Optical dating of alluvial deposits at the orogenic front of the andean precordillera (Mendoza,Argentina)

Well constrained numerical ages of alluvial fan sediments are key to understanding the chronology of alluvial episodes and tectonic activity at the front of the Andean Precordillera. We tested the application of radiocarbon and optically stimulated luminescence (OSL) dating in the distal part of an alluvial fan five kilometers north of Mendoza. For OSL dating a large number of aliquots (n > 70) — each composed of ∼50 quartz grains — were measured in order to obtain reliable burial ages despite scattered dose distributions. Owing to a feldspar contamination in all samples, an infrared stimulation was inserted before each OSL measurement, which reduced the feldspar OSL signal successfully. By using the minimum age model we obtained stratigraphically consistent burial ages of alluvial deposits in a depth profile. The uppermost ∼1 m of sediment is composed of debris flow deposits buried 770±76 years ago. Three plant remnants used for radiocarbon dating from the same layer, however, yielded ages younger than 350 years, which are interpreted to underestimate the depositional age. Underneath the debris flow, a major unconformity cuts a series of distal alluvial fan sediments with interstratified floodplain deposits, which are composed of sandy and calciterich silt layers, respectively. Three samples from this unit which were distributed over one meter of sediment thickness yielded statistically concordant OSL ages of 12.3±1.2 ka, 12.3±1.2 ka, and 11.7±1.1 ka. The deposition of these sediments during the latest Pleistocene coincides with a phase of cool and humid climate, which occurred before the alluvial fan propagated farther into the foreland. The overlying debris flow sediments are associated with alluvial fan incision during the arid Late Holocene.     

Neolithic occupation and mid-Holocene soil formation at Encosta de Sant'Ana (Lisbon,Portugal): a geoarchaeological approach

Excavations at the archaeological site of Encosta de Sant'Ana (Lisbon, Portugal) uncovered a mid-Holocene buried alluvial soil associated with early Neolithic occupation layers. Routine laboratory analyses and micromorphological observations were undertaken on the soil material. Humic acids from its Ab horizon, as well as Neolithic ecofacts, were radiocarbon dated. The dates obtained indicate that soil was formed between c. 8.0 and 6.0 cal ka BP and that the pedological evidence fits the record of the North Atlantic Holocene IRD events (“Bond events”) and the so-called “Holocene climate optimum”. The geoarchaeological record reveals that Neolithic inhabitants settled upon a stable surface, still affected by soil formation that was suddenly interrupted by slope wasting, probably in correspondence to Bond event 4, at c. 6.0 cal ka BP.     

Radiocarbon dating of marine shell samples. The marine radiocarbon reservoir effect of coastal waters off Atlantic Iberia during Late Neolithic and Chalcolithic Periods

Radiocarbon dates on marine shells have not been used as extensively as charcoal or bone dates for the setting up of absolute chronologies because interpreting these dates is complicated by the marine radiocarbon reservoir effect. Nevertheless marine shellfish were used widely at least during the Holocene and their shells are abundant and usually well preserved in archaeological deposits located near shorelines. Consequently prior research concerning the oceanographic conditions and the marine radiocarbon reservoir effect of a particular coastal area is needed in order to set up reliable chronologies for that region. Values of regional marine radiocarbon reservoir effect – ΔR – of coastal waters off Atlantic Iberia, some of its variability along the Holocene and its correlation with the upwelling phenomenon were determined during previous research. More data related to the ΔR values for western Portuguese coastal waters during the Late Neolithic and the Chalcolithic, a time interval badly sampled in previous research, were recently obtained. These values can be compared with ΔR values already determined for the Gulf of Cadiz. Besides the importance of these values for a better knowledge of the palaeoceanography and palaeoclimatology of Atlantic Iberia, from now on archaeologists can set up reliable chronologies for Late Neolithic and Chalcolithic contexts using marine shell samples of that origin for radiocarbon dating.     

