Using foraminifera to distinguish between natural and cultural shell deposits in coastal eastern Australia

Foraminifera are single cell protozoa that are ubiquitous in marine environments. Although the hard casings, or tests, of foraminifera are routinely studied in the earth sciences, they have been little studied by archaeologists, despite their potential to contribute to understandings of coastal site formation processes and palaeoenvironments. In this study techniques and methods of foraminiferal analysis are developed and applied to the problem of distinguishing between natural and cultural marine shell deposits, using the Mort Creek Site Complex, central Queensland, Australia, as a case study. Results allow separation of natural and cultural deposits based on foraminiferal density. Natural deposits were found to have >1000 foraminifera per 100 g of sediment, while cultural deposits exhibited <50 foraminifera per 100 g of sediment. Results allow us to better understand site formation processes at the Mort Creek Site Complex and highlight the potential of foraminiferal analyses in the interpretation of terrestrial marine deposits.     

Oxygen isotopic composition of limpet shells from the Beagle Channel: implications for seasonal studies in shell middens of Tierra del Fuego

Shell middens distributed along the coastal areas of the Beagle Channel (Tierra del Fuego) testify the primary role of marine resources in the successful social dynamic of hunter–gatherer–fisher societies (HGF) in extreme high latitude environmental conditions. Intertidal and subtidal limpet species are frequently identified taxa of these archaeological deposits. We investigated whether shell δ¹⁸O of the limpet species Nacella deaurata is a valuable record of local sea surface temperature (SST) and ambient water δ¹⁸O (δ¹⁸Ow) fluctuations, and in turn can be used to estimate the season of its exploitation by Holocene HGF. Sequential shell δ¹⁸O of modern species track seasonal changes of SST and δ¹⁸Ow. The comparison of shell δ¹⁸O profiles of N. deaurata and Nacella magellanica (a coexisting species) suggests the occurrence of distinct growth rate and physiological adaptations between species. Shell δ¹⁸O of zooarchaeological specimens of N. deaurata from Lanashuaia II suggests that animals were exploited predominantly in winter and that experienced similar environmental conditions of present day at ∼1320 years BP. Results also indicate that N. deaurata is a valuable candidate for studying past seasonal changes in SST and δ¹⁸Ow in this southernmost part of South America.     

Some chronological implications of a fossil molluscan assemblage from a neolithic site at Brook,Kent, England

The later post-glacial history of a valley in the chalk escarpment near Brook, Kent, is described, based on molluscan stratigraphy, archaeological evidence and radio-carbon dating. Differences in size and colour banding, respectively, of fossil and living representatives of two species of land snails, Pomatias elegans (Müller) and Cepaea nemoralis (L.), are correlated with climatic change during the post-glacial period. The problems of the use of fossil shells of these species as samples for radiocarbon dating are discussed.     

Prehistoric shell beads on the Georgia coast

ABSTRACT

The prehistoric peoples living along the Georgia coast fabricated and used shell beads for millennia. Out of a number of mollusk species inhabiting the region, only a few were selected for the fabrication of beads. The knobbed whelk (Busycon carica) was the most common species used, and it represents the most common whelk found in Atlantic coastal waters. The lightning whelk (Busycon sinistrum), the second most common whelk in the region, was occasionally used in the production of beads. Small numbers of beads were made from marginella and olive shells and, rarely, from bivalve species. Small beads were manufactured from the body whorl of whelks, while larger beads were fabricated from whelk collumella. Shell beads appear in small quantities in Late Archaic period contexts, and then almost disappear during the Woodland period. Beads reappear in quantities at about AD 800 in the Early Mississippian period. More shell beads have been recovered from Mississippian period archaeological contexts along the northern Georgia coast than along the southern coast, reflective of cultural differences between these two geographic areas in the post-Woodland period era.