Derek Hamilton

Similarities between contemporaneous occupations from the Promontory Caves in Utah and Franktown Cave in eastern Colorado provide evidence of a pre-A.D. 1300 migration of proto-Apachean speakers into the Rocky Mountain west using both Intermontane and Plains margin migration routes. Bayesian modeling of Promontory Culture AMS dates from Franktown Cave suggests a 40-85 year occupation starting in the early A.D. 13th century that likely overlaps the modeled 25-55 year occupation of Promontory Cave 1 during the late 13th century. Using moccasin size as a proxy for age, the complete Franktown Cave moccasin was likely made for a 4-5 year-old child. Isotopic values (δ13C) for bison leather from Franktown Cave suggest that bison from northern and southern herds were exploited and products made from their hides were discarded at the site. These data indicate the Promontory Culture group at Franktown Cave was mixed in age, suggesting migrants (rather than scouting groups) that traveled widely or had trade connections both north and south. Increased climate variability during the MCA-LIA transition in the 13th century may have contributed to social turmoil and decreasing human population in eastern Colorado, allowing early proto-Apacheans opportunity to move through the area as bison range expanded to the south.

Excavations at Black Loch of Myrton, Dumfries & Galloway are
revealing the very well-preserved remains of an Iron Age
settlement, the wetland context ensuring that the timber
structures have remained intact and that the detritus of daily
occupation survives for us to pick apart and understand. One of
the structures in this settlement is an exceptionally well-preserved
roundhouse, the material remains of which have been subjected
to a barrage of analyses encompassing the insect, macroplant,
bone and wood assemblages, soil micromorphology, faecal
steroids, radiocarbon-dating and dendrochronology. These will
enable us to address some of the key issues regarding the life
cycles of Iron Age roundhouses, from conception and
construction, use of internal space, nature of occupation and likely
function, through to abandonment. Critically, we are now able to
view that life cycle through the lens of a tightly-defined
chronology bringing us close to the ‘ …short-term timescales of
lived reality’ [Foxhall, L. 2000. “The Running Sands of Time:
Archaeology and the Short-Term.” World Archaeology 31 (3):
484–498].

Around the beginning of the 3rd millennium cal BC a cremation cemetery was established at Forteviot, central Scotland. This place went on to become one of the largest monument complexes identified in Mainland Scotland, with the construction of a palisaded enclosure, timber structures, and a series of henge monuments and other enclosures. The cemetery was established between 3080 and 2900 cal BC, probably in the 30th century cal BC, which is contemporary with the cremation cemetery at Stonehenge. Nine discrete deposits of cremated bone, representing the remains of at least 18 people, were identified. In most instances they were placed within cut features and, in one case, a series of cremation deposits was associated with a broken standing stone. This paper includes the first detailed assessment of the cremated remains at Forteviot and the features associated with the cemetery, and explores how the establishment of this cemetery may have been both a catalyst and inspiration for the elaborate monument building and prolonged acts of remembrance that occurred at this location over a period of almost 1000 years. The paper also outlines the parallels for Forteviot across Britain and, for the first time, draws together the dating evidence (including Bayesian modelling) for this major category of evidence for considering the nature of late 4th/ early 3rd millennium cal BC society. The results and discussion have wide implications and resonances for contemplating the establishment and evolution of monument complexes in prehistoric Britain and beyond.

Radiocarbon (14C) wiggle-match dating is a technique with a substantial potential to improve the precision of dating timbers in situations where dendrochronology is not tenable. However, one of the key reasons why obtaining a dendrochronological determination might be difficult is the short-lived nature of timbers on a range of archaeological sites, something that also affects the efficiency of the wiggle-match dating technique. Combined with the potential for high expense that the technique presents, it is paramount that wiggle-match dating research design has a good empirical basis. To this end we dated 50 consecutive, individual rings from a timber that grew during the Hallstatt radiocarbon calibration plateau (ca. 750–400 cal BC) in southwest Scotland. The results indicate that (1) the precision and accuracy of wiggle-match dates carried out on short-lived sequences during the Hallstatt plateau may suffer due to insufficient resolution of the calibration data, (2) sampling time-frames roughly equivalent to the underpinning calibration data are recommended (for the period in question this means decadal blocks), and (3) short-lived sequences are at risk of losing accuracy if the actual past trend of radiocarbon diverges from the mean of the radiocarbon calibration curve.

