Obsidian hydration dating on the South Coast of Peru

We compare over 230 obsidian hydration readings from 30 individual site components from the Southern Nasca Region (SNR) with independent age estimates based on radiocarbon dates and temporally diagnostic artifacts. Although there are problems with small sample sizes, and readings must be adjusted for elevation, a very strong relationship accounting for nearly 90% of the total variation in the data set is found. This suggests that obsidian hydration dating (OHD) works in the SNR and is a viable means of independently estimating age. Residual values from our regression suggest that hydration age estimates are usually within 15% of the radiocarbon estimates. Finally, we present an equation other scholars can use to estimate age for Quispisisa obsidian in the SNR.     

A provenance study of archaeological obsidian from the Andahuaylas region of southern Peru

To date, most obsidian sourcing studies in the Andes have concentrated on the highlands and Titicaca Basin of far southern Peru and northern Bolivia. Toward achieving a more complete understanding of the region, this paper offers new data on the long-term prehistoric obsidian procurement and consumption patterns in the Andahuaylas region of the south-central Peruvian highlands. Obsidian sourcing data from Andahuaylas are particularly interesting since the area is centrally located among several important regional obsidian sources. A total of 94 obsidian samples from a range of sites of different temporal periods were chemically analyzed using portable X-ray fluorescence (PXRF), as well as laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The results demonstrate a number of interesting trends, the first of which is the long-term importance of the Potreropampa obsidian source to populations of the Andahuaylas region from at least the early Formative period (∼2500 BCE). Secondly, the results indicate that procurement strategies by local populations in Andahuaylas were primarily reliant on nearby (<150 km) obsidian sources. Finally, the paucity of more distant, yet widely exchanged, high quality obsidian (i.e., Chivay, Alca) confirm that as a region, Andahuaylas was more heavily connected economically (and likely culturally) with local areas to the south (Apurímac) and to the west (Ayacucho).     

Macusani obsidian from southern Peru: A characterization of its elemental composition with a demonstration of its ancient use

Transparent obsidian artifacts have been reported for the northern Lake Titicaca Basin. Based on instrumental neutron activation analysis (INAA) of these artifacts a distinct chemical group was identified. Yet, the location of the source of transparent obsidian in the southern Andes remained unreported in the archaeological literature. This paper reports on the chemical composition and geographic location of a source of transparent obsidian from the Macusani region of Peru. Through the use of INAA and portable X-ray fluorescence (PXRF) we demonstrate that Macusani obsidian or macusanite comprises (at least) two chemical groups. One of these groups was used for making artifacts during the Archaic Period. Artifacts made of this obsidian were found more than 120 km from the source and yet, one-third of the obsidian artifacts encountered at Macusani were from the non-local source of Chivay which is 215 km to the southwest.     

An archaeologically validated protocol for computing obsidian hydration rates from laboratory data

This paper reports the computation of hydration rate for Topaz Mountain obsidian from laboratory data, and a comparison with archaeological data from a well-dated site, Camels Back Cave, in western Utah. Topaz Mountain obsidian is found to be slow-hydrating, with a rate of 0.071 ± 0.021 μ/yr^½ at an effective hydration temperature of 16.01 °C. This rate agrees with a rate developed from archaeological data from Camels Back Cave within ∼6%. Activation energy of Topaz Mountain obsidian is 10370 ± 544 K, and its diffusion constant is (1.87 ± 9.13) × 10¹³ μ²/yr, both of which are independent of temperature. Its intra-source variability in hydration rate is very low (CV < 0.01), implying a low variability in intrinsic water. We present a model of chemical erosion which shows why earlier laboratory-determined rates were incorrect, and discuss the implications of our findings on the determination of experimentally derived rates in obsidian hydration dating.     

Accuracy of obsidian hydration dating based on obsidian–radiocarbon association and optical microscopy

Most archaeologists using obsidian hydration dating (OHD) in the United States develop hydration rates from association of obsidian hydration rims with dates based on radiocarbon, subsequently using the rate for chronometric analysis. The overall accuracy of the process has never been quantified. This paper reports an accuracy analysis in which sources of uncertainty are defined and modeled and their effects quantified. A Monte Carlo simulation is used to quantify errors from rate development, while uncertainties in age resulting from chronometric analysis are calculated analytically. For typical ranges of error values, hydration rate errors of ∼5% or less are achievable in the absence of systematic errors, with errors of chronometric age estimates ∼20–30% or less.     

