ICG2022-358, updated on 20 Jun 2022
10th International Conference on Geomorphology
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Marine terrace staircases of western Iberia: uplift rate patterns from rocky limestone coasts of central Portugal (Cape Espichel and Raso)

António Antunes Martins1, Margarida Porto Gouveia2, Pedro Proença Cunha2, Alberto Gomes3, Christophe Falguères4, Pierre Voinchet4, Martin Stokes5, Bento Caldeira6, João Cabral7, Jan-Pieter Buylaert8, Andrew S. Murray9, Jean-Jacques Bahain4, Silvério Figueiredo10, and Pu Yang2
António Antunes Martins et al.
  • 1University of Évora, Department of Geosciences; ICT – Institute of Earth Sciences; Portugal; aam@uevora.pt
  • 2University of Coimbra, MARE - Marine and Environmental Sciences Centre, Department of Earth Sciences, Coimbra, Portugal . mariamporto@gmail.com;; pcunha@dct.uc.pt
  • 3University of Porto, Department of Geography; CEGOT; Portugal; albgomes@gmail.com
  • 4Sorbonne Université, Muséum National d'Histoire Naturelle, Dép. Homme et Environnement, CNRS-UPVD; France; christophe.falgueres@mnhn.fr; pierre.voinchet@mnhn.fr; jean-jacques.bahain@mnhn.fr
  • 5School of Geography, Earth and Environmental Sciences, University of Plymouth, UK; M.Stokes@plymouth.ac.uk
  • 6University of Évora, Department of Physics, ICT – Institute of Earth Sciences; Portugal. bafcc@uevora.pt
  • 7Instituto D. Luiz (IDL), Faculdade de Ciências, Universidade de Lisboa, Campo Grande 1749-016 Lisboa; Portugal; jcabral@fc.ul.pt
  • 8Department of Physics, Technical University of Denmark, Risø Campus, Denmark. jabu@dtu.dk
  • 9Nordic Laboratory for Luminescence Dating, Aarhus University, Risø DTU, Denmark. anmu@dtu.dk
  • 10Polytechnic Institute of Tomar; Centro Português de Geo-História e Pré-História; Centro de Geociências – Univ. Coimbra, Portugal. silverio.figueiredo@ipt.pt

The Western Iberian passive margin is under compressive tectonic reactivation resulting in spatial and temporal variations in surface uplift. This uplift can be quantified in coastal settings using staircases of wave-cut platforms developed onto rocky headlands. This study focuses on two marine terrace staircases of central Portugal: Cape Raso (west of Lisbon) and Cape Espichel (western Arrábida mountain chain). Geomorphic and stratigraphic analyses identified four marine terraces above sea level at Cape Raso area and twelve at Cape Espichel. ESR and pIRIR dating were used to develop a chronological framework for the staircases, from which uplift rates were calculated.

Using the interaction between the global mean sea-level elevations in the Quaternary and the local uplift rate (Roberts et al., 2013) the marine terraces were correlated with Marine Isotope Stages (MIS). At Cape Raso, Tm1 (+38 m) corresponds to MIS 17 (712-676 ka), Tm2 (+34 m) corresponds to the MIS 15 (621-563 ka) and was reworked during the MIS 11 (399-408 ka), Tm3 (+ 22 m) correlates with MIS 13 (533-478 ka) and was reworked during the highstand of MIS 9 (330-316 ka) and Tm4 (+9 m) correlates with MIS 7 (243 -191 ka). At Cape Espichel, a correlation was found between the relative sea-level elevations of the eight lowest terraces with several MISs (MIS 5 until MIS 17). The correlation becomes unclear for terraces older than MIS 17, translating into an apparent decrease in uplift rate towards older times. Either in Cape Raso or Espichel, the terrace staircases do not correlate in all cases with sea level high stands sequentially. For instance, the palaeoshoreline elevation of MIS 11 is higher than the palaeoshoreline of MIS 13. This suggests that marine terraces have been formed by superposition of multiple sea-level fluctuations in a long-term uplift context, but with an uplift rate low enough to allow the reworking of older shorelines during subsequent MISs.

At Cape Raso, the dating of Tm2 correlated with MIS 15 allows for an estimation of an uplift rate of ~0.07 m/ka for this coast, seemingly decreasing over the last ~125 ka. At Cape Espichel, the chronological framework of Tm5 and Tm6 allows associations with MIS 15 and MIS 11, respectively. The estimated mean uplift rate from MIS 5e to MIS 17 was ~0.14m/ka. For times older than MIS 17 (up to ca. 3.7 Ma) the uplift rate was lower than during the last ~125 ka (~0.04 m/ka). The present elevations of the late Zanclean wave-cut platform, represented by the Raso Cape Platform (~100 m) and the Cape Espichel (up to ~220 m) platforms, further express the differential uplift between the study areas for the last ~3.7 Ma.



Roberts, G.P., Meschis, M., Houghton, S., Underwood, C., Briant R.M., 2013. The implications of revised Quaternary paleo-shoreline chronologies for the rates of active extension and uplift in the upper plate of subduction zones. Quaternary Science Reviews 78, 169-187.

How to cite: Antunes Martins, A., Porto Gouveia, M., Proença Cunha, P., Gomes, A., Falguères, C., Voinchet, P., Stokes, M., Caldeira, B., Cabral, J., Buylaert, J.-P., S. Murray, A., Bahain, J.-J., Figueiredo, S., and Yang, P.: Marine terrace staircases of western Iberia: uplift rate patterns from rocky limestone coasts of central Portugal (Cape Espichel and Raso), 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-358, https://doi.org/10.5194/icg2022-358, 2022.