We review the history of Bayesian chronological modeling in archaeology and demonstrate that there has been a surge over the past several years in American archaeological applications. Most of these applications have been performed by archaeologists who are self-taught in this method because formal training opportunities in Bayesian chronological modeling are infrequently provided. We define and address misconceptions about Bayesian chronological modeling that we have encountered in conversations with colleagues and in anonymous reviews, some of which have been expressed in the published literature. Objectivity and scientific rigor is inherent in the Bayesian chronological modeling process. Each stage of this process is described in detail, and we present examples of this process in practice. Our concluding discussion focuses on the potential that Bayesian chronological modeling has for enhancing understandings of important topics.

The discovery of archaeological structures in North Uist in 1974 after storm damage led to the identification by Iain Crawford of a kerb cairn complex, with a cist and human remains. Six years later he went back, and over the next three years excavated another cist with human remains in its kerbed cairn, many bowl pits dug into the blown sand, and down to two late Neolithic structures and a ritual complex. He intensively studied the environmental conditions affecting the site and was among the first archaeologists in Scotland to understand the climate changes taking place at the transition between late Neolithic and the early Bronze Age. The deposition of blown sand and the start of the machair in the Western Isles, including the rise in sea-level and inundations into inhabited and farmed landscapes, are all part of the complex story of natural events and human activities. Radiocarbon dating and modern scientific analyses provide the detail of the story of periods of starvation suffered by the people that were buried on the site, of the movement away of the community, of their attempts of bringing the 'new' land back into cultivation, of a temporary tent-like structure, and of marking their territory by the construction of enduring monuments to the dead. Beverley Ballin Smith took up the mantle left by Iain Crawford and has brought this first monograph on his Udal project area to publication. She has extensive experience of working on, and publishing, other large multi-period sites. She is an archaeologist who lived and worked on Orkney for many years and has first-hand experience of the archaeology of Shetland, the UK, Faroes, Denmark, Norway and Sweden, and is now based in Scotland. Beverley is the Publications Manager at GUARD Archaeology Ltd and editor of ARO (Archaeology Reports Online), with the aim of disseminating information to relevant audiences. She undertakes specialist analysis of prehistoric pottery and coarse stone tools.

The work reported here is one of the  rst systematic radiocarbon dating studies of a Late Iron Age cremation burial cemetery. The Westhampnett cemetery in southern england was excavated before it was possible to date cremated bone. The 1st century BC date (Lt D1b-D2a) for the site proposed in the 1997 publication was based on brooches pres­ ent in the graves and their continental parallels. 44 of the 161 cremation burials were radiocarbon dated (27%) and the results modelled using Bayesian statistics. Two models are presented, the »Primary Model« and the »Charcoal Outlier Model«. The latter model addresses the potential problem of carbon exchange between the bioapatite (the datable fraction of the cremated bone) and the carbon (CO and CO2) from the fuel for the pyre, which could be earlier in date (i. e. an »old wood effect«). Both models are internally consistent and suggest the same end date for the use of the cemetery. However, the early start date suggested by the »Primary Model« is dif cult to reconcile with current typo-chronologies for the brooches. The start date indicated by the »Charcoal Outlier Model« is also earlier than expect­ ed but not incompatible with recent continental dating for one-piece  liform brooches. Whilst further studies are needed, it is clear that radiocarbon dating of cremated bone has great potential to help develop a more rigorous inde­ pendent chronological framework for the late iron age across europe.

This paper reviews the results of a long-term research project that used stable isotope analyses (δ13C, δ15N, δ34S) and Bayesian mixing models to better model the chronology for a presumed Viking Age cemetery at Hofstaðir, near Lake Mývatn in north-east Iceland. δ13C and radiocarbon dating indicated that many of the individuals consumed a large amount of marine protein, which results in a marine reservoir effect (MRE), making ages older than expected. In addition to the MRE, geological activity in the region has the potential to introduce massive quantities of radioactive ‘dead’ carbon into the freshwater system, resulting in a very large freshwater reservoir effect (FRE) that can offset radiocarbon ages on the order of a few thousand years. The radiocarbon dates of organisms that derive an unknown proportion of their carbon from both marine and freshwater reservoirs are extremely difficult to ‘correct’, or, more appropriately, model. The research not only highlights the complexities of dealing with multiple reservoirs, but also how important it is to develop models that are temporally and geographically relevant to the site under study. Finally, it shows how this data can be used to inform the development of chronological models for refining the dating for archaeological activity.

