Coastal shell midden deposits are a quintessential component of the archaeological record on the Pacific Northwest Coast. Despite their importance in informing the cultural and environmental histories of Indigenous peoples, research on shell middens has largely not sought to address the physical extent of these cultural deposits, which requires estimating shape, depth, and volume. Here, we present a new scalable geospatial model, designed to work with legacy survey data, for estimating midden volumes based on applying a regular geometric solid to sites with known extent and depth. We evaluate the accuracy of this technique using percussion core, total station, and lidar data from eight sites in Tseshaht territory on western Vancouver Island and three sites on the north coast of British Columbia (Canada). As part of the evaluation process of our results, we calculate uncertainty using subsurface core depth data and then compare generalized and modeled midden volume estimates. We demonstrate an accurate general model applied at the regional scale across a systematically surveyed landscape. This work presents the first landscape-scale measure of midden extents and volume within our study area, with relevance to historical ecology and settlement patterns.

This article highlights the utility of vibracore technology to sample deep shell midden deposits on the Central Pacific Coast of British Columbia, Canada. Analysis of six core samples and 21 radiocarbon dates revealed that the archaeological deposits extended to a depth of 544 cm below surface and that occupation began approximately 6,000 years ago, continuing into the sixteenth century AD. Zooarchaeological identification of fine screened (2 mm) sediments shows that fish constitute 99.8% of identified vertebrate fauna, with a focus on herring (Clupea pallasii), salmon (Oncorhynchus sp.), rockfish (Sebastes sp.), and greenling (Hexagrammos sp.), followed by a variety of other fish taxa utilized throughout the occupation of this site. Despite a much smaller examined volume relative to conventional excavation, vibracoring was effective in recovering deep, stratigraphically intact, and adequate samples of zooarchaeological fisheries data as well as a considerable number of stone, bone, and shell artifacts (an estimated 550 artifacts per cubic meter of cultural sediments). These results show a persistent and sustainable ancient fishery through six millennia until the contact period. The field and laboratory methods described are especially conducive to sampling large and deep shell midden deposits repetitively.

For most of human history, funerary burial has been unusual. Archaeology shows a shift in funerary practices in postglacial hunter-gatherers, in parts of Europe during the Late Mesolithic. This is documented by the burial grounds in the Tagus and Sado valleys in the southwestern Iberian Peninsula, Portugal, where ca. 376 burials were excavated. This study presents a chronology for the burial activity in these sites and contextualizes the start and end activity phases within regional environmental changes and cultural developments. The dataset consists of 76 14C dates on human bone (19 new, 57 published) including new dates from contexts in Portugal outside these valleys. Bayesian chronological models were defined in OxCal, and protein carbon contributions of marine foods were estimated by the Bayesian mixing model FRUITS. The results indicate a broader timeframe for the Late Mesolithic in Portugal, than previously suggested, starting during a period of significant environmental changes, ca. 8500–8300 cal BP, and ending ca. 7000 cal BP. The burial activity decreased during the establishment of Neolithic farmers in southwestern Iberia from ca. 7450 cal BP, however, these burial grounds continued to be used by Mesolithic hunter-gatherers, showing that diverse social structures and worldviews coexisted for several generations.

Coastal archaeology is vulnerable to climate change, making the development of new techniques for the rapid recovery of information from the most threatened sites essential. The authors report a systematic kayak survey of a Chesapeake Bay sub-estuary undertaken during the winter months, when low tides and reduced vegetation maximise the visibility of archaeological material. Locations in the vulnerable intertidal zone were targeted for survey. Data were collected for 24 archaeological sites, illuminating local settlement chronology. This technique could be used for the survey of endangered coastal archaeology in other regions of the world.

In coastal and island archaeology, carbonate mollusk shells are often among the most abundant materials available for radiocarbon (14C) dating. The marsh periwinkle (Littorina irrorata) is one of these such species, ubiquitously found along the Atlantic and Gulf coasts of the United States in both modern and archaeological contexts. This paper presents a novel approach to dating estuarine mollusks where rather than attempting to characterize the size and variability of reservoir effects to “correct” shell carbonate dates, we describe a compound-specific approach that isolates conchiolin, the organic matter bound with the shell matrix of the L. irrorata. Conchiolin typically constitutes <5% of shell weight. In L. irrorata, it is derived from the snail’s terrestrial diet and is thus not strongly influenced by marine, hardwater, or other carbon reservoir effects. We compare the carbon isotopes (δ13C and Δ14C) of L. irrorata shell carbonate, conchiolin, and bulk soft tissue from six modern, live-collected specimens from Apalachicola Bay, Florida, with samples that represent possible sources of carbon within their environment including surface sediments, marsh plant tissues, and dissolved inorganic carbon (DIC) in water. Ultimately, this paper demonstrates that samples obtained from wet chemical oxidation of L. irrorata conchiolin produces accurate 14C dates.

In southwestern Florida, USA, terraformed landscapes built almost entirely of oyster shells (Crassostrea virginica) reflect a unique pre-Columbian tradition of shell-built architecture. The ability to reliably date oyster shells is essential to identifying spatial, temporal, and functional relationships among shellworks sites, yet to date there has been no systematic attempt to quantify or correct for carbon reservoir effects in this region. Here we present 14 radiocarbon (14C) ages for 5 known-age, pre-bomb oyster shells collected between AD 1932–1948, as well as 6 14C ages for archaeological oyster/charcoal pairs from the Turner River Mound Complex, Everglades National Park. We report our current best estimate of ΔR = 92 ± 74 yr for Greater Southwest Florida, and ΔR = –15 ± 42 yr for the Turner River archaeological site. Future research should focus on paired archaeological specimens to obtain spatially and temporally relevant estimates of ΔR.

