The Arrábida Chain: The Alpine Orogeny in the Vicinity of the Atlantic Ocean

Abstract

The Arrábida Chain is one of the finest structural examples of the Alpine orogeny in Portugal. Placed along the south-western coast of the Setubal Peninsula, it presents one of the most spectacular coastal geomorphological settings in Portugal, with vertical sea cliffs with over 150 m plunging into the Atlantic Ocean. Due to its geographical position, post-Miocene landscape evolution was essentially a response to base-level change imposed by Neogene sea-level fluctuations, tectonic uplift of the Arrábida Chain and subsidence of the lower Tagus basin. Strong contrasts in bedrock erodibility played a crucial role in landscape evolution by imposing limits to drainage network incision, leaving competent rock bodies in clear association to the highest sector of the chain.