Anthropogenic shell accumulations (shell middens), often of great size, occur in their tens of thousands around the world’s coastlines. They mostly date from the Mid-Holocene onwards and are frequently taken as symptomatic of a Postglacial ‘revolution’ involving world-wide population growth and intensification in exploitation of marine resources. However, the comparative rarity of earlier deposits may have as much to do with Postglacial sea-level rise and the loss of evidence from earlier palaeoshorelines as with genuine socio-economic trends. Here we investigate the underwater Mesolithic (Ertebølle) shell midden of Hjarnø Vesterhoved in Denmark, one of the first underwater shell middens to be systematically verified as an anthropogenic shell deposit in a region world-famous for its many hundreds of Ertebølle shell mounds on the present shoreline. We show how a combination of geophysical survey, coring, excavation, stratigraphic interpretation and macroscopic analysis of midden contents can be used to identify underwater deposits, to unravel their taphonomic and post-depositional history in relation to surrounding sediments, and to distinguish between cultural and natural agencies of shell accumulation and deformation. We demonstrate the presence of an intact underwater shell-midden deposit dated at 5400–5100 cal BC, one of the earliest in Denmark. We demonstrate the usefulness of such material in giving new information about early coastal subsistence economies and greater precision to the measurement of palaeo-sea levels. We discuss the implications of our results for an improved understanding of the Mesolithic record in Denmark and of biases in the archaeological record of Late Pleistocene and Early-to-Mid Holocene coastal contexts. We emphasise the importance of researching more fully the geomorphological and taphonomic processes that affect the accumulation, destruction, burial, preservation and visibility of underwater archaeological deposits, the need to extend underwater investigations more widely and to more deeply submerged palaeoshorelines, and the combination of methods required to advance such investigations.

人为的贝壳堆积物（贝壳中部）通常很大，分布在世界各地的海岸线上，成千上万。它们主要是从全新世中期开始的，经常被认为是冰川后“革命”的征兆，涉及世界范围内的人口增长和海洋资源开发的集约化。但是，较早的沉积物的相对稀有性可能与冰川后的海平面上升以及较早的古海岸线失去证据以及真实的社会经济趋势有关。在这里，我们研究了丹麦HjarnøVesterhoved的水下中石器时代（Ertebølle）贝壳中层，这是目前世界闻名的该地区成百上千个Ertebølle贝壳丘被系统确认为人为贝壳沉积物的第一个水下贝壳中层动物海岸线。我们展示了如何结合地球物理调查，取芯，开挖，地层解释和中层内容的宏观分析，来识别水下沉积物，揭示其与周围沉积物有关的沉积学和沉积后历史，以及如何区分文化特征和沉积特征。壳的自然积累和变形机构。我们证明了完整的水下壳中沉积物存在于公元前5400-5100 cal，这是丹麦最早的沉积物之一。我们证明了这种材料在提供有关早期沿海生计经济的新信息以及更精确地测量古海平面方面的有用性。我们讨论了我们的结果对更好地了解丹麦的中石器时代的记录以及晚更新世和全新世早期至中期中期沿海考古记录中的偏见的意义。我们强调，必须充分研究影响水下考古沉积物的积累，破坏，埋葬，保存和可见性的地貌和大气过程，必须更广泛地开展水下调查，并扩大到更深的古海岸线，并结合多种方法要求进行此类调查。