scholarly journals Dating correlated microlayers in oxalate accretions from rock art shelters: New archives of paleoenvironments and human activity

2021 ◽  
Vol 7 (33) ◽  
pp. eabf3632
Author(s):  
Helen Green ◽  
Andrew Gleadow ◽  
Vladimir A. Levchenko ◽  
Damien Finch ◽  
Cecilia Myers ◽  
...  

Oxalate-rich mineral accretions, often found in rock shelters around the world, offer important opportunities for radiocarbon dating of associated rock art. Here, sample characterization and chemical pretreatment techniques are used to characterize the accretions, prescreen for evidence of open-system behavior, and address potential contamination. The results provide stratigraphically consistent sequences of radiocarbon dates in millimeter-scale laminated accretions, demonstrating their reliability for dating rock art, particularly symbolic markings commonly engraved into these relatively soft deposits. The age sequences are also consistent with correlations between distinctive patterns in the layer sequences visible in shelters up to 90 km apart in the Kimberley region of northwestern Australia, suggesting their synchronized formation is not entirely shelter specific but broadly controlled by variations in regional environmental conditions. Consequently, these accretions also offer potential as paleoenvironmental archives, with radiocarbon dating of layers in nine accretions indicating four, approximately synchronous growth intervals covering the past 43 ka.

Radiocarbon ◽  
2020 ◽  
pp. 1-8
Author(s):  
Alyssa M Tate ◽  
Brittany Hundman ◽  
Jonathan Heile

ABSTRACT Leather has been produced by a variety of methods throughout human history, providing researchers unique insight into multiple facets of social and economic life in the past. Archaeologically recovered leather is often fragile and poorly preserved, leading to the use of various conservation and restoration efforts that may include the application of fats, oils, or waxes. Such additives introduce exogenous carbon to the leather, contaminating the specimen. These contaminants, in addition to those accumulated during interment, must be removed through chemical pretreatment prior to radiocarbon (14C) dating to ensure accurate dating. DirectAMS utilizes organic solvents, acid-base-acid (ABA) and gelatinization for all leather samples. Collagen yield from leather samples is variable due to the method of production and the quality of preservation. However, evaluating the acid-soluble collagen fraction, when available, provides the most accurate 14C dates for leather samples. In instances where gelatinization does not yield sufficient material, the resulting acid-insoluble fraction may be dated. Here we examine the effectiveness of the combined organic solvent and ABA pretreatment with gelatinization for leather samples, as well as the suitability of the acid-insoluble fraction for 14C dating.


Radiocarbon ◽  
1983 ◽  
Vol 25 (2) ◽  
pp. 639-644 ◽  
Author(s):  
H T Waterbolk

In the past 30 years many hundreds of archaeologic samples have been dated by radiocarbon laboratories. Yet, one cannot say that 14C dating is fully integrated into archaeology. For many archaeologists, a 14C date is an outside expertise, for which they are grateful, when it provides the answer to an otherwise insoluble chronologic problem and when it falls within the expected time range. But if a 14C date contradicts other chronologic evidence, they often find the ‘solution’ inexplicable. Some archaeologists are so impressed by the new method, that they neglect the other evidence; others simply reject problematic 14C dates as archaeologically unacceptable. Frequently, excavation reports are provided with an appendix listing the relevant 14C dates with little or no discussion of their implication. It is rare, indeed, to see in archaeologic reports a careful weighing of the various types of chronologic evidence. Yet, this is precisely what the archaeologist is accustomed to do with the evidence from his traditional methods for building up a chronology: typology and stratigraphy. Why should he not be able to include radiocarbon dates in the same way in his considerations?


Antiquity ◽  
1961 ◽  
Vol 35 (140) ◽  
pp. 286-291 ◽  
Author(s):  
Geoffrey Bushnell

It is a commonplace of current archaeology that the publication of radiocarbon dates is revolutionizing our ideas of the past. Dr G. H. S. Bushnell, Curator of the Museum of Archaeology and Ethnology in the University of Cambridge, England, has already published in ANTIQUITY and elsewhere some of his views on the impact of radiocarbon dating on New World chronology. Here he studies the whole problem in detail. He adopts the useful convention of referring to a date already fully published in the Radiocarbon Supplement to the American Journal of Science simply by its laboratory designation and number {thus K-554 is reading no. 554 of the Copenhagen Laboratory), but in some cases, where the date is not fully published, he gives fuller information.