HOLOCENE ACCUMULATION OF COLLUVIAL AND ALLUVIAL SEDIMENTS IN THE WEIßE ELSTER RIVER VALLEY IN SAXONY,GERMANY*

Geoarchaeological investigations at two archaeological excavation sites lead to new results with respect to the Holocene landscape development of an archaeologically important loess landscape of Central Europe. Colluvial and alluvial sediments were sampled during archaeological excavations on the valley edge of the Weiße Elster and dated by means of ¹⁴C, TL and dendrochronology, and on the basis of archaeological finds. Thus, for the first time, the development of a valley edge of a river in the Leipzig area, which has been continuously settled for 7300 years, can be reconstructed. The first soil erosion on the valley edge is established towards the end of the Atlantic period. During the High Middle Ages, a colluvial sediment developed. Its deposition time can be limited to between ad 1000 and 1100. The flood loam near Großstorkwitz, which can be stratified by means of the soil and colluvial deposits, originated in the late Sub‐Boreal and early Sub‐Atlantic, as well as after ad 1100. During the first millennium ad, a soil developed in the older flood loam, which indicates a phase of reduced flood loam sedimentation.     

Palaeodiet of Mesolithic and Neolithic populations of Meuse Basin (Belgium): evidence from stable isotopes

The human diet was investigated using the carbon and nitrogen isotopic signatures of 93 Mesolithic and Neolithic specimens (∼10,000–2000 BC) from the Meuse Basin (Belgium). During the Ancient Mesolithic period (∼9300–8000 BC), the environment was generally open and the main dietary protein was provided by hunted terrestrial mammals, with the possible addition of freshwater resources. Human remains are not available in the Meuse Basin from around 8000 BC to 4300 BC, thus preventing the study of the Mesolithic-Neolithic dietary transition in this region. Throughout the Middle Neolithic (∼4300–3000 BC), hunting was more difficult and less productive due to a densely forested environment. The contribution of freshwater resources to the diet increased, with the remaining proteins provided by terrestrial wild and/or domestic mammals, indicating that non-agricultural resources were not eliminated in this region during the Middle Neolithic period. The contribution of freshwater resources seems negligible in the Middle/Late and Late Neolithic periods (∼3300–1700 BC), with isotopic results revealing a diet composed of agricultural products. The δ¹⁵N values of infants are compatible with a weaning age at around 2 years. This study documents the dietary changes that occurred in Belgium during the first part of the Holocene, and reveals the subtle dietary distinction between wild and domestic terrestrial resources and freshwater resources.     

MOLLUSC SHELL SIZES IN ARCHAEOLOGICAL CONTEXTS IN NORTHERN SPAIN (13 200 TO 2600 CAL BC): NEW DATA FROM LA GARMA A AND LOS GITANOS (CANTABRIA)

Shellfish metrical data are a source of information about the exploitation of marine resources in the past. In this study, we propose a methodological approach based on the size structures of different rocky intertidal gastropod species. Three limpet species (Patella vulgata, Patella intermedia and Patella ulyssiponensis) and the toothed topshell Osilinus lineatus are studied from two sites in Cantabrian Spain: La Garma A and Los Gitanos caves over a period of 10 000 years, covering the Pleistocene–Holocene transition. Data are also supplied about a further sea snail species, the periwinkle Littorina littorea (Upper Magdalenian). A reduction in size can be seen, between the upper Magdalenian and the late Neolithic, in the case of the first four species. The explanation for this decline is probably related to the climate change that occurred in the transition between the Late Pleistocene and the Holocene, but it is possible that human impact might also have influenced shell sizes in the Mesolithic and Neolithic.     

