Methodological approaches to determining the marine radiocarbon reservoir effect

The marine radiocarbon reservoir effect is an offset in 14C age between contemporaneous organisms from the terrestrial environment and organisms that derive their carbon from the marine environment. Quantification of this effect is of crucial importance for correct calibration of the <sup>14</sup>C ages of marine-influenced samples to the calendrical timescale. This is fundamental to the construction of archaeological and palaeoenvironmental chronologies when such samples are employed in <sup>14</sup>C analysis. Quantitative measurements of temporal variations in regional marine reservoir ages also have the potential to be used as a measure of process changes within Earth surface systems, due to their link with climatic and oceanic changes. The various approaches to quantification of the marine radiocarbon reservoir effect are assessed, focusing particularly on the North Atlantic Ocean. Currently, the global average marine reservoir age of surface waters, R(t), is c. 400 radiocarbon years; however, regional values deviate from this as a function of climate and oceanic circulation systems. These local deviations from R(t) are expressed as +R values. Hence, polar waters exhibit greater reservoir ages (δR = c. +400 to +800 <sup>14</sup>C y) than equatorial waters (δR = c. 0 <sup>14</sup>C y). Observed temporal variations in δR appear to reflect climatic and oceanographic changes. We assess three approaches to quantification of marine reservoir effects using known age samples (from museum collections), tephra isochrones (present onshore/offshore) and paired marine/terrestrial samples (from the same context in, for example, archaeological sites). The strengths and limitations of these approaches are evaluated using examples from the North Atlantic region. It is proposed that, with a suitable protocol, accelerator mass spectrometry (AMS) measurements on paired, short-lived, single entity marine and terrestrial samples from archaeological deposits is the most promising approach to constraining changes over at least the last 5 ky BP

Radiocarbon Dating of the Architectural Parts of the Middle Byzantine Monastery of Hosios Loukas, Boeotia, Greece

The Monastery of Hosios Loukas is situated at an altitude of 430 m (38°23′43.12′′N, 22°44′48.22′′E) in the western foothills of Mount Helikon, near the village of Steiri, Boeotia, Greece. It is one of the most important monuments of Middle Byzantine art and architecture and has been recognized by UNESCO as a World Heritage Site. Information varies concerning the construction date of the magnificent church to house the Hosios Loukas relics. Moreover, little is known about the time when the rest of the monastic complex was built. This paper aims to shed light on these chronological questions. For this purpose, 15 wood samples, originating from the outermost rings of the wooden timber preserved from the initial scaffolding of the church and its four supporting buttresses and another two from the wooden gate of the monastery, were radiocarbon (14C) dated using the conventional gas-counting technique. Our results show that the church was built in the beginning of the 11th century. The four buttresses were built in at least two phases, during the 15th through 19th centuries, and the monastery gate may be also attributed to the 19th century. © 2017 by the Arizona Board of Regents on behalf of the University of Arizona

Radiocarbon Dating of the Amphipolis Bridge in Northern Greece, Maintained and Functioned for 2500 Years

The remains of a wooden construction, recovered in the 1970s at the northwest sector of the walls of the ancient city of Amphipolis (northern Greece), have been recognized as foundation remains of a wooden bridge described by Thucydides in his description of the events that took place at Amphipolis in 424-422 BC, during the Peloponnesian War. Frequent repairs in the Roman, Byzantine, and even Ottoman periods are very probable. In the last 10 yr, conservation has been done to enhance this unique monument. This work involves systematic investigation with radiocarbon dating of all the verified or suspected phases of this wooden bridge. The dating results reveal the beginning of construction most probably in the Archaic period and confirm beyond a doubt that the major construction phase took place in Classical times. Successive phases, related to repairs rather than to major reconstructions, have been detected during the Hellenistic, Roman, Early Christian, and Byzantine periods as well as the Ottoman era. The combined archaeometric and archaeological evidence leads to the remarkable conclusion that this bridge was functioning for about 2500 yr.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Neolithic thessaly: Radiocarbon dated periods and phases

Thessaly in Central Greece is famous for settlement mounds (magoules) that were already partly formed in the Early Neolithic period. Some of these long-lived sites grew to many metres in height during the subsequent Middle, Late and Final Neolithic periods, and were also inhabited in the Bronze Age. Such magoules served as the backbone for defining relative chronological schemes. However, their absolute dating is still a topic of debate: due to a lack of well-defined sequences, different chronological schemes have been proposed. New radiocarbon dates obtained in the last few years allow a better understanding of the duration not only of the main Neolithic periods, but also of the different phases and sub-phases

The Canal of Xerxes: investigations in 1993-1994

No abstract available

Palaeoenvironments and site formation processes at the Neolithic lakeside settlement of Dispilio, Kastoria, Northern Greece

Dispilio is a lakeside settlement by the Orestias Lake, Kastoria, northern Greece. The site was inhabited from the Middle Neolithic to the Chalcolithic, with some surface evidence of Bronze Age occupation. Microfacies analysis of the sediments, supported by a suite of environmental indices, has provided detailed paleoenvironmental data and elucidated the main processes involved in the formation of the site and its history of occupation. The settlement was established on the lakeshore, on a shallow sand ridge and a shore marsh. Initially, houses were built on raised platforms above the water. After a major conflagration, a range of depositional microenvironments were established that caused local changes in the sedimentation rate. Therefore, some areas quickly emerged and became dry land, while some others continued to be flooded as part of the transitional supra-littoral environment. On the dry land, houses were built directly on the ground, whereas in the transitional areas houses continued to be built on raised platforms. Thus, gradually, a mound was formed and further shaped by subsequent lake-level fluctuations. One of the lake-level rises is tentatively related to the abandonment of the mound in the Chalcolithic and the development of a hardpan on its surface. There is also evidence of later occupation during the Bronze Age in the form of a few, mostly surface, archaeological remains. © 2010 Wiley Periodicals, Inc

The Canal of Xerxes: investigations in 1993-1994

No abstract available