The impact of protective shelters on the megalithic structures of Malta : looking at the past through non-invasive approaches

Abstract

The sheltering of an archaeological site is a reversible, preventive measure that needs to be based on sound scientific data. This paper focuses on the studies that led to the sheltering of three of the UNESCO-listed Prehistoric Megalithic Structures on the Maltese Islands, including data collection and evaluation before and after the sheltering. Scientific investigations of these sites commenced in 1985 and included accurate documentation, environmental monitoring and limited sampling and analyses. Within the last four years, targeted studies have used an entirely non-invasive approach to evaluate the performance of one of the open-sided shelters, erected in 2009 over the Mnajdra site. Understanding both the state of conservation of the megaliths and the causes of their deterioration is of primary importance, as is evaluating the impact of the shelters on the micro-environment of the site. Thermal imaging, on-site chemical analyses and environmental studies are being carried out, with wind data in particular leading to the development of a 3D wind-flow numerical model. These data will be crucial in future decisions regarding conservation measures for the megaliths, including whether the preventive approach at the heart of the original decision is effective and whether any changes need to be made to the current strategy to ensure the continued preservation of these fragile sites.