Lateglacial and Holocene coastal evolution in the Minho estuary (N Portugal): Implications for understanding sea-level changes in Atlantic Iberia

Abstract

The absence of accurate sea-level index points in SW Europe has long precluded the development of Holocene sea-level curves and the correct understanding of tectonic activity. In order to understand the coastal evolution and the major drivers in the Minho area, Portugal, we have combined micropaleontological and sedimentological data, where the chronological framework is provided by 13 radiocarbon ages. The stratigraphic reconstruction is in agreement with regional models of evolution and provides new sea-level index points that support a regional isostatic model producing the first complete Holocene sea-level curve from this area. Field data and model reconstructions present a good agreement for the region considered and vertical land movement estimates derived from the isostatic model are in agreement with GPS vertical velocities. At regional scale, our results support a north–south trend for SW Europe, where isostatic rebound seems to be minimized in the south of the Iberian Peninsula while local factors (sedimentation, local geomorphology, etc.) tend to dominate during the late Holocene. This newly produced sea-level curve has helped to improve isostatic model predictions and provide pre-anthropogenic sea-level rise rates against which modern rates can be compared.