We review the history of Bayesian chronological modeling in archaeology and demonstrate that there has been a surge over the past several years in American archaeological applications. Most of these applications have been performed by archaeologists that are self-taught in this method because formal training opportunities in Bayesian chronological modeling are infrequently provided. We define and address misconceptions about Bayesian chronological modeling that we have encountered in conversations with colleagues and in anonymous reviews, some of which has been expressed in the published literature. Objectivity and scientific rigor is inherent in the Bayesian chronological modeling process. Each stage of this process is described in detail and we present examples of this process in practice. Our concluding discussion focuses on the potential Bayesian chronological modeling has for enhancing understandings of important topics.

An oak timber was discovered in 2013 within intertidal peats at the Bay of Ireland, Stenness, Orkney, representing a unique archaeological find. Subsequent excavation and rescue of the timber took place in 2014 to investigate its stratigraphical relationship before further eroding. Dendrochronological and morphological study identified the timber as a possible radially split log, c. 150 years of age when felled. No dendrochronological match was possible, and a wiggle-match date obtained provided a Later Mesolithic felling date of 4410–4325 cal BC. This timber is the first and only evidence so far for the use of oak in Mesolithic Orkney. The timber is significant palaeoecologically, suggesting oak may have been indigenous to Orkney. This adds to a growing argument for the existence of areas of “true woodland”. Pollen evidence shows the timber was deposited within reedswamp, fringed by willow-birch carr-woodland, with oak unlikely to have been growing in the immediate location. High microscopic and macroscopic charcoal values indicate Later Mesolithic communities' exerted influence on this wetland using burning as a tool for landscape modification. It is unknown what the timber represents; it may have been for construction purposes or as a marker/possible landing place showing the path to the Loch of Stenness.

The methodology for correcting radiocarbon (14C) ages for a marine reservoir effect is now reasonably well defined, while a similar correction for a freshwater reservoir effect has been demonstrated to be feasible under certain circumstances. However, adjusting radiocarbon ages to account for both sources of non-terrestrial carbon has proven challenging. Traditionally, the stable carbon (δ13C) or nitrogen (δ15N) isotope values in bone collagen can be used to determine the percentage of non-terrestrial protein in a person's diet, and the 14C age can then be amended accordingly. In this study, 46 bodies excavated from the medieval cemetery at Hofstaðir, near Lake Mývatn, in north-east Iceland were 14C-dated. A large number of individuals were found to pre-date the settlement (landnám) of Iceland in AD 871 ± 2, inferring that a
proportion of their diet must have contained some non-terrestrial protein that produced a reservoir effect. As freshwater fish from Lake Mývatn and marine fish have similar bone collagen δ13C values, using only one isotope to differentiate between the two food sources was not feasible. Therefore, δ13C, δ15N and δ34S isotope values for various terrestrial animals, and marine and freshwater fish were incorporated into the Bayesian mixing modelling program FRUITS (Food Reconstruction Using Isotopic Transferred Signals) to more accurately determine the diet of each individual. Their 14C ages were then corrected for both a freshwater and marine reservoir effect before Bayesian chronological modelling was employed to provide a more robust time frame for when the cemetery was in use. Previous findings suggested activity began
shortly after landnám, however this study indicates that the cemetery was in use between the 11th and 13th centuries.

Objectives:

A previous multi-isotope study of archaeological faunal samples from Skutustaðir, an early Viking age settlement on the southern shores of Lake Myvatn in north-east Iceland, demonstrated that there are clear differences in d34S stable isotope values between animals deriving their dietary protein from terrestrial, freshwater, and marine reservoirs. The aim of this study was to use this information to more accurately determine the diet of humans excavated from a nearby late Viking age churchyard.

Materials and Methods:

d13C, d15N, and d34S analyses were undertaken on terrestrial animal (n=39) and human (n=46) bone collagen from Hofstaðir, a high-status Viking-period farmstead 10 km north-west of
Skutustaðir.

Results:

d34S values for Hofstaðir herbivores were 6‰ higher relative to those from Skutustaðir (d34S: 11.4 ± 2.3‰ versus 5.6 ± 2.8‰), while human d13C, d15N, and d34S values were broad ranging (-20.2‰ to -17.3‰, 7.4‰ to 12.3‰, and 5.5‰ to 14.9‰, respectively).

Discussion:

Results suggest that the baseline d34S value for the Myvatn region is higher than previously predicted due to a possible sea-spray effect, but the massive deposition of Tanytarsus gracilentus (midges) (d34S: -3.9‰) in the soil in the immediate vicinity of the lake is potentially lowering this value. Several terrestrial herbivores displayed higher bone collagen d34S values than their contemporaries, suggesting trade and/or movement of animals to the region from coastal areas. Broad ranging d13C, d15N, and d34S values for humans suggest the population were consuming varied diets, while outliers within the dataset could conceivably have been migrants to the
area.