OSL dating using quartz fine grains extracted from loess in Upper Palaeolithic sites of Nihewan Basin, northern China

Although radiocarbon (¹⁴C) dating, uranium-series dating, and optically stimulated luminescence (OSL) dating have been conducted for Upper Palaeolithic sites in the Nihewan Basin, northern China, there is room for constructing a detailed chronological framework. In this study, loess sediments collected from two Upper Palaeolithic sites, Youfang site and Hutouliang site, were dated using the single-aliquot regenerative-dose (SAR) OSL protocol. OSL measurements for palaeodoses estimation used fine-grained quartz samples extracted from loess. OSL dating results were obtained as 10–17 ka. These OSL ages were consistent with the related stratigraphy of Palaeolithic sites, archaeological evidence and independent ¹⁴C ages.     

Dating the Ramat Saharonim Late Neolithic desert cult site

The Ramat Saharonim site, located in the central Negev desert, Israel, consists of four shrines in a shallow valley and 30 tumuli, aligned on two cuesta cliffs on the valley's sides. Previous assessments based on site surveys suggested a general chronological span from Late Neolithic period (ca. 5000–5500 BC) through the Early Bronze Age (third millennium BC). Excavations in one shrine and three tumuli revealed a well-constructed double wall at the shrine and seven primary adult burials in the three tumuli. Quartz from sediment samples post-dating the construction of the burials and shrine was dated by optically stimulated luminescence (OSL) using the single aliquot regenerative dose (SAR) protocol, and charcoal and leather samples were dated by ¹⁴C. The OSL results for a burial in one tumulus are 7500 ± 700 to 6000 ± 600 years. In a second tumulus, OSL ages of 2000 ± 200–1800 ± 170 years and a ¹⁴C age on leather of 390–200 BC (2340–2150 cal BP) imply that this burial is Nabatean and that the site was used also in the Hellenistic period. Two ¹⁴C ages on charcoal from the shrine give an age between 5280 and 4710 BC (7230–6660 cal BP). OSL single aliquot ages for sediment from the shrine are highly scattered and far too old (60,000 to 12,000 years). The unlikely old ages are due to insufficient resetting of the OSL signal of some of the quartz grains when sand was blown onto the site. Indeed, single grain measurements for six samples of sediment postdating the shrine show a very large range of grain ages, but with a distinct young population in all samples. Ages calculated from these young populations average 5400 ± 800, in better consistence with the ¹⁴C dates and confirming our supposition that only some of the transported grains were reset at the time of deposition. The combined OSL and ¹⁴C dating shows that the shrines and tumuli are contemporaneous and attributes the complex to the Late Neolithic. This has clear ramifications for our understanding of the period and the rise of desert pastoral societies.     

Spatial–temporal distribution and geographic context of Neolithic cultural sites in the Hanjiang River Basin,Southern Shaanxi,China

Understanding how to live successfully within our environment is among the most pressing challenges facing contemporary society. This paper probes the problem based on comparative analysis and discusses the relationship between the spatial–temporal distribution of the Neolithic cultural sites and the geographic context in the Hanjiang River Basin in the south of Shaanxi Province, China. Archaeological studies have identified 175 Neolithic cultural sites in the study area, with a sequence of Laoguantai (¹⁴C age 8–7 ka BP), Yangshao (¹⁴C age 7–5 ka BP) and the late period of the Neolithic Age (¹⁴C age 5–4 ka BP). The total number of archaeological sites, the distribution area and the density all showed an early ascending and later descending trend, but the proportion of the number of archaeological sites in the study area to the corresponding value of the entire Shaanxi Province declined sharply. Spatially, these sites were concentrated on the terraces of the Hanjiang River and its main tributaries with an altitude of 400–800 m. Multiple data were integrated to clarify the critical effects of tectonic and geomorphologic conditions on the distribution of the Neolithic sites. Further comparisons revealed the correlation of Holocene climate change and environmental evolution with the Neolithic cultural succession in the study area that ameliorated conditions to generally promote the development of the primitive culture while degeneration coincided with the culture's transition or interruption. The discussion on the origin of the primitive culture and the temporal–spatial distribution corresponding to the regional culture differentiation sheds light on the complex and dynamic human–nature interaction system during the Neolithic Age, thus emphasising the wider field-based investigation and high-resolution reconstruction works of the palaeoclimate and palaeoenvironment in the future.     

