One defining characteristic of Homo sapiens is the production and use of personal ornamentation. Evidence from Africa and western Eurasia has dominated discussion, but a growing number of finds directs attention towards Island Southeast Asia. In this article, the authors report on an assemblage of Nautilus shell beads from the Indonesian cave site of Makpan, Alor Island. The highly standardised forms, mostly with two perforations, and evidence of use wear, indicate that these beads were utilised as appliqués. Dating to the terminal Pleistocene, these beads appear to form part of a wider tradition also attested on Timor and Kisar, suggesting an early inter-island network across southern Wallacea.

In the US Midwest, the working of marine shell procured through vast trade networks has typically been associated with elite prestige economies and craft specialization at major Mississippian centers. Outside of these contexts, marine shell goods are often assumed to have been brought into communities as completed goods. A recent finding suggests that local, small-scale marine shell working occurred at an early seventeenth-century village in northern Illinois, Middle Grant Creek (11Wi2739). This finding represents the first probable evidence of marine shell working in the Midwest outside of large, Mississippian contexts. Consequently, this practice may be much more geographically and temporally expansive than previously thought. This evidence encourages a rethinking of marine shell finds whenever they are assumed to be imported as finished goods.

Biogeochemical analyses of eastern oysters (Crassostrea virginica) are frequently included in environmental monitoring and paleoecological studies because their shells and soft tissues record environmental and dietary signals. Carbon isotopes in the mineral phase of the shell are derived from ambient bicarbonate and dissolved inorganic carbon (DIC), while organic carbon present in soft tissue is of dietary origin. Mineral-bound organic matter within the carbonate shell matrix (“conchiolin”) is studied less frequently. The purpose of this study was to compare carbon isotope composition (δ13C and Δ14C) of conchiolin to those of shell carbonates and soft tissues in eastern oysters and assess the extent to which conchiolin can provide insight into paleoecological records. Eleven oyster specimens were live-collected from Apalachicola Bay, USA, as well as a set of environmental samples (water, sediment, and terrestrial plants). Overall, the δ13C values in all studied oyster tissue types record environmental signals related to carbon sources, with conchiolin being enriched in 13C by an average of 2.3‰ relative to bulk soft tissues. Δ14C values in oyster shell carbonates generally reflect the marine versus riverine source of DIC, while conchiolin Δ14C values are impacted by variable relative contributions of young and old organic matter. Environmental samples indicate a significantly large difference in Δ14C among sources, from –127‰ in particulate organic matter to approximately +15‰ in DIC. Conchiolin is significantly depleted in 14C relative to other tissue types, by as much as 56.6‰, posing a major obstacle to the use of conchiolin as an alternative material for radiocarbon dating.

Archaeological investigations of the age and origins of marine shell beads are important for understanding the emergence and maintenance of long-distance trade networks in prehistory. In this paper we expand upon and re-examine the incremental carbon (14C and δ13C) and oxygen (δ18O) isotope data from two Olivella biplicata shell beads from the LSP-1 Rockshelter, Oregon, USA, to address two common problems in dating marine shell trade goods: (1) the source region is large, adding to uncertainty regarding the appropriate specification of ΔR; and (2) the 14C activity within individual specimens is variable. Although this combination of factors severely limits the dating precision that is possible, we recommend a sampling and calibration approach that accounts for these added sources of uncertainty and minimizes the loss of precision. We recommend (1) sequential sampling in order to quantify the range of variability in 14C within shells; (2) a Bayesian calibration procedure that models the 14C dates as an ontogenetic sequence, in this case constrained by stable isotope sclerochronology; and (3) specifying ΔR in a manner that accounts for the full range of possible reservoir offsets in the source region.

Models of late-glacial environmental change in coastal areas are commonly based on radiocarbon ages on marine shell and basal lake sediments, both of which may be compromised by reservoir effects. The magnitude of the oceanic reservoir age in the inland waters of the Georgia Basin and Puget Lowland of northwestern North America is inferred from radiocarbon ages on shell-wood pairs in Saanich Inlet and previously published estimates. The weighted mean oceanic reservoir correction in the early and mid Holocene is −720±90 yr, slightly smaller than, but not significantly different from, the modern value. The correction in late-glacial time is −950±50 yr. Valley-head sites yield higher reservoir values (−1200±130 yr) immediately after deglaciation. The magnitude of the gyttja reservoir effect is inferred from pairs of bulk gyttja and plant macrofossil ages from four lakes in the region. Incorporation of old carbon into basal gyttja yields ages from bulk samples that are initially about 600 yr too old. The reservoir age declines to less than 100 yr after the first millennium of lake development. When these corrections are accounted for, dates of deglaciation and late-glacial sea-level change in the study area are pushed forward in time by more than 500 yr.

Strombus alatus and Busycon sinistrum are large marine gastropods that are frequently recovered from archaeological contexts in southeastern North America. We previously proposed a reservoir age offset (ΔR) for B. sinistrum from the northern Gulf of Mexico region based on known-age pre-bomb 20th-century specimens. We also reported significant variability in radiocarbon both among and within S. alatus specimens, which precluded a reliable estimation of ΔR for this taxon. In this paper, we present a complementary data set from archaeological contexts to re-evaluate marine reservoir effects in the northern Gulf Coast region at multiple spatial and temporal scales. The new data set consists of a total of 13 14C age determinations from well-associated marine (B. sinistrum and S. alatus) and terrestrial (Odocoileus virginianus) samples from a closed context at the Bayou St. John (1BA21) archaeological site. We suggest a slightly updated ∆R value of –2±53 14C yr for late Holocene-age B. sinistrum from the northern Gulf Coast region. S. alatus, and possibly other species of strombid conchs, are poor candidates for 14C dating due to the highly variable 14C content observed within and among specimens. Though subregional variability in inputs of 14C-depleted waters is likely, life-history factors related to ontogenetic niche and/or habitat shifts appear to be a major influence in shell 14C for S. alatus.