Underwater Shell Middens: Excavation and Remote Sensing of a Submerged Mesolithic site at Hjarnø, Denmark

Abstract

Shell middens, or shell-matrix deposits, occur in large numbers across the coastlines of the world from the mid-Holocene (ca. 6000-5000 cal BC) onwards, often forming substantial mounds. However, they become smaller, rarer or absent as one goes back into earlier periods, suggesting a worldwide process of economic intensification. Since sea level was generally much lower during these earlier periods, a critical question is the extent to which mounded shell middens could have accumulated on now-submerged palaeoshorelines, and if so, how they were affected by the potentially destructive impact of sea-level rise. Further, and important to modern practice, it is essential that archaeologists consider how such sites can be discovered through underwater investigation. Here we offer a proof of concept that shell middens can survive submergence and can be detected, using systematic investigation of a rare example of a confirmed underwater shell midden at the Mesolithic site of Hjarnø (ca. 5300-4300 cal BC) in Denmark. We

New paradigms in the exploitation of Mesolithic shell middens in Atlantic France: The example of Beg-er-Vil, Brittany

“…The exceptional preservation conditions also attracted faunal specialists at a time when French archaeozoology was undergoing profound methodological renewal (Tresset, 2000(Tresset, , 2002(Tresset, , 2003(Tresset, , 2005aGruet, 2002;Dupont and Gruet, 2005;Dupont, 2006;Dupont et al, 2009, J o u r n a l P r e -p r o o f 2010). Such combination of archaeological and paleo-environmental disciplines were initiated in other shell middens of the Atlantic Europe earlier (Mellars, 1978(Mellars, , 1987Andersen and Johansen, 1986) or at the same time as in France Bicho et al, 2010;O'Sullivan and Breen, 2011;Andersen, 2013;Gutiérrez-Zugasti et al, 2013, 2014Bicho et al, 2015;Arias et al, 2017;Moe Astrup et al, 2019). The descriptions of shell middens in Brittany during the first half of the 20 th century were influenced by the image associated with prehistoric populations, as the past excavations at Téviec and Hoedic focused on human bones and ignored the marine molluscs.…”

The Kalvestene: A reevaluation of the ship settings on the Danish island of Hjarnø

“…Situated just off the coast of Jutland, the small island of Hjarnø's location has many natural and strategic advantages (Figure 1). While the water offers a barrier to attack, Hjarnø is still close to mainland resources (Larsen et al 2018;Astrup et al 2020). It also guards the entrance to Horsens Fjord and the port connected with the medieval trading center at Horsens (Kelmelis and Pedersen 2019).…”

“…Archaeological evidence shows continued occupation of Hjarnø through the Germanic Iron Age, Viking period and High Middle Ages, including the remains of a first century structure, perhaps a boathouse (Smeklova 2009), a significant hoard of deposited high-status sixth century artifacts (Ravn 2019), and a late medieval church, in addition to the Viking Age Kalvestene ship settings. While there is evidence of Mesolithic activity on the island which centers on the western coast (Astrup et al 2020), sites dating from after the introduction of agriculture are concentrated on the southern coast. One section of this coast was once known as the "Kalvestene," "the calf stones," (from which the ship settings were named) because the land is not arable and so was used for grazing livestock.…”

Integrating Aerial and Underwater Data for Archaeology: Digital Maritime Landscapes in 3D

“…A Mesolithic site located on the island Hjarnø (Astrup et al 2019;Skriver et al 2017) represents an outstanding opportunity to integrate multi-scalar 3D recording techniques and present a complex site in high resolution. This is important because submerged material from Denmark has been recorded for several decades using traditional archaeological recording methods.…”

“…These datasets were then merged into a single 3D environment in GIS and in the 3D modelling software Blender, with floating surveys georeferenced using the total station dGPS survey. Further work is ongoing to integrate the results of coring and excavation both at the site itself and in the wider landscape (Astrup et al 2019).…”