Amino acid racemization dating of marine shells: a mound of possibilities

Shell middens are one of the most important and widespread indicators for human exploitation of marine resources and occupation of coastal environments. Establishing an accurate and reliable chronology for these deposits has fundamental implications for understanding the patterns of human evolution and dispersal. This paper explores the potential application of a new methodology of amino acid racemization(AAR) dating of shell middens and describes a simple protocol to test the suitability of different molluscanspecies. This protocol provides a preliminary test for the presence of an intracrystalline fraction of proteins(by bleaching experiments and subsequent heating at high temperature), checking the closed system behaviour of this fraction during diagenesis. Only species which pass both tests can be considered suitable for further studies to obtain reliable age information. This amino acid geochronological technique is also applied to midden deposits at two latitudinal extremes: Northern Scotland and the Southern Red Sea.Results obtained in this study indicate that the application of this new method of AAR dating of shells has the potential to aid the geochronological investigation of shell mounds in different areas of the world

Early and Middle Holocene Hunter-Gatherer Occupations in Western Amazonia: The Hidden Shell Middens

We report on previously unknown early archaeological sites in the Bolivian lowlands, demonstrating for the first time early and middle Holocene human presence in western Amazonia. Multidisciplinary research in forest islands situated in seasonally-inundated savannahs has revealed stratified shell middens produced by human foragers as early as 10,000 years ago, making them the oldest archaeological sites in the region. The absence of stone resources and partial burial by recent alluvial sediments has meant that these kinds of deposits have, until now, remained unidentified. We conducted core sampling, archaeological excavations and an interdisciplinary study of the stratigraphy and recovered materials from three shell midden mounds. Based on multiple lines of evidence, including radiocarbon dating, sedimentary proxies (elements, steroids and black carbon), micromorphology and faunal analysis, we demonstrate the anthropogenic origin and antiquity of these sites. In a tropical and geomorphologically active landscape often considered challenging both for early human occupation and for the preservation of hunter-gatherer sites, the newly discovered shell middens provide evidence for early to middle Holocene occupation and illustrate the potential for identifying and interpreting early open-air archaeological sites in western Amazonia. The existence of early hunter-gatherer sites in the Bolivian lowlands sheds new light on the region's past and offers a new context within which the late Holocene "Earthmovers" of the Llanos de Moxos could have emerged. © 2013 Lombardo et al

Análisis tafonómicos de conjuntos arqueomalacológicos: concheros en la costa norte de Santa Cruz (Patagonia, Argentina)

En este trabajo se presenta una propuesta metodológica para el estudio de conjuntos arqueomalacológicos de concheros y su aplicación en el análisis de restos recuperados a partir de excavaciones sistemáticas en sitios ubicados al sur de la ría Deseado, en la costa norte de Santa Cruz, Patagonia argentina. Esta metodología se focaliza en el estudio de diferentes variables tafonómicas que afectan el registro arqueomalacológico para avanzar en la interpretación de los agentes y procesos involucrados en la formación de las estructuras de concheros y sobre las actividades humanas desarrolladas en los sitios. Además estos análisis son significativos para realizar interpretaciones paleoambientales, paleoecológicas, así como para evaluar la integridad de los conjuntos, interpretar las características estructurales y la variabilidad de los sitios.This paper proposes a method of studying archaeomalacological assemblages from shell middens, and describes an application of this method in the analysis of remains recovered from systematic excavations at sites located south of the Ría Deseado estuary (northern coast of Santa Cruz Province, Argentina). This methodology aims to isolate taphonomic variables affecting archaeomalacological records to aid identification of the agents and processes involved in shell midden formation and to improve interpretations of the human activities performed at the sites. These analyses are also relevant to paleoenvironmental and paleoecological reconstructions, and to interpretations of site variability through assessments of assemblage integrity and structure.Fil: Hammond, Heidi. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Arqueología; Argentin

A marine reservoir effect ΔR value for Kitandach, in Prince Rupert Harbour, British Columbia, Canada

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 km. These sites span the last 9500 yr and in some cases are immense, exceeding 20,000 m 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 speci fic 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

Mussels with Meat: Bivalve Tissue-Shell Radiocarbon Age Differences and Archaeological Implications

Local reservoir ages are often estimated from the difference between the radiocarbon ages of aquatic material and associated terrestrial samples for which no reservoir effect is expected. Frequently, the selected aquatic material consists of bivalve shells that are typically well preserved in the archaeological record. For instance, large shell middens attest to the importance of mussel consumption at both coastal and inland sites. However, different physiological mechanisms associated with tissue and shell growth may result in differences in reservoir effects between the surviving component (shell) and the component relevant to dietary reservoir effects in consumers (tissue). The current study examines bivalve tissue-shell age differences both from freshwater and marine contexts close to archaeological sites where human consumption of mollusks has been attested. Results exhibited significant 14C age differences between bivalve tissue and shell in a freshwater context. In a marine context, no significant bivalve tissue-shell age differences were observed. The results also showed that riverine and lacustrine shells show large and variable freshwater reservoir effects. The results have important implications for establishing local reservoir effects especially in a freshwater environment. For good a priori knowledge of expected 14C differences in organic and inorganic water, carbon is thus necessary. Furthermore, the high variability in freshwater shell 14C ages implies the need for representative sampling from the archaeological record

Correction to: ‘Violence in the prehistoric period of Japan: the spatio-temporal pattern of skeletal evidence for violence in the Jomon period’

Whether man is predisposed to lethal violence, ranging from homicide to warfare, and how that may have impacted human evolution, are among the most controversial topics of debate on human evolution. Although recent studies on the evolution of warfare have been based on various archaeological and ethnographic data, they have reported mixed results: it is unclear whether or notwarfare among prehistoric hunter–gathererswas common enough to be a component of human nature and a selective pressure for the evolution of human behaviour. This paper reports the mortality attributable to violence, and the spatio-temporal pattern of violence thus shown among ancient hunter–gatherers using skeletal evidence in prehistoric Japan (the Jomon period: 13 000 cal BC–800 cal BC). Our results suggest that the mortality due to violence was low and spatio-temporally highly restricted in the Jomon period, which implies that violence including warfare in prehistoric Japan was not common

Vertebrates from Cabeço dos Morros: a Mesolithic shell midden near Salvaterra de Magos, in the lower Tagus valley, Portugal

This article discusses the vertebrate remains recovered from the Mesolithic shell midden of Cabeço dos Morros on the Magos River in the lower Tagus Valley, Portugal. It is the first publication on the fauna of the (Mesolithic) Tagus Shell Midden Complex of the Magos River. The Tagus shell middens are considered key sites for investigating the last hunter-gatherers of the Iberian Peninsula because they include some of the largest Mesolithic settlements in the region and altogether represent a significant period of occupation. The Mesolithic is an interesting and complex period in Iberian prehistory because itmbridges the period in which Upper Palaeolithic hunter-gatherers became Neolithic farmer and also because it extends over critical periods of environmental, demographic and social changes about which little is known