Previous stable isotope studies of modern and archaeological faunal samples from sites around Lake Mývatn, within the Mývatnssveit region of northeast Iceland, revealed that an overlap existed between the δ15N ranges of terrestrial
herbivores and freshwater fish, while freshwater biota displayed δ13C values that were comparable with marine resources. Therefore, within this specific ecosystem, the separation of terrestrial herbivores, freshwater fish, and marine fish as components of human diet is complicated when only δ13C and δ15N are measured. δ34S measurements carried out within a previous study on animal bones from Skútustaðir, an early Viking age settlement on the south side of Lake Mývatn, showed that a clear offset existed between animals deriving their dietary resources from terrestrial, freshwater, and marine reservoirs. The present study focuses on δ13C, δ15N, and δ34S analyses and radiocarbon dating of human bone collagen from remains excavated from a churchyard at Hofstaðir, 5 km west of Lake Mývatn. The results demonstrate that a wide range of δ34S values exist within individuals, a pattern that must be the result of consumption of varying proportions of terrestrial-, freshwater-, and marine-based resources. For that proportion of the population with 14C ages that apparently predate the well-established first human settlement of Iceland (landnám) circa AD 871 ± 2, this has enabled us to explain the reason for these anomalously old ages in terms of marine and/or freshwater 14C reservoir effects.

ABSTRACT.We present the first radiocarbon dates from previously unrecorded, secondary burials in the Cardamom Mountains,Cambodia. The mortuary ritual incorporates nautical tradeware ceramic jars and log coffins fashioned from locally harvested trees as burial containers, which were set out on exposed rock ledges at 10 sites in the eastern Cardamom Massif. The suite of 28 14C ages from 4 of these sites (Khnorng Sroal, Phnom Pel, Damnak Samdech, and Khnang Tathan) provides the first estimation of the overall time depth of the practice. The most reliable calendar date ranges from the 4 sites reveals a highland burial ritual unrelated to lowland Khmer culture that was practiced from cal AD 1395 to 1650. The time period is concurrent with the 15th century decline of Angkor as the capital of the Khmer kingdom and its demise about AD 1432, and the subsequent shift of power to new Mekong trade ports such as Phnom Penh, Udong, and Lovek. We discuss the Cardamom ritual relative to known funerary rituals of the pre- to post-Angkorian periods, and to similar exposed jar and coffin burial rituals
in Mainland and Island Southeast Asia

Krus AM, Cook R, Hamilton D. 2015. Bayesian Chronological Modeling of SunWatch, a Fort Ancient Village in Dayton, Ohio. Radiocarbon 57(5):965-977.

Radiocarbon results from houses, pits, and burials at the SunWatch site, Dayton, Ohio, are presented within an interpretative Bayesian statistical framework. The primary model incorporates dates from archaeological features in an unordered phase and uses charcoal outlier modeling (Bronk Ramsey 2009b) to account for issues of wood charcoal 14C dates predating their context. The results of the primary model estimate occupation lasted for 1–245 yr (95% probability), starting in cal AD 1175–1385 (95% probability) and ending in cal AD 1330–1470 (95% probability). An alternative model was created by placing the 14C dates into two unordered phases corresponding with horizontal stratigraphic relationships or distinct groups of artifacts thought to be temporally diagnostic. The results of the alternative model further suggest that there is some temporal separation between Group 1 and Group 2, which seems more likely in the event of a multicomponent occupation. Overall, the modeling results provide chronology estimates for SunWatch that are more accurate and precise than that provided in earlier studies. While it is difficult to determine with certainty if SunWatch had a single-component or multicomponent occupation, it is clear that SunWatch’s occupation lasted until the second half of the AD 1300s.

Radiocarbon dating was long neglected in Iron Age research, with dates on the ‘Hallstatt plateau’ (800–400 BC) considered too broad to be useful compared to artefact typo-chronologies. Such views are now untenable. Around fifty British Iron Age settlements and cemeteries have been dated using Bayesian methodologies, yielding two important general results: (1) typological dating produces sequences that are regularly too late; and (2) many phenomena, from chariot burials to settlement shifts, represent brief horizons, rather than being long lived. Drawing on a selection of studies, this article explores the impact of Bayesian modelling on British Iron Age studies. It highlights potential pitfalls and issues that must be considered when dating the period, illustrates some major successes and looks to the future.