Dating of 4th millennium BC pile-dwellings on Ljubljansko barje,Slovenia

We present absolute dates of seven late Neolithic pile-dwellings on Ljubljansko barje, Slovenia. They were settled from ca. 3600 to 3332 (±10) and from 3160 to 3071 (±14) cal BC, as shown by investigations of wood using dendrochronology and radiocarbon wiggle-matching. We defined eleven periods of intensive tree felling (and building activities) and one major settlement gap (when no trees were felled) from 3332 to 3160 cal BC. A major settlement gap presumably also followed after 3071 cal BC (i.e., after the end date of the investigated sites). Our investigations included over 2500 pieces of wood, mainly from the piles on which the dwellings were built. Among important wooden artefacts were a wheel with axle (one of the oldest preserved wheels in the world) and two dugout canoes, all from the settlement phase from 3160 to 3100 cal BC. As shown by parallel studies, the economy in the sites was characterized by copper metallurgy, skilful wood processing and use, cultivation of domestic plants, gathering of wild plants, animal husbandry, hunting and fishing. The settlements were contemporaneous with a number of sites in the north of the Alps, the younger ones coincided with the lifetime of the Neolithic Iceman (Ötzi). Since Ljubljansko barje has a strategic position at the crossroads between western central and (south) eastern Europe the presented absolute dates provide a basis for their comparison with other dated contemporaneous sites (in the west), to revise the chronology of similar sites in the (south) east (which are not yet exactly dated), and to evaluate their interconnection and roles in cultural development in prehistory.     

The source of obsidian artefacts found at East Chia Sabz,Western Iran

Excavations at the site of East Chia Sabz in western Iran uncovered deposits dating from the 9th through 7th millennium BC showing evidence of obsidian use. A total of twenty obsidian artefacts was found at the site and they were analyzed by X-ray fluorescence and neutron activation analysis. The results show all of the obsidian found at East Chia Sabz came from the Nemrut Da? source in southeastern Turkey located a distance of almost 750 km from East Chia Sabz. The results and their archaeological implications are discussed.     

Long-distance provenance for obsidian artifacts of Mesoamerica Preclassic and Early Classic periods found in the Los Naranjos Archaeological Park (Honduras)

Los Naranjos is one of the most important pre-Columbian human settlements of Honduras related to the south-easternmost border of the Mayan civilization. Although the archaeological site mostly spans from 850 BC to 1250 AD, the present obsidian study was only focused on the Preclassic and Early Classic periods (Jaral, 800–400 BC and Edén, 400 BC–550 AD) where undamaged blades and/or retouched obsidian flakes are rare. In this way, the INAA analyses of 17 obsidian samples, compared with major-trace elements data of Honduran and Guatemalan obsidian sources, are mostly representative of waste flakes. Lithic artifacts of Los Naranjos such as sandstones, basalts, and quartzites come from local geological outcrops; whereas, obsidian provenance has to be searched from sources which are located within a radius up to 300 km far away. San Luis, La Esperanza, and Güinope obsidian sources are located in Honduras while the three most exploited Highland Guatemalan obsidian outcrops, which have been dominating long-distance trade in the Maya area mostly for the Classic-Postclassic periods, are San Martin de Jilotepeque, El Chayal, and Ixtepeque. An Ixtepeque provenance, for all the investigated obsidian samples of Preclassic and Early Classic periods found in the Los Naranjos Archaeological Park, was established, thus emphasizing a long-distance source (180 km). This also confirms that Ixtepeque represents the most important provenance of the obsidian artifacts found in archaeological sites of Western and Central-Western Honduras. The possible role played by some of the most important rivers of Guatemala and Honduras as waterway networks of transport was finally pointed out. New INAA chemical data from the Honduran obsidian source of La Esperanza (“Los Hoyos”, 4 samples) are also reported in this paper.     

