Integrated thematic geological mapping of the Atlantic Margin of Iberia

Terrinha, Pedro; Medialdea, Teresa; Batista, Luís; Somoza, Luı́s; Magalhães, Vítor; González, Francisco Javier; Noiva, João; Lobato, Ana B.; Rosa, Marcos; Marino, Egidio; Brito, Pedro; Neres, Marta; Ribeiro, Carlos

doi:10.1144/sp505-2019-90

Cited by 8 publications

(7 citation statements)

References 103 publications

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“…The Atlantic Margin of Iberia encompasses three different tectonic sectors, the West Iberia Margin (WIM), the North Iberia Margin (NIM) and the SW Iberia Margin (SWIM) that formed as a result of rifting and seafloor spreading of the North Atlantic Ocean, Bay of Biscay and Western Tethys Ocean, respectively. Iberia shows widespread evidence of the Alpine orogeny both in the Paleozoic basement and in the Mesozoic rift basins, as well as major intra-oceanic compressional tectonic structures, mostly of Cenozoic age structures (Terrinha et al, 2020(Terrinha et al, , 2019. Present-day active subduction in the SWIM (in relation with subducted slab beneath the Gibraltar Arc) is still a matter of discussion (Gutscher et al, 2002;Terrinha et al, 2020;Zitellini et al, 2009).…”

Section: Geological Setting and Geomorphologymentioning

confidence: 99%

Magnetic and gravimetric modeling of the Monchique magmatic intrusion in south Portugal

Camargo

Neres

Bos

et al. 2022

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The Monchique alkaline complex (MAC) crops out in southern Portugal with a roughly elliptical shape of about 80 km2 elongated along ENE-WSW direction. The MAC dates to Late Cretaceous (69-72 Ma) and intrudes the Carboniferous Flysh formation of the South Portuguese Zone. At the surface, it comprises two main types of syenites: a central homogeneous nepheline syenite surrounded by a heterogeneous syenite unit, and some less expressive outcrops of mafic rocks (gabbros, hornfels, breccia and basalts). This igneous complex belongs to the Upper Cretaceous West Iberia alkaline magmatic event, characterized by alkaline magmatism of sublithospheric origin and active from approximately 100 Ma to 69 Ma.The Monchique region hosts the most active seismic cluster of mainland Portugal, with low magnitude earthquakes (M < 4) that occur along lineations with NNE&#8211;SSW and WNW&#8211;ESE preferred orientation.In this work we study the Monchique region through gravimetric and magnetic methods in order to: 1) better understand how the MAC influences the geomagnetic and gravimetric field in the region; 2) to create a new and consistent 2D and 3D model for the intrusion; and 3) to help constraining the origin of the observed seismicity and its possible relation with the existence of subcropping magmatic bodies.We process recently acquired data - ground gravity survey (49 points) and drone-borne aeromagnetic survey &#8211; and integrate it with existing data. The interpretation of gravimetric results is complemented by density analysis of magmatic and host rocks. We perform 3D magnetic and gravity inversion to model the geometry of gravity and magnetic sources, and 2D magnetic forward modeling along a representative profile.The calculated Bouguer gravity anomaly shows a positive gradient towards the southwest with a negative peak in the center of the Monchique mountain. However, when applied the terrain correction (complete Bouguer anomaly), this peak vanishes. This is justified by the similar mean density values for the syenite and host rocks, respectively 2560 kg/m3 and 2529 kg/m3.The new aeromagnetic data allows for mapping the Monchique magnetic anomaly with unprecedented detail and reveal a 10 km elongated anomaly with 30 m wavelength with maximum 1707 nT amplitude. 3D susceptibility inversion models show a 15km long body with maximum depth between 5-10km, and susceptibility >0.02 SI, in agreement with previous susceptibility analysis in the region. The highest magnetic signal is found at Picota hill (east), but the deepest parts of the intrusion seem to be bellow Foia hill (west). It is noteworthy that earthquake hypocenters concentrate at depths of 5-20 km, thus below most of the modeled magmatic intrusion. &#160;This work was developed for the MSc thesis of GCC, in the frame of ATLAS project (PTDC/CTA-GEF/31272/2017), POCI-01-0145-FEDER-031272, FEDER-COMPETE/POCI 2020) partly funded by FCT. FCT is further acknowledged for support through projects UIDB/50019/2020-IDL, PTDC/CTA-GEF/1666/2020 and PTDC/CTA-GEF/6674/2020.