2021 ◽  
Author(s):  
Daniel James ◽  
Bruno David ◽  
Jean-Jacques Delannoy ◽  
Robert Gunn ◽  
Alexandria Hunt ◽  
...  

In 2011, we began researching the subsurface archaeology, geomorphology and rock art ofDalakngalarr 1, a moderately sized rock shelter on top of the central-western Arnhem Landplateau in Jawoyn Country. Here, four lines of evidence give relative or absolute ages for rockart:1. Archaeological excavations adjacent to a boulder that contains a painting of a red macropodreveal when that boulder attained its present position, so the red macropod must have beenpainted sometime afterwards.2. Paintings of axe/hoes with metal heads indicate that they were painted during the Europeancontact period. A nearby group of X-ray images are painted in comparable pigments,suggesting that they are contemporaneous with the axe/hoes.3. Geomorphological evidence suggests that parts of the site’s ceiling collapsed at datable timesin the past, indicating that the art on that roof must post-date the roof collapse.4. Direct accelerator mass spectrometry (AMS) radiocarbon dates on beeswax art.


Radiocarbon ◽  
1989 ◽  
Vol 31 (2) ◽  
pp. 121-144 ◽  
Author(s):  
Marshall Weisler

The importance of chronometric dating in archaeology cannot be overemphasized. Indeed, most chronologies developed throughout the world during the past three decades have depended on radiocarbon age determinations to provide a temporal framework for examining change over time in cultural sequences during the late Pleistocene and Holocene. With the advent of legislation in the mid-1960s designed to protect archaeological sites in the United States threatened by increased urban development or government sponsored projects, archaeological surveys and excavations were mandated as a means for preserving information otherwise destroyed. As a result, thousands of projects have contributed to a growing body of “gray literature,” ie, unpublished proprietary or manuscript reports with very limited circulation. Within these reports are hundreds, if not thousands, of 14C age determinations, most of which are not accessible in published form. One objective of this paper is to present all the 14C age determinations for the island of Moloka'i, Hawai'i as of December 1988, including 41 dates never before published with stratigraphic details.


Radiocarbon ◽  
2016 ◽  
Vol 58 (4) ◽  
pp. 893-904 ◽  
Author(s):  
Rachel J A Hopkins ◽  
Christophe Snoeck ◽  
Thomas F G Higham

AbstractThe influence of hydrochloric acid pretreatment on F14C and radiocarbon dates from dental enamel was investigated. Samples from modern equine incisors, a Roman cattle molar, and a Paleolithic woolly rhino molar were sampled and subsequently divided into five fractions. Each fraction was pretreated with a different acid solution, analyzed with Fourier transform infrared spectroscopy (FTIR), and accelerator mass spectrometry (AMS) 14C dated at the Oxford Radiocarbon Accelerator Unit (ORAU). When compared to a control date (e.g. dentine collagen), better results were observed when increased concentrations of hydrochloric acid solution were used in the chemical pretreatment. This pilot study suggests that decontamination of younger samples may be possible. However, for more fossilized samples with a high level of contamination (e.g. from the European Paleolithic), acid pretreatment under the conditions used in this study does not remove all contamination.


Radiocarbon ◽  
2013 ◽  
Vol 55 (3) ◽  
pp. 1432-1442 ◽  
Author(s):  
Yorgos Facorellis ◽  
Panagiotis Karkanas ◽  
Thomas Higham ◽  
Fiona Brock ◽  
Maria Ntinou ◽  
...  

