Resolving Late Cretaceous intra-plate magmatism emplacement models and plate motion on the West Iberian Margin

The West Iberian Margin (WIM) was a locus of significant post-rift Late Cretaceous magmatism coeval with multiple intraplate magmatic events on the Central-North Atlantic. The effects of the migration of the Iberian microplate on the location of the distinct magmatic occurrences are here investigated.

At the WIM and within this magmatic cycle, the Sintra, Sines and Monchique intrusive massifs, the Lisbon Volcanic Complex and distinct sill complexes were emplaced on the onshore continental margin. Several coeval oceanic seamounts, are also evaluated in terms of age and location for the assessment of how plausible the combined effects of plate motion and underlying mantle contributions are to their origin.

Using GPlates software we assess the different mantle mechanisms that can explain magmatic upwelling in the region, including: 1) plume, whether static or mobile ones; 2) edge-driven convection; or 3) stationary superplume with secondary plumelets.

The preliminary results suggest that a stationary superplume emitting distinct secondary plumelets is the preferred model for the distinct and diachronous magmatic features that pierced the crust as the Iberian microplate moved along a non-linear path.

 

This work was funded by the Portuguese Fundação para a Ciência e a Tecnologia (FCT) I.P./MCTES through national funds (PIDDAC) – UIDB/50019/2020- IDL and UIDB/04035/2020- GeoBioTec.