Historical Survey and Chronology of Bonajuto Chapel in Catania,Italy

Located in the historical center of Catania, Italy, in the Civita district, the Bonajuto Chapel is one of the oldest and best-conserved buildings of the city, which has survived the numerous earthquakes that struck eastern Sicily during the medieval and the modern ages, such as those particularly devastating in 1169 and 1693. However, both the date of this small monument, as well as its original use, still remain uncertain, as literary and documentary evidence are scarce and fragmentary. Most historians, analyzing prevalently the stylistic and constructive aspects, interpreted the chapel as a place of worship and assigned its construction to a rather long period of the early Middle Ages, from the 5th or 6th centuries ad to the 8th or 9th centuries ad—the phase during which the island was under the Byzantine domination. The excavations carried out in 1930 to 1939 and the last restoration works (in 2003) have not provided explicit chronological data. Its age determination is considered essential for a better knowledge of the real influence of this domination on the architecture of the Island. Therefore, a multidisciplinary and accurate analysis of the building using the existing bibliography has been carried out also in order to understand the functional and morphological transformations of the chapel during its long life. The thermoluminescence absolute dating methodology applied to some brickwork elements of the construction, has placed the monument chronology in a period of time that is notably shorter than that previously noted here. These new data, with the study of the architectural structure, have made a significant step forward in the knowledge of the chapel history.     

Byzantine–Early Islamic agricultural systems in the Negev Highlands: Stages of development as interpreted through OSL dating

Abstract

An extensive survey followed by OSL (optically stimulated luminescence) dating of loess accumulation in agricultural terraces at six Byzantine and Early Islamic sites in the Negev Highlands revealed clear stratigraphic and chronological sequences. Traditionally dated to the 1st–7th centuries a.d., results from the present study demonstrate that the construction and use of largescale agricultural systems took place in the 4th–11th centuries a.d. This new chronology provides the framework for a more precise interpretation of the circumstances of construction and demise of largescale agriculture in the Negev Highlands. The agricultural fields were exploited continuously, yet ancient farmers had to confront the environmental hazards of occasional intensive floods, successive years of drought, and a constant process of loess accumulation and erosion. The constant maintenance and repair of fields necessitated an investment of labor. However, it seems that the expansion of ancient agriculture was part of the natural growth and development of Byzantine settlements in the Negev, and not the outcome of planned government enterprise. The agricultural systems were abandoned in the course of the 11th century a.d. and sporadically reused by pastoral nomads.     

A 28,000 year old excavated painted rock from Nawarla Gabarnmang,northern Australia

We report new archaeological excavations from northern Australia revealing part of a charcoal design likely to be c. 28,000 years old (and chrono-stratigraphically constrained within the period 15,600–45,600 cal BP) on a small rock slab fallen from the ceiling at the rockshelter of Nawarla Gabarnmang in Jawoyn country, Arnhem Land. This represents the oldest confirmed pictograph in Australia.     

Should dates trump context? Evaluation of the Cave 7 skeletal assemblage radiocarbon dates

“Massacre” was the accepted interpretation for a prehistoric skeletal assemblage of around 90 individuals from Cave 7 in the SE Utah of the North American Southwest since the 1890s. Coltrain and others (Journal of Archaeological Science 39, 2220–2230) rejected this account based on a dispersed suite of AMS radiocarbon dates on purified bone collagen from the interred individuals. Since dates from skeletons exhibiting perimortem damage were scattered across some 400 radiocarbon years, Coltrain et al. argued for multiple interments of victims of violence and related kin spread across several centuries. The temporal placement of interment events in Cave 7 clearly cannot be known independent of radiocarbon assays but such assays should not be privileged above contextual information about which individuals were interred together unless verified by an independent dating laboratory. Only by ignoring important information about burial context in the 1893 field record can the dates of Coltrain et al. be accepted as accurate estimates of time of death. We redated residual collagen from 11 of the Cave 7 individuals because of significant contextual anomalies with some of the prior results. The new assays combined with contextual evidence demonstrate that some of Coltrain et al.’s dates are either too old or too young; the dates are neither sufficiently accurate (true estimates of sample age) nor sufficiently precise (small confidence intervals) to refute a single-event massacre or to confirm multiple interment events in Cave 7. Nonetheless, dates that meet these criteria disclose at least two interment events, a large one of mostly adult males, many exhibiting perimortem damage (a massacre assemblage), and a small one consisting of an adult female with three children. A third interment event of a few adult females and child is possible based primarily on context since the date distribution in this case overlaps substantially with that of the massacre victims; context also hints at other interment events. Aside from chronology we clarify the number of Basketmaker individuals interred at the site and the incidence of perimortem violence. A single-event mass killing continues to be the most likely interpretation for around 58 individuals, mostly adult males (at least 35) but also adult females and children. This incident occurred between cal. AD 20–80 and doubtless had a significant social impact at the time because of its scale, reverberating throughout the early farming communities of the Southwest.     

