Marine Radiocarbon Reservoir Effect in Late Pleistocene and Early Holocene Coastal Waters off Northern Iberia

Radiocarbon dating of closely associated marine mollusk shells and terrestrial material (mammal bones or charred wood) collected from archaeological contexts in northern Atlantic Iberian coastal areas is used to quantify the marine 14C reservoir effect (ΔR) for the coastal waters off the Cantabrian coast (northern Iberia). For the first time, ΔR values were reliably determined for these coastal waters, and also for the first time a ΔR was calculated for the Late Pleistocene in Atlantic Iberia. Pairs of coeval samples of different carbon reservoirs selected from Upper Paleolithic (Late Pleistocene) and Mesolithic (Early Holocene) contexts yielded ΔR weighted mean values of −117±70 14C yr and −105±21 14C yr, respectively. These values show oceanographic conditions characterized by a reduced offset between atmospheric and surface water 14C contents, suggesting a nonexistent or a very weak upwelling and some stratification of the water column. Similar oceanographic conditions have been recorded in other areas of Atlantic Iberia during the Holocene, such as off Andalusian and northwestern Galician coasts. Results not only provide useful information on environmental conditions but also a framework to obtain more precise and reliable absolute chronologies for the Late Pleistocene and Early Holocene in northern Iberia

Mollusc exploitation in cantabrian prehistory : research history and theoretical approaches

En este artículo se realiza una revisión crítica de la Historia de las investigaciones sobre la explotación del litoral, y especialmente sobre la explotación de moluscos, durante el Paleolítico superior, el Mesolítico y el Neolítico en la región cantábrica, así como de los marcos teóricos que han influenciado dicha investigación. Desde finales del siglo XIX, el estudio de concheros prehistóricos se llevó a cabo bajo el marco del paradigma histórico-cultural y la influencia de los prehistoriadores franceses. A partir de los años 60 y 70 del siglo XX, la llegada de investigadores norteamericanos permitió la introducción del procesualismo en la región, lo que produjo un cambio significativo en la forma de plantear las investigaciones. En los últimos 30 años los datos del registro arqueológico han aumentado considerablemente en cantidad y calidad, mientras los enfoques teóricos se han mantenido estables, si bien la introducción del materialismo histórico ha supuesto la apertura de nuevas perspectivas de análisis e interpretación, aunque han sido escasamente desarrolladas hasta el momento

Ornaments from the Magdalenian burial area in El Mirón Cave (Cantabria, northern Spain). Were they grave goods?

International audienceEl Mirón Cave, located in northern Atlantic Iberia, has produced important evidence of human occupation during the Lower Magdalenian (19-17.5 cal kya). Among the finds dating to this period is that of a disturbed primary burial of an adult woman. The excavation of the small area around the burial yielded a considerable number of ornamental items (mainly shell beads), but the actual association of any of them with the interment is problematic. The results of our study of the perforated marine shells and mammal teeth suggest that the ornamental objects were not grave goods, but rather were simply artifacts present in the occupation layers in this part of the cave. The materials used to make ornaments were gathered by collecting shells along the Late Glacial shore and by hunting ungulates. The perforation techniques used were similar to those found at contemporary sites in the Franco-Cantabrian region and the appearance of various elements from the manufacturing operatory chain indicates that some of the ornaments were made at the site. It was also possible to determine that some of the shells were used—probably suspended or attached to other objects. From a functional standpoint, the ornaments probably played not only an aesthetic role, but also a symbolic one, facilitating communication and exchanges among human groups

Collection and consumption of echinoderms and crustaceans at the Mesolithic shell midden site of El Mazo (northern Iberia) : Opportunistic behaviour or social strategy?

