

(134 citation statements)

References 62 publications

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“…The velocities from 6.8-7.2 km/s to 8.0 km/s are too low for unaltered mantle and may result from serpentinization of the upper mantle (e.g., in fracture zones, Detrick et al, 1993, the COT of nonvolcanic rifted margins, Davy et al, 2016, and slow or ultraslow spreading oceanic basins; e.g., the Labrador Sea; Delescluse et al, 2015;Osler & Louden, 1992 or magma intrusion (e.g., in NW Indian Ocean; Gupta et al, 2010). In our final model (Figure 3b), velocities at depths >3 km below the top basement sit outside the envelopes for Pacific and magmatic oceanic crust newly compiled by Grevemeyer et al (2018;Figure 9a well with the velocity profiles in the models of thin oceanic crust overlying serpentinized mantle in the North Atlantic Ocean (Figure 9b; Davy et al, 2016;Funck et al, 2003;Hopper et al, 2004;Whitmarsh et al, 1996) and the exhumed mantle zone in West Iberia (Figure 9b; Dean et al, 2000;Sallarès et al, 2013) and the Central Tyrrhenian Basin (Figure 9c; Prada et al, 2014). Serpentinization of the upper mantle is facilitated when the crust is thin and fractured to allow seawater to flow in (Minshull et al, 1998;Sauter et al, 2013;Shillington et al, 2006).…”

Section: Reflection Moho Hypothesissupporting

confidence: 64%

Seismic Evidence for Tectonically Dominated Seafloor Spreading in the Southwest Sub‐basin of the South China Sea

Yan

Wang

et al. 2018

Geochem Geophys Geosyst

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Seafloor spreading can be explained by different dynamic mechanisms, magmatically or tectonically dominated. The Southwest Sub‐basin, located at the southwest tip of the propagating seafloor spreading of the South China Sea, remains unclear for its spreading regime owing to poor and debated knowledge of the crustal structures. Here two multichannel seismic lines and one oceanic bottom seismometer line across this subbasin are reprocessed and analyzed with focus on crustal imaging. The sediments are usually 0.5–1.0 km thick over the abyssal basin and slightly thicker in the few grabens. The thickest (3.3 km) sediments are found in the fossil spreading center. The basement is fairly rough and highly faulted by ubiquitous crustal faults. The fossil spreading center is characterized by a deep median valley, similar to that of magma‐poor spreading cases. Both multichannel seismic lines show a few intermittent and diffusive reflectors at 1.5‐ to 3.6‐km depth below the fragmented basement. These reflectors, correlating well with the velocities of 6.8–7.2 km/s obtained from velocity inversion of oceanic bottom seismometer data, are interpreted as Moho reflections. Thus, the inferred crustal thickness is only 1.5–3.6 km excluding the sediments, which is much thinner than usual. The underlying mantle with velocities lower than 8.0 km/s might be serpentinized with water infiltration along these crustal faults. Therefore, it is proposed that the spreading of the Southwest Sub‐basin was tectonically dominated.

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Section: Reflection Moho Hypothesissupporting

confidence: 64%

Seismic Evidence for Tectonically Dominated Seafloor Spreading in the Southwest Sub‐basin of the South China Sea

Yan

Wang

et al. 2018

Geochem Geophys Geosyst

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“…The multibeam bathymetry merges the SWIM compilation map [ Zitellini et al ., ] and General Bathymetric Chart of the Oceans (GEBCO) digital atlas ( http://www.gebco.net/). Thick gray lines labeled P1 and P2 correspond to the WAS profiles acquired during the NEAREST‐SEIS survey [ Sallarès et al ., , ]. Yellow circles display OBS along the SE segment of the profile P1 presented in this paper (OBS18 to OBS30).…”

Section: Introductionmentioning

confidence: 99%

“…The overall objective of this work is to determine the structure and properties of the basement in the Coral Patch Ridge and Seine Hills in order to determine which is the affinity and possible origin of this geological domain. This information, which complements that obtained from WAS modeling along the rest of NEAREST‐SEIS profiles [ Sallarès et al ., , ], is key to properly understand the regional geodynamic evolution of the area from the Mesozoic to the present day. We first present the data used and methods followed to obtain the velocity and density models along the Coral Patch Ridge to Seine Hills transect.…”

Section: Introductionmentioning

confidence: 99%

Seismic and gravity constraints on the nature of the basement in the Africa‐Eurasia plate boundary: New insights for the geodynamic evolution of the SW Iberian margin

et al. 2014

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We present a new classification of geological domains at the Africa-Eurasia plate boundary off SW Iberia, together with a regional geodynamic reconstruction spanning from the Mesozoic extension to the Neogene-to-present-day convergence. It is based on seismic velocity and density models along a new transect running from the Horseshoe to the Seine abyssal plains, which is combined with previously available geophysical models from the region. The basement velocity structure at the Seine Abyssal Plain indicates the presence of a highly heterogeneous, thin oceanic crust with local high-velocity anomalies possibly representing zones related to the presence of ultramafic rocks. The integration of this model with previous ones reveals the presence of three oceanic domains offshore SW Iberia: (1) the Seine Abyssal Plain domain, generated during the first stages of slow seafloor spreading in the NE Central Atlantic (Early Jurassic); (2) the Gulf of Cadiz domain, made of oceanic crust generated in the Alpine-Tethys spreading system between Iberia and Africa, which was coeval with the formation of the Seine Abyssal Plain domain and lasted up to the North Atlantic continental breakup (Late Jurassic); and (3) the Gorringe Bank domain, made of exhumed mantle rocks, which formed during the first stages of North Atlantic opening. Our models suggest that the Seine Abyssal Plain and Gulf of Cadiz domains are separated by the Lineament South strike-slip fault, whereas the Gulf of Cadiz and Gorringe Bank domains appear to be limited by a deep thrust fault located at the center of the Horseshoe Abyssal Plain.

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“…UI is the lowest seismic unit that displays organized stratified reflections. It lays on top of acoustic basement that should correspond to oceanic crust of Late Jurassic age, according to general agreement (Seton et al, 2012;Sallarès et al, A C C E P T E D M A N U S C R I P T Inspection of available and published seismic reflection lines in the study area (see Fig. 2a for location) shows that the top of the folded horizons of UIII are covered by sediments that are lateral equivalent of the Allochthonous unit of the Gulf of Cadiz (Medialdea et al, 2004).…”

Section: The Hirondelle Seamount and The South Hirondelle Landslidementioning

confidence: 93%

Deep-water seamounts, a potential source of tsunami generated by landslides? The Hirondelle Seamount, NE Atlantic

et al. 2016

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Seismic evidence of exhumed mantle rock basement at the Gorringe Bank and the adjacent Horseshoe and Tagus abyssal plains (SW Iberia)

Cited by 78 publications

References 62 publications

Seismic Evidence for Tectonically Dominated Seafloor Spreading in the Southwest Sub‐basin of the South China Sea

Seismic Evidence for Tectonically Dominated Seafloor Spreading in the Southwest Sub‐basin of the South China Sea

Seismic and gravity constraints on the nature of the basement in the Africa‐Eurasia plate boundary: New insights for the geodynamic evolution of the SW Iberian margin

Deep-water seamounts, a potential source of tsunami generated by landslides? The Hirondelle Seamount, NE Atlantic

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