Geological and cultural routes of the Brecha da Arrábida: a contribution to the candidature of Arrábida for UNESCO's Mixed World Heritage List

The Upper Oxfordian Brecha da Arrábida is a unique lithological type in Portugal and probably inthe world because it was formed through several particular geological influences acting simultaneously. The rock is aconglomerate composed of carbonate pebbles of different colours, cemented by a red, ferruginous, clayey carbonate. Itis the expression of fossilized a karst that marks one of the major unconformities of the Lusitanian Basin, whichwas associated with the early stages of the opening of the North Atlantic. One of the strengths of the candidatureof Arrábida for UNESCO's Mixed World Heritage List is the intimate connection between the natural environment,particularly the landscape (Criterion VII) and the geology and geomorphology (Criterion VIII), and the historyand culture of the region and country. The natural occurrences of Brecha da Arrábida, the exploration of which endedin 1975 with the creation of the Natural Park, are rare and sporadic. The geographical dispersion of outcrops willnecessitate the creation of scientific and cultural routes to facilitate visits by the millions of tourists who travel to theArrábida region each year. The creation of routes in the region is, therefore, one of the objectives of this candidature.In addition, the Brecha da Arrábida conglomerate has been used for ornamental purposes since the late fifteenthcentury, and was used for the first sculptural and decorative expressions of the so-called Portuguese Late Gothic andManueline styles, and later in the Baroque because of its colourful varieties. This artistic use of the Brecha daArrábida, as well as other uses of the material, extends far beyond the actual geographical area of Arrábida. This widersignificance provides part of the justification for building a website where users can add information regarding the usesof Brecha da Arrábida in both Portugal and other countries, thereby updating the existing features of Arrábida, and isviewed as a vital component for disseminating knowledge about geology to the public.