Archaeological fieldwork at Hjarnø Sund in Horsens Fjord (eastern Jutland, Denmark) has explored an eroding Mesolithic shell midden. Its stratigraphy is characterized by two layers, containing marine mollusk taxa typically collected by Mesolithic hunter-gatherers for food. In the field, the lower layer appeared to be dominated by oysters (Ostrea edulis), while the upper one by cockles (Cerastoderma edule), which was confirmed by our zooarchaeological study. Accelerator mass spectrometry radiocarbon (AMS 14C) dating on shells and paired charcoal samples from the two layers indicate that these are chronologically consecutive (separated by as little as 0–163 yr [95.4%]) and that the oyster-to-cockle shift dated between ~5500–5300 and ~5300–5200 cal BC (around or just after the Kongemose/Ertebølle transition). The shell midden at Hjarnø Sund is, thus, one of the oldest-known in Denmark, demonstrating that intensive shellfish exploitation was a hallmark of the Ertebølle culture from its inception. Oyster-to-cockle shifts, thus, also occurred at times other than the Mesolithic–Neolithic Transition and may have been ultimately caused by local shoreline displacements, resulting from changes in sedimentation, possibly induced by drops in relative sea level.

Prince Rupert Harbour (PRH), on the north Pacific Coast of British Columbia, contains at least 157 shell middens, of which 66 are known villages, in an area of approximately 180 km2. These sites span the last 9500 yr and in some cases are immense, exceeding 20,000 m2 surface area and several meters in depth. Recent archaeological research in PRH has become increasingly reliant on radiocarbon dates from marine shell for developing chronologies. However, this is problematic as the local marine reservoir effect (MRE) remains poorly understood in the region. To account for the MRE and to better date the Harbour’s sites, we propose a ΔR of 273±38 for the PRH area, based on our work at the site of Kitandach (GbTo-34), a massive shell midden-village centrally located within the Harbour. We followed the multiple paired sample approach for samples from specific contexts and ensured contemporaneity within the groups of marine and terrestrial materials by statistically assessing for outliers using the χ2 test. Taking together, the results for this and previous studies, it appears the MRE was fairly constant over the past 5000 yr.

Mesolithic hunter-gatherer settlements generally leave ephemeral archaeological traces and are notoriously difficult to detect. Nowhere is this more so than on the northern coast of Spain, despite a long tradition of Mesolithic research. In this project, evidence of Mesolithic activity together with the geomorphological and topographical suitability of particular locations were used to select areas for large-scale geophysical survey. The results demonstrate the potential of the new methodology: magnetometry survey at El Alloru revealed the very first Asturian open-air settlement site to be discovered.

The prehistoric shell middens of Atlantic Europe consist of marine molluscs, but the eastern Baltic did not have exploitable marine species. Here the sole recorded shell midden, at Riņņukalns in Latvia, is on an inland lake and is formed of massive dumps of freshwater shells. Recent excavations indicate that they are the product of a small number of seasonal events during the later fourth millennium BC. The thickness of the shell deposits suggests that this was a special multi-purpose residential site visited for seasonal aggregations by pottery-using hunter-gatherer communities on the northern margin of Neolithic Europe.

Shells of the helicid Cepaea nemoralis were studied using taphonomic, isotopic and morphometric measurements to estimate late glacial–Holocene (~ 12.1–6.3 cal ka BP) environmental conditions in northern Spain. Higher taphonomic alteration among Holocene shells suggests lower sedimentation rates or higher shell-destruction rates than during glacial conditions. Shells preserved the aragonitic composition despite differing degree of skeleton damage. Shell δ13C values were − 10.3 ± 1.1‰, − 8.2 ± 2.3‰, and − 7.3 ± 1.6‰ for modern, Holocene and late-glacial individuals, respectively. Higher δ13C values during the late-glacial and some Holocene periods imply higher water stress of C3 plants and/or higher limestone contribution than today. Intrashell δ13C values were higher during juvenile stages suggesting higher limestone ingestion to promote shell growth. Shell δ18O values were − 1.1 ± 0.7‰, − 0.9 ± 0.8‰ and − 0.1 ± 0.7‰ for modern, Holocene and late-glacial specimens, respectively. A snail flux-balance model suggests that during ~ 12.1 − 10.9 cal ka BP conditions were drier and became wetter at ~ 8.4 − 6.3 cal ka BP and today. Intrashell δ18O profiles reveal that glacial individuals experienced more extreme seasonality than interglacial shells, despite possible larger hibernation periods. Shell size correlated positively with δ18O values, suggesting that growth rates and ultimate adult size of C. nemoralis may respond to climate fluctuation in northern Spain.

According to current thinking, the peopling of South America involved a coastal as well as an inland exploitation. Here the authors describe a camp that may denote a transition between the two. As indicated by bifacial tools, the investigation shows that people began to move inland and hunt mammals around 8500 cal BP, perhaps in association with a change in the climate.