Radiocarbon and U-series dating of the endemic deer Praemegaceros cazioti (Depéret) from “Grotta Juntu”, Sardinia

Radiocarbon and U-series methods (²³⁰Th/U and ²³¹Pa/²³⁵U) for absolute age determination have been applied to some fossil samples from Grotta Juntu, in North Eastern Sardinia (Italy). The remains belong to the endemic deer species Praemegaceros cazioti, which is here represented by an almost complete skeleton. The three dating methods lead to concordant ages of about 7500 years BP, indicating that the skeleton was maintained as closed system after burial. Taking into consideration these results, Praemegaceros cazioti from Grotta Juntu is now the youngest representative of this species in Sardinia.     

Luminescence chronology of the medieval citadel of Termez,Uzbekistan: TL dating of bricks masonries

Among the dating methods in archaeology, thermoluminescence (TL) is widely developed. The present research concerns the construction chronology of the citadel of Termez (Uzbekistan) in the medieval period. On the methodological side along the TL study, we had to take into account two decisive factors that are expected to affect the accuracy: control of anomalous fading on the polymineral fraction (quartz and feldspars) and the effect of thermal treatments on the luminescence properties of the dated material. With regard to the determination of the annual dose, difficulties, associated with the evolution of the radiochemical composition of the dated samples and their environment over time, were overcome.     

Forensic Ar/Ar dating: a provenance study of Middle Stone Age obsidian artifacts from Ethiopia

Obsidian sourcing based on geochemistry is widely applied to reconstruct commerce patterns and dissemination of early hominid groups. Due to problems concerning potential intra-source variability or homogeneity of a geological source over large areas, parameters additional to this classical approach are desirable. Here we present the first ⁴⁰Ar/³⁹Ar investigation of Middle Stone Age (MSA) obsidian artifacts (i.e. debitage pieces) for this purpose, as well as of potential geological obsidian sources from Ethiopia. With the present pilot study we demonstrate that ⁴⁰Ar/³⁹Ar geochronology represents a reliable and powerful tool for archaeological provenance studies complementary to the geochemical approach and more recently applied techniques like fission track counting or Mössbauer spectroscopy. Two independent sets of debitage and potential source rock samples were dated by the ⁴⁰Ar/³⁹Ar method. Debitage pieces from the Kulkuletti excavation site and obsidian samples from the nearby obsidian outcrop Worja (central Ethiopia) exhibit basically identical age ranges as well as similar Ca/K and Cl/K ratios, supporting the debitage/source rock relationship previously inferred on geochemical grounds. A second small set of geochemically characterized debitage samples from the Porc Epic cave and potential source rocks from an obsidian outcrop at Kone (Eastern Ethiopia) however have different ⁴⁰Ar/³⁹Ar ages and Ca/K and Cl/K ratios. These results contradict the previous conclusion about a debitage/source rock relationship of the Porc Epic and Kone samples made on the basis of geochemistry [A. Negash, M.S. Shackley, Archaeometry 48 (2006) 1]. Additional sampling at the Kone outcrop as well as of other obsidian occurrences in the greater area is needed to unambiguously pinpoint the origin of these obsidian tools.     

The Lower Acheulian site of Ambrona,Soria (Spain): ages derived from a combined ESR/U-series model