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Section: Geological Setting and Geomorphologymentioning

confidence: 99%

Magnetic and gravimetric modeling of the Monchique magmatic intrusion in south Portugal

Camargo

Neres

Bos

et al. 2022

Preprint

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“…Together with the assessment of the European seabed, new potential sources of supply are identified. As part of the European Marine Observatory and Data Network (EMODnet), MINDeSEA adds to the comprehensive information of Europe’s maritime issues [ 90 ].…”

Section: Principles On the Availability From Eu Sourcesmentioning

confidence: 99%

The Critical Raw Materials Issue between Scarcity, Supply Risk, and Unique Properties

et al. 2021

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This editorial reports on a thorough analysis of the abundance and scarcity distribution of chemical elements and the minerals they form in the Earth, Sun, and Universe in connection with their number of neutrons and binding energy per nucleon. On one hand, understanding the elements’ formation and their specific properties related to their electronic and nucleonic structure may lead to understanding whether future solutions to replace certain elements or materials for specific technical applications are realistic. On the other hand, finding solutions to the critical availability of some of these elements is an urgent need. Even the analysis of the availability of scarce minerals from European Union sources leads to the suggestion that a wide-ranging approach is essential. These two fundamental assumptions represent also the logical approach that led the European Commission to ask for a multi-disciplinary effort from the scientific community to tackle the challenge of Critical Raw Materials. This editorial is also the story of one of the first fulcrum around which a wide network of material scientists gathered thanks to the support of the funding organization for research and innovation networks, COST (European Cooperation in Science and Technology).

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“…Iberia is located on the Eurasian plate, just north of the African-Eurasia plate boundary at the easternmost termination of the Azores-Gibraltar Fracture Zone (Purdy 1975) (Figure 1). The modern physiographic features of the offshore West Iberian Margin (WIM) are determined by the main tectonic events that followed the breakup of Pangea, the Mesozoic rifting, the Atlantic seafloor spreading and the Cenozoic shortening and compressive reactivation of the Portuguese Margin (Alves et al 2003;Terrinha et al 2020) and interactions with long-lasting oceanic bottom currents (Hernandez-Molina et al 2003)…”

Section: Physiographic Overviewmentioning

confidence: 99%

“…The Estremadura Spur is a major tectono-morphic feature where the continental slope gently dips westward at a constant gradient of 4º from 300 to 3000 m depth (Badagola 2008). To the north and south of the spur the shelf and slope show clear marks of vertical erosion and regional slope gradients reach up to 13º (Alves et al 2003;Terrinha et al 2020).…”

Section: Continental Shelf and Slopementioning

confidence: 99%

Spatial and morphometric relationships of submarine landslides offshore west and southwest Iberia

Gamboa¹,

Omira²,

Terrinha³

2021

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Submarine landslides are ubiquitous geohazards in marine environments occurring at multiple scales. Increasing efforts have been made to catalogue and categorise submarine landslides in comprehensive databases, aiming to better understand their preconditioning and trigger factors. Using the recently compiled, open-access MAGICLAND dataset, we investigate the distribution and morphometric trends of submarine landslides observed in seven distinct geomorphologic domains offshore west and southwest Iberia. In the study area, the higher densities of submarine landslides occur on the proximal southwest margin, with higher frequency nearby earthquake epicentre clusters recorded in the area. Submarine canyons are another major location for slope collapses, with a prevalence for their mouth regions. However, relevant numbers occur within all domains with important relief, including distal regions hundreds of kilometres away from the foot of the continental slope. Landslide size range is inversely proportional to their spacing and frequency within each domain, and within the whole study area. Relevant positive correlations were obtained between the parameters analysed, but relationships between unidimensional parameters such as length and width exhibit the lower correlation coefficient. Correlations of 2D and 3D parameters such as area and volume provide better results, aligning with prior observations. The relationships obtained are, however, variable across domains and the correlation values are influenced by the seafloor geomorphology. This work brings new insights on submarine landslide distribution in the understudied west and southwest Iberian continental margin, complements previous inventories made for nearby regions, and provides valuable data with wider applications for submarine landslide databases.

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Integrated thematic geological mapping of the Atlantic Margin of Iberia

Cited by 8 publications

References 103 publications

Magnetic and gravimetric modeling of the Monchique magmatic intrusion in south Portugal

Magnetic and gravimetric modeling of the Monchique magmatic intrusion in south Portugal

The Critical Raw Materials Issue between Scarcity, Supply Risk, and Unique Properties

Spatial and morphometric relationships of submarine landslides offshore west and southwest Iberia

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