Through the Glass Darkly: Prehispanic Obsidian Procurement and Exchange in Southern Peru and Northern Bolivia

Recent discovery of the major geological sources of Central Andean obsidian permits a new understanding of the patterns of obsidian procurement and exchange by the Prehispanic societies of southern Peru and northern Bolivia. Based on the trace element analysis of obsidian artifacts from 160 archaeological sites, it can be established that the two major deposits of obsidian were being exploited by 9400 BP, and that volcanic glass was being transported over long distances throughout Andean prehistory. Inhabitants of the Cuzco region acquired most obsidian from the Alca source in central Arequipa, while those in the high plateau surrounding Lake Titicaca obtained most obsidian from the Chivay source in southern Arequipa. Obsidian evidence suggests close ties between the Cuzco and Circum-Titicaca regions throughout prehistory, except during the Middle Horizon (ca. 1400–1050 BP), when the expansion of the Huari and Tiahuanaco states disrupted this pattern.     

Osteological and paleodietary investigation of burials from Cova de la Pastora,Alicante, Spain

We present results of osteological and isotopic analyses of human remains from Cova de la Pastora (Alcoi, Alicante, Spain) and discuss the implications in light of a new sequence of radiocarbon dates indicating that the cave was used as a burial site in the Late Neolithic (ca. 3800–3000 cal BC), Chalcolithic (ca. 3000–2500 cal BC), Bell Beaker Transition (Horizonte Campaniforme Transicional - HCT; ca. 2500–2200 cal BC) and the Bronze Age (ca. 2200–1500 cal BC). Similarities in stable isotopic values of C and N indicate little variation in subsistence between men and women, and a similar nutritional base from the Late Neolithic to the Bronze Age. This pattern of stability is augmented by evidence of trauma and disease found on numerous skulls in the collection. Since no clear associations of specific grave goods with certain individuals based on sex or age could be determined, the only suggestion of social inequality lies in the burial practice itself, where certain individuals were interred in caves while others were not.     

Strofilas (Andros Island,Greece): new evidence for the cycladic final neolithic period through novel dating methods using luminescence and obsidian hydration

The recently excavated coastal prehistoric settlement of Strofilas on Andros Island (Cyclades, Greece) in the Aegean sheds new light on the transitional phase from the Final Neolithic to Early Cycladic period regarding masonry, fortification, and richly engraved rock art. The fortification possesses early evidence of preserved defensive architecture, as evidenced from the plethora of scattered finds from within and around the settlement. Important features are carvings on rock walls which mainly depict ships, animals, and fish. Initial archaeometric dating via the application of luminescence dating of two samples from the fortified wall bearing engraved ships, and by obsidian hydration of two blades employing the new SIMS-SS method (secondary ion mass spectrometry via surface saturation), has been undertaken to determine the site's chronology. The former yields an average date of 3520 (±540) BC and the latter an average date of 3400 (±200) years BC, both of which, within overlapping errors, suggest the main settlement occurred during the Final Neolithic.     

Comparison of XRF and PXRF for analysis of archaeological obsidian from southern Perú

Chemical sourcing is becoming an increasingly important component of archaeological investigation. Instruments used for elemental analysis generally must be operated in a controlled laboratory environment. Further, many methods require destruction of a small portion of the objects under investigation. These facts inhibit the application of chemical sourcing studies in a number of research contexts. Use of portable non-destructive instruments would resolve these issues. Sixty-eight obsidian artifacts from the site of Jiskairumoko, in southern Perú, were examined by X-ray fluorescence spectrometry (XRF) and portable X-ray fluorescence spectrometry (PXRF). Results were compared for consistency in terms of source determination and individual element concentrations. Both instruments determined that the same sixty-six artifacts derived from the Chivay obsidian source and both identified the same two artifacts that could not be assigned to source. Individual element comparisons showed significant differences, but these can be resolved through instrument cross calibration, and differences had no bearing on source identification. PXRF was found suitable for determining obsidian sources in southern Perú and for identifying specimens that require more sensitive analytical methods such as, instrumental neutron activation analysis (INAA). Regular use of Chivay at Jiskairumoko suggests consistent trade relationships developed during the Archaic.     