The Environment and Subsistence of the Early Neolithic Settlement Area at Těšetice-Kyjovice,Czech Republic

This paper presents a reconstruction of environmental conditions and subsistence strategies in the Early Neolithic (6th Millenium BC) settlement area at Tě?etice-Kyjovice (Czech Republic). Our detailed reconstruction of the environment contributes to the unravelling of the genesis and spread of steppes and the formation of secondary anthropogenic forest-free areas in the Holocene in eastern-Central Europe. Mollusc shells, charcoals and plant macroremains were used as on-site evidence of a settlement environment. A relatively warm and dry anthropogenic forest-free area is reconstructed for the immediate vicinity of the Early Neolithic settlement. Communities of mixed deciduous forests are recorded in the surroundings of the settlement. Plant macroremains reflect the characteristic Neolithic range of cultivated plants (e.g. Triticum monococcum, Triticum dicoccon, Lens culinaris and Pisum sativum). Papaver somniferum seeds were also found, possibly constituting the oldest evidence of its presence and cultivation in the territory of the Czech Republic.     

Stability in the South Pacific surface marine C reservoir over the last 750 years. Evidence from American Samoa, the southern Cook Islands and the Marquesas

Although minor climatic and sea-level changes have been documented for the South Pacific during the late Holocene, our understanding of the consequent impact of these changes on the marine ¹⁴C reservoir, and therefore the ¹⁴C content of shellfish, is limited. Ultimately, this has implications for documenting the chronology of human movement and adaptation in this region. In this paper we compare marine reservoir (ΔR) data obtained from tightly controlled archaeological proveniences with known-age, pre-AD 1950 shells from the southern Cook Islands, American Samoa, and Marquesas Islands. Results indicate that there has been no significant change in the near-shore marine reservoir in these three locations over the last ca. 750 years. Furthermore, known-age, pre-AD 1950 shell samples provide more precise ΔR values for use in sample calibration than archaeological paired shell/charcoal samples. This is attributed in part to the limitations of assigning provenance and age to material from archaeological sites. On the basis of these results we conclude that the known-age, pre-AD 1950 shell derived ΔR values can be used to calibrate shell ¹⁴C results from deposits of late Holocene age.     

TRANSPORT AND SUBSISTENCE PATTERNS AT THE TRANSITION TO PASTORALISM,KOOBI FORA,KENYA

The Turkana Basin in Kenya has an extensive record of Holocene activities relating to mobility and economy of foraging and herding communities. Obsidian is only known from a few key localities in northern Kenya. As such, the use of obsidian as a toolstone material, commonly used during the mid‐Holocene, provides one way to trace exchange, interaction and population movements during the transition to pastoralism. We employ X‐ray fluorescence to characterize obsidian artefacts from four Pastoral Neolithic assemblages. Data reveal a highly mobile and diversified population that used watercraft to access and transport obsidian resources. Specifically, the use of the North Island obsidian source in Lake Turkana indicates that boat use was significant during this transitional period. The incorporation of watercraft transport and aquatic resources in our analyses of Pastoral Neolithic sites affords a greater understanding of subsistence, mobility and economy in this important period in East African prehistory.     

OPTICAL DATING OF GRANITIC STONE SURFACES*

A novel luminescence methodology for dating surfaces of granitoid rocks is presented, with encouraging results for archaeological stone structures. It is based on the zeroing of the latent signal of optically stimulated luminescence (OSL) in feldspar and quartz grains of the stone surface during exposure to daylight. When after bleaching the surface is shielded from light, the OSL signal builds up again, such that its intensity provides an age for the event of the last exposure to light. This event could be the construction or the destruction of stone structures or, for example, sedimentary deposition of granitic boulders, such as in fan deposits. The experimental approach utilizes a high spatial resolution detection technique (HR‐OSL) for OSL of minerals that are left in their original petrological context; that is, without any mineral separation. With this approach, steep gradients in microdosimetry at the surface and at grain boundaries become important and are discussed in detail. The new dating technique is successfully applied to a stone wall of the medieval castle of Lindenfels in southwestern Germany and the pre‐Columbian Nasca lines (geoglyphs) around Palpa in southern Peru.     

