Improvements in Archaeomagnetic Dating in Western Europe from the Late Bronze to the Late Iron Ages: An Alternative to the Problem of the Hallstattian Radiocarbon Plateau

We present a new curve of the directional secular variation of the geomagnetic field in Western Europe between 1500 bce and 200 ce . Its computation relies on a Bayesian framework. The fast secular variation during the Late Bronze and Early Iron Ages makes archaeomagnetic dating efficient with a respective precision of 150–200 and 60–100 years during these periods. The Bayesian method also provides posterior date distributions that refine the dating of reference data, especially during the period of the Hallstattian radiocarbon plateau. Archaeomagnetism becomes a valuable alternative to radiocarbon and will help to improve the archaeological chronologies.     

Contemplating the history and future of radiocarbon dating in the American Southeast

We consider the history, present, and future of radiocarbon dating in the American Southeast. We point out some of the past and present flaws related to archaeological research and dating. Our approach to this review is rooted in the perspective that each radiocarbon date collectively adds to our knowledge of the region and not just a particular site. Based on our observations, we suggest some “good” practices with respect to certain aspects of radiocarbon dating. Our concluding discussion considers Bayesian chronological analysis and the growing contribution of chronological modeling to the Southeast.     

A Bayesian approach to rapid seismic vulnerability assessment at urban scale

The seismic vulnerability of city centers is commonly assessed by extending the study methods applied to single buildings to urban aggregations. This approach is not always applicable at territorial scale, as it is uneconomical in terms of time and costs. An innovative method provides reasonable large-scale a priori estimation of parameters not directly evaluable from the exterior of buildings by elaborating values which can be measured from the outside. Those parameters are treated as continuous variables, by assigning them a suitable probability density function. The Bayesian approach is adopted, which allows the update of initial hypotheses by using new data gathered during on-site surveys. In this regard, a rapid survey form for the on-site data collection is proposed. An example of its application to a façade of a building structural unit in Santo Stefano di Sessanio in L’Aquila province (Italy) is proposed, showing promising preliminary results for buildings belonging to Italian historical centers.     

The emergence of agropastoralism: Accelerated ecocultural change on the Andean altiplano, ∼3540–3120 cal BP

In the fourth millennium BP, there were major environmental and cultural changes on the Andean altiplano of South America, but the chronology remains vague. A recent synthesis describes a slow, gradual transition from hunting and gathering to agropastoralism. This proposal is tested by refining the date of the onset of more humid and stable conditions, around 3550 cal BP, based on a Bayesian model of 26 dates from Lake Wiñaymarka and an updated calculation of the lacustrine offset. This is compared to Bayesian models of 191 dates from 20 archaeological sites, which incorporate a number of recently processed radiocarbon dates. A synthesis is presented of 15 full coverage surveys, a summed probability distribution, and a Bayesian model of the transition to ceramics, which together support a scenario of a very rapid demographic increase. Fourteen models from archaeological sites are cross-referenced in a composite model, which identifies a brief, altiplano-wide emergence of agropastoralism with starting and ending boundaries of 3540 and 3120 cal BP, respectively. This starting boundary correlates strongly with the onset of improving environmental conditions, indicating synchronous cultural and environmental change. The suite of accelerating cultural changes included a marked reduction in mobility, a demographic surge, increased subsistence diversity, the adoption of ceramics, farming and the integration of camelid herding into a remarkably resilient economic strategy still in use today. This is a highly relevant but yet to be used comparative case study for the variable tempos of ‘big histories’, and ecocultural interactions that generate rapid, emergent episodes of wide-spread and enduring cultural change.     

14C and Maya Long Count Dates: Using Bayesian Modelling to Develop Robust Site Chronologies

Bayesian statistics has now demonstrated its strong utility in archaeology, specifically through software that conditions radiocarbon data. Only recently has this technology been applied within Maya archaeology, however, in part because the Maya calendar provides a much greater resolution in dating archaeological events than is possible with radiocarbon data. The Long Count in particular allows for the assignment of some events relative to each other, accurate to the day. In this paper, a new approach is presented to incorporate robust records of both in the same Bayesian analysis through the OxCal software. The results do call for a reconsideration of the earliest radiocarbon studies in the Maya area from the 1960s, as well as the latest attempts to corroborate the currently popular calendar correlation known as the GMT. This new study demonstrates the value of the approach and corroborates the 1σ accuracy of the GMT, while at the same time opening up the possibility of revision by 20 or more years.     

The Comings and Goings of Sheep and Pottery in the Coastal Desert of Namaqualand,South Africa

This paper evaluates chronological trends in the presence and absence of domestic animal bone (sheep, goat, and cattle) and pottery in Namaqualand, the proposed gateway to the rest of South Africa for early herders or hunter-gatherers with sheep and ceramics. We update date calibrations with local ΔR corrections and mixtures of recent calibration curves and include five previously unpublished dates. We use histograms of calibrated medians, sorted in 100-year bins, to assess sustained regional patterns with dates associated with domestic animal bone and pottery (n = 73). While too small to be useful as a population proxy, the current set of dates does reveal three pulses of occupation separated by two clear gaps, which we evaluate with a Bayesian model of three sequential phases. The model's boundaries are used as estimates of the dates of Early (AD 80–210), Middle (AD 490–790), and Late (AD 1180–1690) occupational phases separated by two substantial lapses of 280 and 380 years, respectively. The alternating phases of presence and absence are suggestively correlated with climate shifts, leading to a discussion of the idea that effective moisture was a crucial factor in choosing whether to occupy Namaqualand. The set of archaeological dates has greater temporal and spatial resolution than many regional climate data, so we suggest that these trends may more accurately reflect the variable conditions specific to Namaqualand, at least until they are refined by future climate research.     

Bayesian Parameter Identification and Model Selection for Normalized Modulus Reduction Curves of Soils

This work develops a procedure that involves the use of Bayesian approach to quantify data scatterness, estimates the optimal values of model parameters, and selects the most appropriate model for the construction of normalized modulus reduction curves of soils. The proposed procedure is then demonstrated using real observation data based on a set of comprehensive resonant column tests on coarse-grained soils conducted in the study.     

Lichenometric constraints on the age of the Huashan Grottoes, East China

Lichenometry is a method of dating that has been widely used in glaciated areas for determining the minimum age of exposure of a geomorphic landform during the late Holocene. This paper presents a regional calibration data set of lichen thallus sizes versus rock surface ages for the Huashan area, East China, based on measurements of yellow-green Rhizocarpon lichens on the known-age substrates at eight sites. An empirical relationship between thallus sizes and rock surface ages was established using both the traditional regression and the Bayesian approaches. Using the Bayesian calibration, the minimum age of the Huashan Grottoes was dated from 450 ± 60 to 330 ± 60 years ago, corresponding to the late Ming Dynasty (AD 1477–1632). These dates are generally consistent with those predicted from the regression-based linear growth curve. Our results suggest that applications of this technique can be safely extended to the non-glaciated areas.     

中国最早“失镴法”春秋中期“蛇网盖冠龙虎方壶”的铸法论证

蛇网盖冠龙虎方壶等铜器上的透空精饰,并非“失蜡法”或“失铅法”所制,而为“失镴法”精心杰作。     

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.