We present the first radiocarbon dates from previously unrecorded, secondary burials in the Cardamom Moun- tains, Cambodia. The mortuary ritual incorporates nautical tradeware ceramic jars and log coffins fashioned from locally har- vested trees as burial containers, which were set out on exposed rock ledges at 10 sites in the eastern Cardamom Massif. The suite of 28 14C ages from 4 of these sites (Khnorng Sroal, Phnom Pel, Damnak Samdech, and Khnang Tathan) provides the first estimation of the overall time depth of the practice. The most reliable calendar date ranges from the 4 sites reveals a high- land burial ritual unrelated to lowland Khmer culture that was practiced from cal AD 1395 to 1650. The time period is con- current with the 15th century decline of Angkor as the capital of the Khmer kingdom and its demise about AD 1432, and the subsequent shift of power to new Mekong trade ports such as Phnom Penh, Udong, and Lovek. We discuss the Cardamom rit- ual relative to known funerary rituals of the pre- to post-Angkorian periods, and to similar exposed jar and coffin burial rituals in Mainland and Island Southeast Asia.

The Cardamom Mountain Jar and Coffin burial site of Phnom Khnang Peung is the most extensive example
of the distinctive burial ritual first reported by Beavan et al. (2012a). The 40 intact Mae Nam Noi and late Angkorian-era
ceramic jars used as burial vessels held a total of up to 152 individuals, representing the largest corpus of skeletal remains of
any of the 10 known Jar and Coffin burial sites that have been discovered in the eastern ranges of the Cardamom Mountains
of Cambodia. We report here on the radiocarbon dating of this site and notable burial phenomena, using a Bayesian approach
to model the start and end date of activity as well as its overall span. The results of the dating and Bayesian analyses indicate
that the Phnom Khnang Peung site’s earliest burials began cal AD 1420–1440 (95% probability). Interestingly, the concentration
of burial activity spans only 15–45 years (95% probability), despite the large number of inhumations at the site. The
14C chronology presented for the site places the Highland burial ritual coincident with a period of economic, political, and
societal transformations in the lowland Angkorian polity, but the unique burial practice and trade relationships evidenced by
the burial goods and maritime trade ware ceramics employed in the burial ritual suggest these Highland people were a culture
apart from Angkorian cultural influences.

Correcting radiocarbon (14C) ages for a marine reservoir effect is now reasonably well defined, while a similar correction for a freshwater reservoir effect has been demonstrated to be feasible under certain circumstances. However, adjusting radiocarbon ages to account for both sources of non-terrestrial carbon has proven challenging. Traditionally, δ13C or δ15N isotope values in bone collagen can be used to determine the percentage of non-terrestrial protein in a person’s diet, and the 14C age can then be amended accordingly. In this study, 46 bodies excavated from the medieval cemetery at Hofstaðir, near Lake Mývatn, in north-east Iceland were 14C-dated. Many individuals were found to pre-date the settlement of Iceland in AD 871 ± 2, inferring that a proportion of their diet must have contained some non-terrestrial protein. δ13C, δ15N and δ34S isotope values for various terrestrial animals, and marine and freshwater fish were incorporated into the Bayesian mixing modelling program FRUITS (Food Reconstruction Using Isotopic Transferred Signals) to more accurately determine the diet of each individual. Their 14C ages were then corrected for both a freshwater and marine reservoir effect before Bayesian chronological modelling was employed to provide a more robust time frame for when the cemetery was in use.

This study provides an assessment of the temporal changes in ∆R, which is the local deviation from the global surface water marine reservoir effect (MRE), in the Point Barrow area of the Alaskan Arctic, a coastal archaeological area that has experienced severe erosion accelerated by global warming. A total of 26 samples were submitted for radiocarbon (14 C) dating from eight secure Thule (AD 1000-1750) archaeological contexts, and specifically from archaeological features with paired processed seal and caribou bones that had been frozen in situ. This new approach towards ∆R estimation provides a best-fit local correction for the 14 C dating of human populations by focusing on the marine mammal (seals) predominantly consumed by the Thule (Coltrain et al. 2016). The weighted-mean ∆R value on these pairs is 450 ± 84 yr, which is about 50 years less than the weighted-mean (506 ± 69 yr) for the Point Barrow area calculated through 14 C measurements from four known-age bivalves collected in AD 1913 (McNeely et al. 2006). The effects of using this new ∆R value for calibration was assessed through the Bayesian chronological modeling of 54 14 C measurements from samples of human skeletons interred in the Nuvuk cemetery at Point Barrow, the largest ancient cemetery in northwest Alaska and traditionally thought to date to the Thule and earlier Birnirk (AD 500-1000) periods.