The Lower Paleolithic sites of Ambrona and Torralba (Soria, Spain) are often associated with each other because of their proximity although they do not represent the same morphostratigraphic unit. Systematic and extensive excavations were conducted at these sites by an American team during the 1960s and 1980s. Recently (1989–2000), a Spanish team has reactivated the research by initiating a new interdisciplinary project. In the central sector and west of the Ambrona site a stratigraphy has been established with six units from AS1 at the base to AS6 at the surface, corresponding to fluvial–lacustrine deposits in which abundant fauna associated with Acheulian artefacts were found. The most abundant species were elephant, horse, deer and aurochs. Other species like carnivores occur in small numbers only. The lithic assemblage is relatively sparse and consists of a few bifaces, choppers and several flake tools distributed throughout levels AS1 to AS5. The fauna and the lithic industry therefore document human presence at Ambrona during the Middle Pleistocene. In order to verify the presumed antiquity of the Ambrona deposits, horse teeth sampled in levels AS1, AS2 and AS6 were analysed using combined ESR/U-series (US) methods. The samples from the lower levels (AS1 and AS2) underwent a very recent uranium uptake as indicated by the U-series dates, ranging between 5 and 18 ka. In contrast, a more conventional postmortem uranium uptake was observed in the upper level samples (AS6) in the enamel and dentine tissues, while a light U-leaching was observed in the cementum. The combined ESR/U-series dates obtained on these samples suggest a minimum age of approximately 350 ka, contemporaneous of OSI 9 or the end of OSI 11, for the Ambrona site.     

Mass spectrometric U-series dating of Laibin hominid site in Guangxi, southern China

The Laibin hominid represents one of the rare finds of modern Homo sapiens in China, rare for its relative completeness and well-established stratigaphic provenance. This paper presents the results of mass spectrometric U-series dating of intercalated calcite samples from the Laibin site. The capping flowstone and the calcite vein, which sandwich the hominid fossil-containing deposits, date to 38.5 ± 1.0 and 44.0 ± 0.8 ka, setting respectively the minimum and maximum ages to the fossils. The second flowstone layer is 112.0 ± 1.4 ka old, indicating that the cultural sequence may possibly extend to somewhere between 44 and 112 ka. Securely dated Laibin finds should be of importance in reconstructing human physical and cultural evolution in the region.     

Archaeological Tree-Ring Dating at the Millennium

Tree-ring analysis provides chronological, environmental, and behavioral data to a wide variety of disciplines related to archaeology including architectural analysis, climatology, ecology, history, hydrology, resource economics, volcanology, and others. The pace of worldwide archaeological tree-ring research has accelerated in the last two decades, and significant contributions have recently been made in archaeological chronology and chronometry, paleoenvironmental reconstruction, and the study of human behavior in both the Old and New Worlds. This paper reviews a sample of recent contributions to tree-ring method, theory, and data, and makes some suggestions for future lines of research.     

Palaeomagnetic dating of fluid-flow events in dolomitized rocks along the Highland Boundary Fault, central Scotland

Palaeomagnetic and geochemical studies of Cambrian–Ordovician serpentinite in the Highland Border Complex (HBC), a tectonic terrane along the Highland Boundary Fault (HBF) in Scotland, indicate that the HBF was a conduit for fluids in the Carboniferous–Permian. The fluids caused dolomitization, silicification, and haematite authigenesis. Both red dolomitized serpentinite and relatively unaltered serpentinite were sampled at multiple localities. The unaltered serpentinite contains a poorly defined magnetization with westerly declinations that resides in magnetite and has a pole which plots well off the apparent polar wander path. Most specimens of the red dolomitized serpentinite contain a magnetization with southerly declinations and negative inclinations that resides in haematite. A regional fold test suggests that this magnetization post‐dates tilting and the pole positions for the different locations fall on the Carboniferous to Permian part of the apparent polar wander path. In some specimens of red dolomitized serpentinite, alternating field (AF) demagnetization prior to thermal treatment removes a component with a similar direction. Dolomitized basement rocks along the fault contain a similar although apparently slightly older magnetization. Fluid inclusion and geochemical studies indicate that the fluids were hydrothermal in origin (110–240°C) and had a range of sources. The Carboniferous–Permian magnetization in haematite is interpreted as a chemical remanent magnetization that formed when warm fluids moved along the fault zone and caused haematite authigenesis. The component removed by AF treatment is interpreted as a thermal resetting of primary magnetite by the fluids. The variability of the palaeomagnetic, fluid inclusion, and stable isotope results suggests that there were probably multiple flow events that caused the alteration. The origin of the fluids could be related to the intrusion of late Carboniferous dikes in central Scotland and/or to reactivation of the HBF in the Carboniferous–Permian.     

‘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.     

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.