FIELD TRIP – HOLOCENE EVOLUTION OF ARMAÇÃO DE PÊRA EMBAYMENT AND ALCALAR ARCHAEOLOGICAL COMPLEX
The meeting will be followed by an excursion to Armação de Pêra Embayment and Alcalar Archaeological Complex on Monday the 23th October with a lunch and transport provided. Spaces on the excursion will be limited and participants are encouraged to register early.
ARMAÇÃO DE PÊRA EMBAYMENT
In Armação de Pêra Bay, southern Portugal, environmental changes during the Holocene can be interpreted based on the morphological and sedimentological similarities between older morph-sedimentary features (beachrock and aeolianites) and present ones. During the Holocene, the bay has acted alternately as a positive cell dominated by constructive processes, and as a negative cell dominated by erosive processes. Its behaviour depends on sea level fluctuations and on variations in fluvial sedimentary input. During the rapid sea level rise between about 8 800 and 6 600 yr cal BP, the bay changed from a positive to a negative budget littoral cell and transgressive dunes formed, favoured by drought conditions. At about 5 000 yr cal BP, during a sea level maximum, beach width was less than the critical fetch and dunes stabilized and underwent cementation during the wetter Atlantic climatic event. The second phase of dune accumulation started at about 3 200 yr cal BP, due to a seaward migration of the shoreline during which the bay changed back to a positive budget littoral cell in which beach width was greater than the critical fetch. Currently, the beach width is less than the critical fetch, dunes are inactive, and the sedimentary budget is negative due to sediment storage in local river systems.
ALCALAR ARCHAEOLOGICAL COMPLEX
The Alcalar Chalcolithic Thorp is situated close to the city of Portimão, and presents two main areas. A large group of megalithic burial mounds of Alcalar of about 5,000 years, organized in various groupings, constitute a necropolis located in the immediate vicinity of a former housing cluster, whose ruins extend over an area of about 20 hectares. Discovered and explored since the end of the 19th century, the monuments are classified as National Monument. A part of the burial mounds is open to public visits and has an Interpretive Center. The monuments of the eastern mounds cluster of the megalithic necropolis are musealized and can be visited. The monuments of the central mounds cluster are situated on public grounds and are also accessible to visitors.