Cenozoic deformational structures on the Galicia Bank Region (NW Iberian continental margin)

Vázquez, Juan Tomás; Medialdea, Teresa; Ercilla, Gemma; Somoza, Luı́s; Estrada, Ferrán; Fernández-Puga, M.C.; Muset, Josep Gallart; Gràcia, Eulália; Maestro, Adolfo; Sayago, M.

doi:10.1016/j.margeo.2007.09.014

Cited by 47 publications

(62 citation statements)

References 55 publications

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“…The enriched metals (e.g., Mn, Co, Ni, Pb, Mo, and Tl) in the nodules and stratabound layers may have been carried by these ascending fluids. The system of faults generated as a response to the Cenozoic reactivation during the Pyrenean orogeny, which also affected Galicia Bank [ Vázquez et al ., ], would have provided the conduits for hydrothermal circulation that leached the basement rocks.…”

Section: Discussionmentioning

confidence: 99%

“…The seismic‐defined chimneys crosscut sedimentary Unit U1, the D1 unconformity, and partially Unit U2. Even though it is difficult to discern on the seismic profiles, the seismic chimneys appear to be rooted in semitransparent acoustic facies interpreted to be black shale [ Vázquez et al ., ; Vázquez et al ., ]. A black shale at the base of the postrift Units (Albian‐Cenomanian in age) has been described from Galicia Bank and surrounding regions [ Boillot and Malod , ].…”

Section: Discussionmentioning

confidence: 99%

“…Several morpho‐tectonic structures testify to tectonic reactivation of Galicia Bank during the Cenozoic [ Vázquez et al ., ]: (1) faults inherited from the Cretaceous propagating rift (reactivated and non‐reactivated), including reactivated normal (N‐S, NW‐SE) and strike‐slip (NE‐SW) faults, and (2) Structures resulting from episodes of compression during the Paleogene to late Miocene and late Miocene to present, including (a) late Miocene‐Quaternary normal faults, (b) folds, flexures, and (c) reverse faults (NE‐SW to ENE‐SWS). The reactivation phase along the NW flank produced 3500 m relief parallel to reverse faults and normal to the main convergence.…”

Section: Geological and Hydrographic Frameworkmentioning

confidence: 99%

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Phosphorites, Co‐rich Mn nodules, and Fe‐Mn crusts from Galicia Bank, NE Atlantic: Reflections of Cenozoic tectonics and paleoceanography

González

Somoza

Hein

et al. 2016

Geochem Geophys Geosyst

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A wide variety of marine mineral deposits were recovered from 750 to 1400 m water depths on Galicia Bank, Iberian margin. Mineral deposits include: (1) carbonate fluorapatite phosphorite slabs and nodules that replaced limestone and preserved original protolith fabric. (2) Ferromanganese vernadite crusts with high Mn and Fe (Mn/Fe = 1) contents, and thick stratabound layers consisting mainly of Mn (up to 27% MnO) and Fe (15% Fe2O3), which impregnated and replaced the phosphorite. (3) Co‐rich Mn nodules are composed of romanechite and todorokite laminae. Mn‐rich layers (up to 58% MnO) contain up to 1.8% Co. (4) Goethite nodules with Fe up to 67% Fe2O3 have low Mn and trace metals. We interpret this mineralization paragenesis to be related to major changes in oceanographic and tectonic regimes. Three phosphatization generations formed hardgrounds dated by 87Sr/86Sr isotopes as late Oligocene, early Miocene, and latest early Miocene. During the latest early Miocene, the hardground was fractured and breached due to regional intraplate tectonism, which was coeval with a widespread regional erosional unconformity. The stratabound layers and Co‐rich manganese nodules were derived from low‐temperature geothermally driven hydrothermal fluids, with fluid conduits along reactivated faults. During middle and late Miocene, the introduction of vigorous deep water flow from the Arctic generated growth of hydrogenetic ferromanganese crusts. Finally, growth of diagenetic Fe‐rich nodules (late Pliocene) was promoted by the introduction of hypersaline Mediterranean Outflow Water into the Atlantic Ocean.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Geological and Hydrographic Frameworkmentioning

confidence: 99%

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Phosphorites, Co‐rich Mn nodules, and Fe‐Mn crusts from Galicia Bank, NE Atlantic: Reflections of Cenozoic tectonics and paleoceanography

