Geomagnetic investigations at Monte da Contenda, Arronches, Portugal – Results from the 2018 campaign

Abstract

In light of the current interest in climate change and its effects on modern economies, several projects have highlighted the role of climate forcing on past societies. In particular, there has been focus on the role of climate forcing in the Iberian Peninsula, during the 4.2 k event, which roughly coincides with the Chalcolithic to Bronze Age transition (c. 2200–2000 BCE).
While much of this research has focused on the South-eastern regions, given its long and rich history of archaeological research, some attention has shifted to the Southwest Iberia, which has revealed in recent years a clearer picture of its societies during the Chalcolithic period. More specifically, Southwest Iberia has disclosed very interesting social dynamics when it comes to ditched-enclosure sites, dynamics that came to a rather abrupt end around the same time of the 4.2 k event. The current paper reports the results of the 2018 geomagnetic survey campaign at the ditched-enclosure site of Monte da Contenda, in Arronches, Portugal. While these results are not directly related to climate forcing per se, they do provide more insight into the Chalcolithic communities that could have been directly affected by climate events.
Whereas the first campaign, in 2013, revealed a very complex ditch system but was unable to expose the site’s full layout, the 2018 campaign was able to reveal the site’s ditch systems in their entirety. Many of the assumptions established in the first campaign concerning the layout of the site were confirmed during this second campaign, namely that the ditch system is delimited to the south by the ribeira das Argamassas and that the site contains two distinct ditch systems, comprising a total of 17 to 19 ditches, establishing Monte da Contenda as the site with the highest number of ditches currently known in Portugal.