Interplay of tectonics and magmatism during post‐rift inversion on the central West Iberian Margin (Estremadura Spur)

Abstract

The combined effects of post-rift magma emplacement and tectonic inversion on the hyper-extended West Iberian Margin are unravelled in detail using multichannel 2D/3D seismic data. The Estremadura Spur, acting as an uplifted crustal block bounded by two first-order transfer zones, shows evidence of four post-rift tectonic

Nature, timing and magnitude of buried Late Cretaceous magmatism on the central West Iberian Margin

“…Despite some limitations on the dataset and the methods allowing to quantify the different rock volumes, the estimated volumes of magmatic material are not an absolute value but provide an indication of the overall magnitude of the wider event. For the ESI laccolith intrusion, Pereira et al (2021) report a total volume of 942 km 3 . From the data obtained for this study, we estimate that the sills account for ca.…”

“…Grange et al, 2010;Matton & Jébrak, 2009;Merle et al, 2019;Miranda et al, 2009). Adding to this understanding, new evidence from the subsurface, including its tectono-magmatic insights, helped to bring forward an updated view on the larger extent, significance and implications of this cycle (Neres et al, 2018;Pereira et al, 2017Pereira et al, , 2021. Building on our new observations, that include the details on the presence of a large volcanic edifice (the Fontanelas Volcano), along with lava flows and also, numerous sills and sill complexes, as part of a complex magmatic plumbing system, a discussion is herein presented, aiming to elaborate on the type, timing and magnitude of magmatism, as well as the implications for the wider WIM magmatic province, as a whole.…”

“…In the absence of any direct correlation with boreholes in the submerged area, seismic stratigraphy criteria were used to characterise the distinct depositional mega‐sequences (sensu Hubbard et al, 1985). In parallel, relative age constrain of the identified magmatic features and associated sedimentary deposits was underpinned by regional geological information of the main depositional strata in which coeval magmatism is described (Alves et al, 2009; Azerêdo et al, 2003; GPEP, 1986; Miranda et al, 2009; Pereira et al, 2021; Rey et al, 2006; Witt, 1977).…”

“…Here, the Late Cretaceous strata are strongly deformed as a result of NE–SW shortening of the margin during the Campanian‐Early Palaeocene, which resulted in generalised folding and reverse faulting, ultimately crosscut by a regional unconformity of Maastrichtian‐Danian(?) age (Martín‐Chivelet et al, 2019; Pereira et al, 2021). Tectonic inversion resumed in the Tertiary with two main pulses of shortening, by the mid‐Eocene and Oligo‐Miocene, recording the progressive rotation of the stress field towards a NW–SE direction that ultimately shaped the current geometry of the drifting margin.…”

“…Tectonic inversion resumed in the Tertiary with two main pulses of shortening, by the mid‐Eocene and Oligo‐Miocene, recording the progressive rotation of the stress field towards a NW–SE direction that ultimately shaped the current geometry of the drifting margin. Deformation in the Estremadura Spur is also affected by the emplacement of a voluminous laccolith exceeding 942 km 3 (the ESI in Escada et al, 2019; Pereira et al, 2021). This is similar to the Sintra intrusion, where folds and associated ring to radial dykes, and sills that can be observed on outcrops (Alves, 1964; Kullberg & Kullberg, 2017; Ramalho et al, 1993; Terrinha et al, 2017).…”