Recent studies in Atlantic Europe on crab remains, goose barnacles and sea urchins have revealed that these species can be of great help in determining patterns of shellfish collection and providing new information on subsistence strategies of hunter-fisher-gatherers. Current excavations at the Mesolithic shell midden site of El Mazo cave (Asturias, northern Iberia) have produced a sizeable amount of crustacean and echinoderm remains from a long stratigraphic sequence that covers an important part of the Mesolithic chronological range, providing the opportunity to investigate long-term exploitation patterns. Results show that echinoderms (sea urchins) and crustaceans (goose barnacles and crabs) were present throughout all of the stratigraphic units (from 8.9 to 7.6 cal kyr), suggesting that they were a persistently exploited food source. However, these resources were not intensively exploited, save perhaps sea urchins at the base of the sequence. From a quantitative perspective, these resources have been traditionally interpreted as minor resources exploited opportunistically to help group survival. However, given the pattern of continuous exploitation exhibited by these resources in northern Iberia and other areas of Atlantic Europe, we suggest that they can be interpreted from a qualitative perspective as stable resources with a significant social valu

The shell midden of Pico Ramos and the exploitation of molluscs in the Cantabrian region (northern Spain)

ABSTRACT: Human groups exploited molluscs during the Mesolithic-Neolithic transition (MNT) at Pico Ramos. Results show that the most exploited species were limpets and topshells collected in rocky open shores, while other species were collected in estuaries. Therefore, different environments were exploited by human groups. This pattern is related to the location of the cave in the mouth of the estuary. The exploitation pattern suggests that collection was carried out in several short visits to the cave. The characteristics of the accumulation also fit the pattern of intensification identified in the region, which show that molluscs were important for human groups during the Mesolithic and the early Neolithic. However, it is difficult to establish if Pico Ramos was used by hunter-gatherers resisting the introduction of agriculture and domestication, or if on the contrary it was a specialized site used by food producers for hunting-fishing-gathering activities.This paper was written as part of the project HAR2010-22115-C02-01, funded by the Spanish Minister of Science and Innovation

Automated measurement of magnesium/calcium ratios in gastropod shells using laser-induced breakdown spectroscopy for paleoclimatic applications

The chemical composition of mollusk shells offers information about environmental conditions present during the lifespan of the organism. Shells found in geological deposits and in many archeological sites can help to reconstruct past climatic conditions. For example, a correlation has been found between seawater temperature and the amount of some substituent elements (e.g., magnesium, strontium) in the biogenerated calcium carbonate matrix of the shell, although it is very species-specific. Here we propose the use laser-induced breakdown spectroscopy (LIBS) to estimate Mg/Ca ratios in modern specimens of the common limpet Patella vulgata. An automated setup was used to obtain a sequence of Mg/Ca ratios across a sampling path that could be compared with the seawater temperatures recorded during the organism's lifespan. Results using four shells collected in different months of the year showed a direct relationship between the Mg/Ca ratios and the seawater temperature, although the sequences also revealed small-scale (short-term) variability and an irregular growth rate. Nevertheless, it was possible to infer the season of capture and the minimum and maximum seawater temperatures from the LIBS sequences. This fact, along with the reduction in sampling and measurement time compared with other spectrometric techniques (such as inductively coupled plasma mass spectrometry [ICP-MS]), makes LIBS useful in paleoclimatic studies.The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article. This research was part of the projects TEC2013-47264-C2-1-R and HAR2013-46802-P, both funded by the Spanish Ministry of Economy and Competitiveness. Asier García-Escázaga was funded by the University of Cantabria through a predoctoral grant and Igor Gutierrez-Zugasti was supported by the Juan de la Cierva programme (JCI-2012-12094) funded by the Spanish Ministry of Economy and Competitiveness

La influencia de la temperatura en la datación de conchas por racemización de aminoácidos de los yacimientos de El Perro y La Fragua (Santoña, Cantabria)