González

Somoza

Hein

et al. 2016

Geochem Geophys Geosyst

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“…The oceanic crust accretion continued in the Bay of Biscay until Santonian times (Srivastava et al, ). Afterward, the roughly N‐S compressional tectonic stress field taking place during the Alpine orogeny (since the Late Santonian to Oligocene‐Miocene times; e.g., Capote et al, ; Thinon et al, ; Tugend, Manatschal, & Kusznir, ) leads to the reactivation and partial inversion of previous rift structures, and some new compressional structures were also generated, such as thrusts, reverse faults, folds, and flexures (e.g., Grimaud et al, ; Murillas et al, ; Tugend et al, ; Vázquez et al, ).…”

Section: Regional Settingmentioning

confidence: 99%

Crustal Structure and Continent‐Ocean Boundary Along the Galicia Continental Margin (NW Iberia): Insights From Combined Gravity and Seismic Interpretation

et al. 2018

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The magma-poor rifted continental margin of Galicia has an extremely complex structure. Its formation involved several rifting episodes that occurred ultimately during the early Cretaceous near a ridge triple junction, which produced a change in the orientation of the main structures in its transition to the north Iberia margin. In addition, there is a superimposed partial tectonic inversion along its northwest and northern border which developed from the Late Cretaceous to at least Oligocene times. The present study integrates a large volume of new geophysical information (mainly marine gravity data and 2-D seismic reflection profiles) to provide insights on the formation of this rift system and on the development of its later inversion. The combined interpretation and modeling of this data enable the presentation of a new crustal and structural domain map for the whole Galicia margin. This includes the rift domains related to the extreme thinning of the crust and the lithospheric mantle (stretched, necking, and hyperextension and mantle exhumation domains), as well as a domain of intense compressional deformation. New constraints arise on the origin, the deep structure, and the characterization of the along-and across-strike variation of the continent-ocean transition of the margin, where a progressive change from hyperextension to partial inversion is observed. The development of both rifting and later partial tectonic inversion is influenced by the existence of former first-order tectonic features. Most of the tectonic inversion is focused on the hyperextension and mantle exhumation domain, which in some areas of the northwestern margin is completely overprinted by compressional deformation.

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“…The study of the seafloor geomorphology and seascapes, within the Iberian Peninsula, has been undertaken under different perspectives: geological and geomorphological maps of Spain and the Geomorphology 118 (2010) [314][315][316][317][318][319][320][321][322][323][324][325][326][327][328][329] continental margin (IGME, 2005); the Prestige oil-spill area Vázquez et al, 2008); seascape-shaping mechanisms (Amblas et al, 2006); morphosedimentary features ; identification of sedimentary features, associated with river discharges (Lobo et al, 2006;Liquete et al, 2007); or rifting (Muñoz et al, 2008). In turn, high quality information on the geology, geomorphology and seafloor characteristics of the southeastern part of the Bay of Biscay (incorporating the Basque continental shelf) is scarce, even absent.…”

Section: Introductionmentioning

confidence: 99%

Morphological characteristics of the Basque continental shelf (Bay of Biscay, northern Spain); their implications for Integrated Coastal Zone Management

et al. 2010

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Cenozoic deformational structures on the Galicia Bank Region (NW Iberian continental margin)

Cited by 47 publications

References 55 publications

Phosphorites, Co‐rich Mn nodules, and Fe‐Mn crusts from Galicia Bank, NE Atlantic: Reflections of Cenozoic tectonics and paleoceanography

Phosphorites, Co‐rich Mn nodules, and Fe‐Mn crusts from Galicia Bank, NE Atlantic: Reflections of Cenozoic tectonics and paleoceanography

Crustal Structure and Continent‐Ocean Boundary Along the Galicia Continental Margin (NW Iberia): Insights From Combined Gravity and Seismic Interpretation

Morphological characteristics of the Basque continental shelf (Bay of Biscay, northern Spain); their implications for Integrated Coastal Zone Management

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