Holocene sediments of the Ustka Cliff (Northern Poland) in view of radiometric dating

The cliff in Ustka is an active one. The area is one of the most eroded sea shores of the Polish coast. The Ustka Cliff mainly consists of Holocene sandy deposits, but its basis is built of glacial till and clay. Field search allowed to recognize the structure and sedimentary conditions of Holocene deposits exposed in the cliff. A comparison of dating results obtained for fossil soils and peat as well as aeolian deposits, using ¹⁴C and TL methods, respectively, with available literature records is presented. The evaluation of results obtained allowed to define three main dune-forming phases for the first time for this part of the Polish coast. During the research studies new data on the processes and environmental conditions was gained and the development of structure of the area during the last 10 thousand years was reconstructed. The analysis of available data from other sections of the southern Baltic coast shows that results obtained are age similar to those determined for the ?eba Spit. The research is part of a project concerning the geomorphology of the Ustka Bay.     

Economics and environmental change during the Late Mesolithic and Neolithic periods — investigations in the valley of the Gieselau near Albersdorf,Schleswig-Holstein,Germany

Abstract

Interactions between people and the environment have resulted in constant changes in relief and soil conditions since the Neolithic. Soil transport and degradation had considerable effects on human land use. Extensive field investigations (excavations, auger sampling), measurements (e.g. texture, pH-value, C_org, N), datings (¹⁴C, pottery), together with extensive literature searches in different scientific disciplines (archaeology, palaeoecology, palaeoclimatology etc.), made it possible to reconstruct the Holocene landscape development in four study areas along the valley of the Gieselau near Albersdorf (Schleswig-Holstein, Germany). Stratigraphies were established in the study areas. This paper describes landscape developments around Albersdorf and in northern Central Europe during the Late Mesolithic and Neolithic. The compiled data for the landscape and land-use history serve as a basis for the design of the extensive Archaeological-Ecological Centre Albersdorf (AÖZA) — occupying a site of approximately 40 hectares — using reconstructed features from the Neolithic landscapes.     

MARINE RESOURCES IN THE MESOLITHIC AND NEOLITHIC AT THE GROTTA DELL’UZZO (SICILY): EVIDENCE FROM ISOTOPE ANALYSES OF MARINE SHELLS*

Oxygen isotopes in shell carbonate samples from the marine rocky‐shore intertidal gastropod Monodonta turbinata (Born) are investigated in both modern analogue specimens and in archaeological specimens from the Grotta dell’Uzzo (Sicily). Variations in shell edge values of δ¹⁸O in living specimens collected monthly over two years are closely correlated with monthly seawater temperatures measured at the time of collection, showing that the species can be used for palaeoseasonality studies. Analyses of shell edge δ¹⁸O values in archaeological specimens, from Mesolithic through to early Neolithic phases at the Grotta dell’Uzzo, enabled the inference of various seasons of collection of shellfish and how such seasonality varies between the different phases of occupation. Interesting similarities and differences exist between the seasons of marine shellfish exploitation and the seasons inferred from the vertebrate zooarchaeological assemblages. A major inference drawn from the analyses and discussion is that the exploitation of all marine resources (fish and shellfish) increased in the later Mesolithic and early Neolithic periods.     