Theopetra Cave is a unique prehistoric site for Greece, as the Middle and Upper Paleolithic, Mesolithic, and Neolithic periods are present here, bridging the Pleistocene with the Holocene. During the more than 20 yr of excavation campaigns, charcoal samples from hearths suitable for 14C dating were collected from all anthropogenic layers, including the Paleolithic ones. Most of the samples were initially dated using the ABA chemical pretreatment protocol in the Laboratory of Archaeometry of NCSR Demokritos, Greece, and the Radiocarbon Dating and Cosmogenic Isotopes Laboratory of the Weizmann Institute of Science, Israel. The 14C results, which were not always consistent versus depth, showed that the earliest limit of human presence is ∼50,000 yr BP, thus reaching the age limits of the 14C dating method. However, 10 TL-dated burnt flint specimens unearthed from the lower part of the Middle Paleolithic sequence of the cave gave ages ranging between ∼110 and 135 kyr ago. These results are in disagreement with the 14C dates, as they support a much later date for these layers. In order to clarify the situation further, charcoal samples originating from hearths were conventionally dated in the Laboratory of Archaeometry of NCSR Demokritos using the ABA pretreatment. Additionally, hand-picked charcoal fragments also underwent 14C dating by AMS in the Oxford Radiocarbon Accelerator Unit using the acid-base wet oxidation (ABOX-SC) pretreatment protocol. The 14C dates from the cave's Paleolithic layers obtained by both pretreatment protocols suggest a probable charcoal diagenesis affecting the 14C results of these very old samples. However, the dates obtained with ABOX-SC pretreatment are considered more reliable and in the younger stratigraphic part produced consistent results with the TL dating.


Antiquity ◽  
2001 ◽  
Vol 75 (290) ◽  
pp. 799-800
Author(s):  
Cornelia Kleinitz

Sub-Saharan West Africa has remained largely a blank space on the world rock-art map, in spite of a steady trickle of reports during the past century on pictograph and petroglyph sites in the West African sahel and savanna belts. It seems that the nature of the rock art reported, predominantly ‘geometric’ and saurian motifs, and ‘stick figures’, as well as its apparent recent age, formed little incentive for in-depth studies of rock art in this region. From sub-Saharan Mali, for example, only two sites have been published to a satisfactory standard (Huysecom 1990; Huysecom et al. 1996). The richness of the region in rock art, as indicated by several authors (e.g. Griaule 1938; Huysecom & Mayor 1991/92; Togola et al. 1995), has been confirmed by on-going research on rock art in the Boucle du Baoulé region (map, FIGURE 5) in the southwest of the country (Kleinitz 2000). In three field seasons, 14 known and 38 newly identified rock-shelters and open-air sites with pictographs and peboglyphs have been recorded.


1990 ◽  
Vol 34 (1) ◽  
pp. 111-120 ◽  
Author(s):  
Thomas W. Stafford ◽  
P.E. Hare ◽  
Lloyd Currie ◽  
A. J. T. Jull ◽  
Douglas Donahue

AbstractAccelerator mass spectrometry (AMS) radiocarbon dates fail to provide conclusive evidence that all New World human fossils are younger than approximately 11,000 yr. Because fossil bones vary widely in preservation, their radiocarbon dates are not equally accurate. Molecular-level radiocarbon dating, which used individual amino acids to assess fossil diagenesis, revealed that dates on known-age, noncollagenous bone were underestimated by at least 2000 to 9000 yr. The significance is that >11,000-yr-old fossil bones with poor preservation would yield Holocene and not Pleistocene radiocarbon ages, regardless of what chemical pretreatment or 14C counting method was used. Irreplaceable evidence for Pleistocene-age fossils in the New World could be lost if the diagenesis of fossil bones is not evaluated before the bones are radiocarbon dated. In contrast, radiocarbon ages for collagenous fossils can be determined more accurately if 14C is measured in several individual amino acids that are isolated from collagenous bone protein. Molecular-level radiocarbon dating will greatly improve not only the accuracy of chronologies for human migrations and animal extinctions, but of all late Quaternary chronologies that are based upon the 14C dating of fossil proteins.


Author(s):  
Fiona Petchey

Radiocarbon dating has had a significant impact on rock art research, but an initial enthusiasm for this dating method by archaeologists has been replaced by a degree of scepticism. Radiocarbon dates undertaken directly on rock art or on associated mineral crusts have often reinforced such scepticism, in part because organic carbon-based materials are present in small quantities and their composition is of such variable composition that the technique is stretched to its limits. For the researcher planning to obtain radiocarbon dates, it is essential to have an understanding of the dating options available, limitations of the technique, the potential impact of their own bias, and the value of a dating programme that is fully integrated within a larger project. This chapter outlines the various materials and methods used to radiocarbon date rock art. It includes some recent examples and highlights some advances as well as shortfalls in the dating of rock art.


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