Subterranean transport and deposition of quartz by ants in sandy sites relevant to age overestimation in optical luminescence dating

An artificial layered sandy site was created using a combination of native sand and colored sand (3 parts native uncolored quartz, 1 part colored quartz) in Apalachicola National Forest near Tallahassee, Florida. Twelve layers of sand, each 1 by 1 m in horizontal extent by 10 cm in thickness were emplaced to a depth of 2 m followed by implantation at the surface of a Florida harvester ant (Pogonomymrex badius) colony (the lower two layers were 50 cm thick). The colony excavated a nest, and after 7 months, the sand layers were excavated to the base to test the hypothesis that sand grains were moved upward within the ant nest without reaching the surface. The ants penetrated 11 of the 12 colored layers reaching a depth of 130 cm. Thirty nine sticky-acetate peels of ant chamber floors were collected and colored sand grains were counted under a microscope. More than 16,000 grains were identified in layers that did not originally host them. Of these, more than 80% were unambiguously moved upward. This means that possibly as many as 54,000 upwardly mobile grains were present (ratio of 3:1 uncolored to colored). In relation to optical luminescence (OSL) dating, this means that grains that would not have been optically zeroed by transport to the surface (defined here as subterranean-transported) were present in abundance, and that if the site was ancient, there would have been found many grains that were older than the layers they presently reside in, even if only one colony of harvester ants had disturbed the layers. This is in addition to the fact that backfilling of chambers and tunnels may contribute even more significantly to the presence of a subterranean-transported component of an OSL sample. We conclude that ants can significantly affect the age distributions in sandy archaeological sites. Multiple examples of such disturbances have been documented in the literature. Most relevant to our results are recent studies of the OSL chronology of Pre-Clovis-age and Palaeoindian age archaeological sites in sandy environments in North America that may have been compromised by ant bioturbation of quartz sand grains. Here we have examined in detail the potential effects of one episode of ant nest-building on the age overestimation of affected sediments. From this we found that as few as 12 episodes of bioturbation involving backfilling of chambers in the same volume of sand could lead to the presence of 1 contaminant grain per 50 grains of sample.     

Spatial and temporal variety of prehistoric human settlement and its influencing factors in the upper Yellow River valley,Qinghai Province,China

We report an investigation of forty-two prehistoric sites in the upper Yellow River valley located in Guide, Jianzha, Hualong, Xunha and Minhe, Qinghai Province, China, including forty-four new radiocarbon dates from twenty-four sites, review published archaeological surveys and radiocarbon dates, analyze landform features and discuss the reasons for spatial and temporal variety of regional prehistoric human settlement. Our results suggest that people occupied the upper Yellow River valley during the early Holocene, but a continuous archaeological record begins only after about 5500 Cal yr BP. Thereafter, the intensity of prehistoric human settlement in the area is varied. Neolithic human settlement spread northwestward to high altitude areas of the upper Yellow River valley during early-mid Majiayao and Qijia periods, but moved southeastward to lower locations in the area during late Majiayao period. During the Bronze period, two coeval archaeological cultures, the Kayue and Xindian, occupied the upper Yellow River Region. Kayue archaeological sites are numerous and widely distributed in the high areas of the upper Yellow River, while Xindian sites are restricted to the lowest basin of the region. Variation in site density and location are likely the result of changing paleoclimate and technology.     

