Marine organisms as markers in the site formation processes of a shipwreck from the 7th century BCE

Abstract

The ceramic cargo of the Phoenician shipwreck (Gozo) is covered by encrusted marine organisms that have accumulated over ~2 700 years. This research identifies and characterizes these benthic communities and presents a new method that advances their role as records of spatial and environmental data, which is subsequently used to inform site formation processes and supplement archaeological interpretation. Four amphorae (A18, A24, A06, and A40) were selected from different positions across the site and the variation in their associated biological communities was quantified using 92 different 10x10cm test squares. A total of 4,121 individual organisms representing 28 unique species were recorded. These included Anthozoa, Bryozoa, Foraminifera, Mollusca – Bivalvia, and Mollusca – Vermetidae. The organisms were found to be un-evenly distributed across the artifact surfaces and could be divided into five visually and compositionally distinct growth phases. This biological data was then linked with its spaAal context. Artifacts were laser scanned with coded markers on their surface and integrated into a composite 3D model of the site derived from multiple years’ worth of photogrammetric models. This method contextualized the distinct growth phases and allowed for the interpretation of artifact movement. A18, A24, and A06 were found to have been very stable over Ame. Their growth phases run mostly parallel to each other and to the seabed. Abrasion from neighboring artifacts is localized and indicative of consistency in orientation. A40 was not consistent with the others and likely represents a case of major post-depositional movement. It was found to be located in a channel bisecting the wreck and in proximity to other artifacts (notably A97) where movement was also identified. By identifying different types of movement through the study of marine benthos, this dissertation has demonstrated the effectiveness of a new method for the study of site formation processes and underwater archaeological interpretation.