Establishing the timing, duration, and nature of shell midden deposition requires a clear understanding of site-formation processes. Archaeological soil micromorphology is the study of soils or sediments in their intact state using petrographic thin sections and polarising light microscopy. It is a powerful tool for disentangling geogenic, anthropogenic and biogenic processes, providing information and insights on site-formation not accessible at the macroscopic scale of excavation.

We are carrying out a detailed microstratigraphic study of each NeoMarE site to establish whether deposits are affected by post-depositional mixing or leeching processes and therefore suitable for lipid biomarker analysis or the recovery of materials for radiocarbon dating. This will allow us to distinguish between primary deposits (e.g. discreet tossing events, occupation surfaces) and secondary deposits (e.g. reworked, dumped), and highlight potential seasonal patterns or anthropogenic activities such as burning, cooking, trampling, or hut floor preparation, providing entirely new insights into how these sites were used in the past.

High-resolution palaeoenvironmental data is required to understand whether Neolithic marine resource use in Atlantic Europe can be linked to abrupt or adverse climate change. Sedimentary lipid biomarkers have emerged in recent years as a powerful molecular climate proxy. A key component of NeoMarE is the application of sedimentary lipid biomarker analyses to accurately correlate palaeoenvironmental and behavioural records.

A fine-grained sampling strategy is being employed to recover sediments directly from the shell midden soil micromorphology block samples. This makes it possible to link environmental and behavioural datasets at the microstratigraphic scale. Lipids extracted from these sediments are being analysed by coupled gas chromatography-combustion-isotope ratio mass spectrometry (GC/C/IRMS), providing insights into past environmental conditions. For instance, the carbon isotopic ratio (13C/12C; δ13Cwax) of n-alkanes derived from leaf waxes is a sensitive record of perturbations in the carbon cycle, local vegetation dynamics, and climate , while the ratio of deuterium to hydrogen (D/H; δ2Hwax) records fluctuations in past precipitation and hydrological regimes. The results of these analyses represent a significant contribution to the terrestrial palaeoclimate record for the study region and are helping us to better understand potential climatic drivers of prehistoric marine resource exploitation.