Los yacimientos de El Perro y La Fragua se sitúan en el Monte Buciero (Santoña), separados únicamente por apenas 600 metros, en una zona que presenta un microclima particular que provoca el desarrollo de una vegetación con variedad de especies mediterráneas relictas y otras de carácter más atlántico. Ambos presentan niveles del Magdaleniense, Aziliense y Mesolítico que han sido datados empleando el método del carbono-14. En todos los niveles se encuentran abundantes restos de moluscos, incluyendo representantes del género Patella, que se analizaron mediante el método de racemización de aminoácidos. Las edades obtenidas con este método son superiores a las de radiocarbono y a la atribución cultural de los materiales

Shells and humans: molluscs and other coastal resources from the earliest human occupations at the Mesolithic shell midden of El Mazo (Asturias, Northern Spain)

Human populations exploited coastal areas with intensity during the Mesolithic in Atlantic Europe, resulting in the accumulation of large shell middens. Northern Spain is one of the most prolific regions, and especially the so-called Asturian area. Large accumulations of shellfish led some scholars to propose the existence of intensification in the exploitation of coastal resources in the region during the Mesolithic. In this paper, shell remains (molluscs, crustaceans and echinoderms) from stratigraphic units 114 and 115 (dated to the early Mesolithic c. 9 kys cal BP) at El Mazo cave (Asturias, northern Spain) were studied in order to establish resource exploitation patterns and environmental conditions. Species representation showed that limpets, top shells and sea urchins were preferentially exploited. One-millimetre mesh screens were crucial in establishing an accurate minimum number of individuals for sea urchins and to determine their importance in exploitation patterns. Environmental conditions deduced from shell assemblages indicated that temperate conditions prevailed at the time of the occupation and the morphology of the coastline was similar to today (rocky exposed shores). Information recovered relating to species representation, collection areas and shell biometry reflected some evidence of intensification (reduced shell size, collection in lower areas of exposed shores, no size selection in some units and species) in the exploitation of coastal resources through time. However, the results suggested the existence of changes in collection strategies and resource management, and periods of intense shell collection may have alternated with times of shell stock recovery throughout the Mesolithic.This research was performed as part of the project “The human response to the global climatic change in a littoral zone: the case of the transition to the Holocene in the Cantabrian coast (10,000–5000 cal BC) (HAR2010-22115-C02-01)” funded by the Spanish Ministry of Economy and Competitiveness. AGE was funded by the University of Cantabria through a predoctoral grant and IGZ was funded by the Spanish Ministry of Economy and Competitiveness through a Juan de la Cierva grant. We also would like to thank the University of Cantabria and the IIIPC for providing support, David Cuenca-Solana, Alejandro García Moreno and Lucia Agudo Pérez for their help. We also thank Jennifer Jones for correcting the English. Comments from two anonymous reviewers helped to improve the paper

La explotación de moluscos en la prehistoria cantábrica: historia de las investigaciones y enfoques teóricos

En este artículo se realiza una revisión crítica de la Historia de las investigaciones sobre la explotación del litoral, y especialmente sobre la explotación de moluscos, durante el Paleolítico superior, el Mesolítico y el Neolítico en la región cantábrica, así como de los marcos teóricos que han influenciado dicha investigación. Desde finales del siglo XIX, el estudio de concheros prehistóricos se llevó a cabo bajo el marco del paradigma histórico-cultural y lainfluencia de los prehistoriadores franceses. A partir de los años 60 y 70 del siglo XX, la llegada de investigadores norteamericanos permitió la introducción del procesualismo en la región, lo que produjo un cambio significativo en la forma de plantear las investigaciones. En los últimos 30 años los datos del registro arqueológico han aumentado considerablemente en cantidad y calidad, mientras los enfoques teóricos se han mantenido estables, si bien la introducción del materialismo histórico ha supuesto la apertura de nuevas perspectivas de análisis e interpretación, aunque han sido escasamente desarrolladas hasta el momento

Middle Paleolithic Mode 3 lithic technology in the rock shelter Benzú (North Africa) and its inmediate enviromental relationships

Artículo sobre la tecnología de Modo 3 en Benzú y su relación con el ecosistema adyacente