Laser ablation depth profiling of U-series and Sr isotopes in human fossils

We have explored laser depth profiling to obtain data sets for U-series as well as Sr analyses. Laser probing with an 81 μm spot size allows for the exploration of low uranium domains of up to 400 μm below the outer surface in tooth enamel. These low U domains will contain Sr isotope compositions of the individual, that are least affected by diagenetic Sr overprints. The small holes drilled for U surveying are not visible to the naked eye. Using larger spot sizes of around 233 μm, laser drilling can be used to obtain reliable U-series isotope data to a depth of approximately 1000 μm in enamel and around 1300 μm in bone. Furthermore, meaningful ⁸⁷Sr/⁸⁶Sr isotope data can also be obtained with this spot size. Using our sampling strategy, the overall damage to a human tooth is minute, as demonstrated on a Neanderthal tooth from Moula-Guercy. We expect that laser ablation depth profiling will become routine for gaining insights into the age of human fossils and the migrations of ancient humans.     

Preliminary U-series and Thermoluminescence dating of excavated deposits in Liang Bua sub-chamber,Flores, Indonesia

We report the results of a test excavation of deposits in a limestone cave sub-chamber located beneath the main chamber of Liang Bua, Flores, Indonesia; the discovery site of the small hominin species, Homo floresiensis. Well-preserved remains of extinct Pleistocene fauna and stone artefacts have previously been identified on the surface of a sediment cone within the sub-chamber. Our excavation of the deposits, at the base of the sediment cone in the sub-chamber (to 130 cm depth) yielded only a few fragmentary bones of extant fauna. Uranium/Thorium (U-series or U/Th) dating of soda straw stalactites excavated from 20 to 130 cm in depth demonstrates that the excavated sediments were deposited during the Holocene. Red Thermoluminescence (TL) dating of the sediments at the base of the excavation (130 cm depth) indicates these sediments were last exposed to sunlight at 84 ± 15 ka (thousand years), similar to red TL ages of cave sediments from the main chamber. Together, these results indicate that the surface faunal remains, which are morphologically analogous to Pleistocene finds from the main chamber excavations, were transported to the sub-chamber relatively recently from the main chamber of Liang Bua and probably originated from conglomerate deposits at the rear of the cave and from deposits around the front entrance. There is no evidence for hominin occupation of the sub-chamber, instead it seems to have acted as a sink for cultural materials and fossil remains transported from the surface via sinkholes. Despite the small number of finds from the test excavation, it is possible that more extensive excavations may yield additional transported cultural and faunal evidence at greater depths.     

Lichenometric dating and the nature of the excavation of the Huashan Grottoes,East China

The present study aims to identify the timing of the Huashan Grottoes' excavations using the lichenometric dating method. A total of 96 maximum inscribed circle diameters of Rhizocarpon geographicum growing on the ancient architectures and the walls of entrances are measured in the Huashan Grottoes area of southern Anhui, East China. The results show that the period of the grottoes' excavation is estimated to be 450–335 yr BP, or the middle and late Ming Dynasty (1552–1667 AD). The lichenometric dating results are also validated by a lithologic comparison of the grottoes and the surrounding ancient architectures, as well as by the studies on the historical documents and the fragments of ancient porcelain in the grottoes. Furthermore, we infer that the excavation of the inner grottoes might have lasted till the Qing Dynasty (1636–1912 AD), because the lichens chosen for dating are mainly at the grottoes' entrances. The wider significance of this work is that it demonstrates, for the first time, lichenometric dating can be applied in the historical studies on the ancient architectures in East China with a relatively warm and humid climate.     

‘Old wood’ effect in radiocarbon dating of prehistoric cremated bones?

Numerous reports of successful radiocarbon dating of cremated bones have emerged during the last decade. The success of radiocarbon dating cremated bones depends on the temperature during burning and the degree of recrystallisation of the inorganic bone matrix. During cremation bones undergo major morphological and mineralogical changes which have raised some interesting questions and discussion on the origin of the carbon source in archaeologically cremated bones. Recent laboratory experiments reveal that the properties of the combustion atmosphere play a significant role regarding the source carbon in cremated bones. Thus radiocarbon dating cremated bones is potentially dating the wood used for the cremation fire. Here we compare a high precision radiocarbon dated human bone with an associated dendrochronological age from an oak coffin. We find that the age discrepancy between the dendrochronological age and the cremated bone of 73 ± 26 ¹⁴C yr is best accounted for by the so called ‘old wood’ effect.