Vegetation history at the multi-period prehistoric complex at Ballynahatty,Co. Down,Northern Ireland

Palaeoecological methods can provide an environmental context for archaeological sites, enabling the nature of past human activity to be explored from an indirect but alternative perspective. Through a palynological study of a small fen peatland located within the catchment of a multi-period prehistoric complex at Ballynahatty, Co. Down, Northern Ireland, we reconstruct the vegetation history of the area during the early prehistoric period. The pollen record reveals tentative evidence for Mesolithic activity in the area at 6410–6220 cal BC, with woodland disturbance identified during the Mesolithic–Neolithic transitional period ca. 4430–3890 cal BC. A more significant impact on the landscape is observed in the Early Neolithic from 3950 to 3700 cal BC, with an opening up of the forest and the establishment of a mixed agricultural economy. This activity precedes and continues to be evident through the Mid-Neolithic during which megalithic tombs and related burial sites were constructed at Ballynahatty. Due to chronological uncertainties and a possible hiatus in peat accumulation in the fen, the contemporary environment of the Ballynahatty timber circle complex (constructed and used ca. 3080–2490 cal BC) and henge (dating to the third millennium cal BC) cannot certainly be established. Nevertheless, the pollen record suggests that the landscape remained open through to the Bronze Age, implying a long continuity of human activity in the area. These findings support the idea that the Ballynahatty prehistoric complex was the product of a gradual and repeated restructuring of the ritual and ceremonial landscape whose significance continued to be recognised throughout the early prehistoric period.     

Obsidian hydration dating by infrared spectroscopy: method and calibration

Low temperature (90–190 °C) hydrothermal experiments have been conducted on seven obsidians where composition of the glass varies significantly in the concentration of structural water within the unhydrated bulk material. Infrared transmission spectroscopy was used to track the diffusion of molecular water into the glass surface as a function of time and temperature. Long-term (60–360 days) hydration sequences at 90 °C show a t^0.6 time dependence for the mass uptake of molecular water that forms the hydration layer. The structural water concentration of the unhydrated bulk obsidian is highly correlated with the pre-exponential and activation energy and may be used to estimate the Arrhenius constants. In addition, secondary ion mass spectrometry (SIMS) hydrogen profiling of Napa Glass Mountain obsidian hydrated at 90 °C reveals that the early stages of diffusion exhibit a dynamic behavior that includes a fluctuating hydrogen concentration and a changing diffusion coefficient that slows with time.     

Long distance trinket trade: Early Bronze Age obsidian from the Negev

The discovery of three small obsidian flakes at the Camel Site in the central Negev, Israel, constitutes the first discovery of obsidian in Early Bronze Age contexts in the Negev and Sinai. Obsidian hydration analysis and X-ray microprobe analysis confirm the association of the artifacts with the site and the period, and indicate origins in Eastern Anatolia, in significant contrast to the exclusively Central Anatolian source of Southern PPNB obsidian. The structure of the obsidian trade system in the Early Bronze Age seems to contrast significantly with its Neolithic predecessor, and may be related to a system of pastoral nomadic exchange.     

Late Mesolithic burials at Casa Corona (Villena,Spain): direct radiocarbon and palaeodietary evidence of the last forager populations in Eastern Iberia

Current knowledge about the Mesolithic–Neolithic transition in the Central and Western Mediterranean European regions is deeply limited by the paucity of Late Mesolithic human osteological data and the presence of chronological gaps covering several centuries between the last foragers and the first archaeological evidence of farming peoples. In this work, we present new data to fill these gaps. We provide direct AMS radiocarbon dating and carbon (δ¹³C) and nitrogen (δ¹⁵N) stable isotope analysis were carried out on bone collagen samples of two single burials from the recently discovered open-air Late Mesolithic site of Casa Corona (Villena, Spain). The results shed new light on the chronology and subsistence patterns of the last Mesolithic communities in the Central Mediterranean region of the Iberian Peninsula. Radiocarbon results date the human remains and funerary activity of the site to 6059–5849 cal BC, statistically different from other Late Mesolithic sites and the earliest Neolithic contexts, and bridging the 500 yrs chronological gap of the Mesolithic–Neolithic transition from the area. Isotopic evidence shows that diet was based on terrestrial resources despite the proximity to the site of lagoon and marine ecosystems. This and previous isotope studies from the region suggest a lower reliance upon marine resources than for Atlantic and Cantabrian sites, although intra-regional patterns of neighbouring Mesolithic populations exhibit both fully terrestrial diets and diets with significant amounts of aquatic resources in them. We hypothesize that in the Central Mediterranean region of Spain the Late Mesolithic dietary adaptations imposed structural limits on demographic growth of the last foragers and favoured rapid assimilation by the earliest Neolithic populations.     