Caesium-137 as an indicator of geomorphic processes in a drainage basin system

Caesium-137 from fallout from nuclear weapons tests is adsorbed on fine sediments and becomes an effective tracer. It is hypothesised that within a drainage basin, sites undergoing little or no erosion accumulate ¹³⁷ Cs in their upper layers; cultivated soils will have ¹³⁷ Cs uniformly distributed within the cultivated layer; eroded soils, cultivated or not, will have relatively less ^l37 Cs, depending on the severity of erosion. Accumulated sediments will have characteristic ¹³⁷ Cs profiles reflecting temporal fallout variations and sedimentation history. This hypothetical model is largely confirmed by results from Maluna Creek basin, where erosion and accumulation of sediments has taken place. Soils under viticulture have about one third the ¹³⁷ Cs content of soils with grass cover, indicating more severe erosion under cultivation. Caesium-137 profiles in alluvial fan and flood plain deposits correlate with sediment layers and known cultivation history.     

Recent Excavation and Recording at the New Neolithic Rock Art Site of Vallée Aux Noirs,Buthiers (Seine‐et‐Marne,France)

Following the exceptional discovery of Neolithic engravings on a boulder at Vallée aux Noirs in the Fontainebleau forest, south of Paris, an excavation trench was opened in order to access the buried part of the decorated rock panel and explore the stratigraphic context of the artwork. A palaeosol was found two metres below the modern ground level, underneath multiple layers of sterile sandy soil forming a very compact sequence from which only one archaeological artefact was recovered – an Iron Age fibula (c.200–300 BC). Dating of the palaeosol was attempted through two different methods: AMS dates from charcoal suggest a significant span from the Early Bronze Age to the Iron Age, while two more consistent OSL dates point to formation of the palaeosol during the Late Neolithic (3500–3000 cal BC). The entire engraved rock surface (16 m²), including its buried part, was fully recorded. Four main semiotic groups were identified: a typical fifth‐millennium crook‐hafted axe with a ring, two boats with steering oars, and a central, very tall human figure dominating the composition from its 3.5‐metre height.     

Chenopodium Seeds in Open-Air Archaeological Sites – How to Not Throw the Baby Out with the Bathwater

ABSTRACT

Differentiating between charred and uncharred plant remains may appear straightforward but for some taxa (here fat-hen, Chenopodium album type) can be very problematic. Recognition of the preservation state is obviously crucial for archaeobotanical data derived from dry, open-air sites. Fat-hen as a common weed, is also one of the most important components of a persistent soil seed bank. It is also a well-known food plant, gathered or cultivated. Numerous findings of fat-hen seeds in unclear states of preservation were noted in the Early Neolithic sites of the Linear Pottery culture in Kuyavia (N Europe). In previous studies such specimens were omitted as probably uncharred. Re-examination of Neolithic finds of fat-hen from that region showed the link of their abundancy with the earliest phases of the Neolithic occupation. The plant probably played an important role in the diet of the early Neolithic settlers there. It may indicate intensive use of local, open, fertile, probably alluvial areas. Distinguishing between ancient and modern specimens of that common weedy plant, producing large amounts of small, black, resistant seeds is thus very important, holding a great potential to shed new light on the origins of agricultural societies in this part of northern Europe.     

Simulation of adsorption of gold nanoparticles carried by gas ascending from the Earth’s interior in alluvial cover of the middle–lower reaches of the Yangtze River

The adsorption onto other minerals of charged gold nanoparticles, carried by gas ascending from the Earth’s interior, is an important component of their transport and deposition in surficial cover such as alluvial, aeolian, and glacial sediments. To simulate the adsorption of these particles, an experiment was conducted in which a flow of air that contained gold nanoparticles was passed upward through a sample of alluvium from the middle–lower reaches of the Yangtze River. These experiments showed that gold nanoparticles are adsorbed on kaolinite, halloysite, goethite, and hematite in the alluvial cover. Both the gold nanoparticles and minerals (i.e., kaolinite, halloysite, goethite, and hematite) carry surface charges that provide them with excellent adsorption properties. This study showed that the specific mineral composition of surficial alluvial cover affects the concentration of gold nanoparticles in the ascending gas. This phenomenon may plausibly be used in exploration for concealed gold, copper–gold, and silver–gold deposits in areas of thick alluvial cover. Geofluids (2010) 10 , 438–446