A multi-layered prehistoric settlement structure (tell?) at Niederröblingen,Germany and its implications

At least 15 settlement layers, deposited above each other from the early Neolithic (ca. 5300 cal BC) until Roman Imperial Times (ca. 400 cal AD), have been discovered at Niederröblingen, Germany. Constituting the longest duration of prehistoric settlement in central Europe so far known (ca. 4000 yrs), the site is thought to represent the first multi-layered settlement mound (tell?) north of the Alps. This implicates that the occurrence of settlement mound is not limited to the circum-Mediterranean area. The detailed chronology, based on archaeological, radiocarbon and OSL dating and supporting a Bayesian model, shows one clear occupational gap (early Neolithic) and a possible hiatus (Roman Times). Erosion phases of the settlement mound and the deposition of alluvial sediments (since Roman Imperial Times) in the surroundings resulted in an almost complete disappearance of the mound from the recent scenery. Being difficult to detect, similar sites might be present, undetected, in central Europe. Their discovery and study would enable the precise reconstruction of the settlement history as well as of the prehistoric man–environmental interactions at a high resolution.     

Roman Villa,Discovered at Bisley,Gloucestershire

In 1973 the Watch Hill barrow in St Stephen-in-Brannel, Cornwall was excavated and demonstrated to be a complex structure. However, at the time it was only possible to arrange two radiocarbon determinations, from the same pit in the base of the ditch. As part of postgraduate research carried out at the University of Exeter, the archive was revisited and funding obtained for a further four radiocarbon determinations from the ditch and central burial within the barrow. The six radiocarbon determinations together ranged between 2140 and 1680 cal. BC. The results are significant as they indicate that the site was in use over several centuries with the burial occurring towards the end of activity.     

Sources of Archaeological Obsidian on Sakhalin Island (Russian Far East)

Instrumental neutron activation analysis was performed on 79 obsidian tools and flakes from 35 sites on Sakhalin Island dating from Upper Paleolithic (c. 19,000 bp ) to Early Iron Age (c. 2000–800 bp ). Due to the absence of volcanic glass on Sakhalin Island, raw materials from the nearest obsidian sources on Hokkaido Island, such as Oketo, Shirataki, Tokachi-Mitsumata, and Akaigawa, were also analysed. A strong correlation between the chemical compositions of obsidian artefacts from Sakhalin and volcanic glass sources from Hokkaido was discovered. In particular, the Oketo and Shirataki sources were used for tool manufacturing throughout all of Sakhalin Island's prehistory. The distances between sources and archaeological sites range from 200–1000 km. The intensive exchange of raw materials continued and even intensified after the appearance of the La Pérouse (Soya) Strait between Hokkaido and Sakhalin about 10,000–8000 bp. The Sakhalin Island populations were deeply involved in the obsidian exchange network centered on Hokkaido.     

Prehistoric population history in eastern Fennoscandia

In this article, prehistoric population history in eastern Fennoscandia is modelled using summed probability distributions of radiocarbon dates. In addition, radiocarbon date distribution is compared with other proxy data. Different proxies seem to produce similar distributions, which enhances the overall reliability of the pattern. The results indicate that there was a very pronounced peak in the hunter–gatherer population slightly after 4000 cal BC. This peak seems to be linked to increased environmental productivity. The subsequent population decline culminated just before the local appearance of farming economies in different sub-areas, which is an interesting result in the wider northern and central European context. Along with the adoption of agriculture, new population growth began in eastern Fennoscandia.