• Table of Contents

      Department of Geosciences, The University of Arizona, 2009-01-01
    • Temporal Change of Radiocarbon Reservoir Effect in Sugan Lake, Northwest China during the Late Holocene

      Zhou, Ai-feng; Chen, Fa-hu; Wang, Zong-li; Yang, Mei-lin; Qiang, Ming-rui; Zhang, Jia-wu (Department of Geosciences, The University of Arizona, 2009-01-01)
      Many lacustrine chronology records suffer from radiocarbon reservoir effects. A continuous, accurate varve chronology, in conjunction with accelerator mass spectrometry (AMS) 14C dating, was used to determine the age of lacustrine sediment and to quantify the past 14C reservoir effect in Sugan Lake (China). Reservoir age varied from 4340 to 2590 yr due to 14C-depleted water in the late Holocene. However, during the Little Ice Age (LIA), 14C reservoir age was relatively stable. According to this study, 14C reservoir age in the late Holocene may be driven by hydrological and climatic changes of this period. Therefore, special caution should be paid to the correction of the 14C reservoir effect by a unique 14C reservoir age in paleoclimatic and paleolimnological study of northwest China.
    • The Formation of Deluvial and Alluvial Cones as a Consequence of Human Settlement on a Loess Plateau: An Example from the Chroberz Area (Poland)

      Szwarczewski, Piotr (Department of Geosciences, The University of Arizona, 2009-01-01)
      The area of Chroberz (southern Poland) poses questions of an interdisciplinary character comprising geomorphologic, sedimentation, and archaeological-historical problems. The main aim of this study was to identify the geomorphologic response to changes in the natural environment that took place in the area of the loess plateau (and its close vicinity) as a result of its settlement by man and of climate change. Periods of particularly intense human activity (land-use changes, deforestation, and agriculture) were recorded as changes in the type of sedimentation, i.e. organic sedimentation substituted for mineral one; it was extremely intensive during the Neolithic Age, Iron Age, and Early Middle Ages. The conducted fieldwork research, analysis of available archaeological materials, and radiocarbon dating results show that there is a direct connection between human economic activity in primeval and historic times and between soil erosion and accumulation of colluvial/alluvial fans in the surroundings of the locality of Chroberz. 14C dates documenting the age of colluvial sediment formation show that individual areas of the upland were settled by humans asynchronously. On the basis of a low facial variability, or, occasionally, even homogeneity, of individual colluvia (from soil erosion) and their considerable thickness, it can be concluded that the land was in constant use or that the intervals with no human activity were relatively short. The progressing human impact process is visible both in the form progradation recorded as the changes in 14C ages (e.g. from 1440 +/- 100 to 780 +/- 80 BP) and in textural (e.g. chemical) features of sediments of which the examined fans are composed.
    • The Impact of Cremated Bone Dating on the Archaeological Chronology of the Low Countries

      De Mulder, Guy; Van Strydonck, Mark; Boudin, Mathieu (Department of Geosciences, The University of Arizona, 2009-01-01)
      Since the publication of the first article (Lanting and van der Plicht 2001/2002) about the possibilities of dating cremated bones, the number of dated cremation remains has grown exponentially. The success of this dating technique lies in the fact that an absolute date now can be attributed to archaeological phenomena that previously were only datable indirectly. When archaeological artifacts where present, the cremation burials were dated based on the typology of ceramics and metals. An absolute date could be attributed if charcoal from the pyre were present. Unfortunately, these items were not omnipresent at the burial sites. Consequently, a complete site was dated by means of the few datable burials present. This implies that the internal chronology of the site could not be studied. Furthermore, the typochronology of the ceramics and the metals remains questionable. A series of dating projects on urnfield cemeteries in the Low Countries (northern France, Belgium, and the Netherlands) have shown that the classical chronology of these sites must be revised.
    • The Minoan Santorini Eruption and Tsunami Deposits in Palaikastro (Crete): Dating by Geology, Archaeology, 14C, and Egyptian Chronology

      Bruins, Hendrik J.; van der Plicht, Johannes; MacGillivray, J. Alexander (Department of Geosciences, The University of Arizona, 2009-01-01)
      Deposits from the Minoan Santorini (Thera) eruption in the eastern Mediterranean region constitute the most important regional stratigraphic marker in the chronological perplexity of the 2nd millennium BCE. Extensive tsunami deposits were discovered in Crete at the Minoan archaeological site of Palaikastro, containing reworked volcanic Santorini ash. Hence, airborne deposition of volcanic ash, probably during the 1st (Plinian) eruption phase, preceded the tsunami, which was apparently generated during the 3rd or 4th phase of the eruption, based on evidence from Thera. Average radiocarbon dates (uncalibrated) of animal bones in the Palaikastro tsunami deposits along the coast (3350 +/- 25 BP) and at the inland archaeological site (3352 +/- 23 BP) are astoundingly similar to the average 14C date for the Minoan Santorini eruption at Akrotiri on Thera (3350 +/- 10 BP). The wiggle-matched 14C date of the eruption in calendar years is 1627-1600 cal BCE. Late Minoan IA pottery is the youngest element in the Palaikastro tsunami deposits, fitting with the LM IA archaeological date for the Santorini eruption, conventionally linked at ~1500 BCE with Dynasty XVIII of the historical Egyptian chronology. The reasons for the discrepancy of 100-150 yr between 14C dating and Egyptian chronology for part of the 2nd millennium BCE are unknown. 14C dates from Tell el-Dabca in the eastern Nile Delta show that the 14C age of the Santorini eruption matches with 14C results from 18th Dynasty strata C3 and C2, thereby confirming grosso modo the conventional archaeo-historical correlations between the Aegean and Egypt. We propose that a dual dating system is used in parallel: (1) archaeological material-cultural correlations linked to Egyptian chronology; (2) 14C dating. Mixing of dates from the 2 systems may lead to erroneous archaeological and historical correlations. A 'calibration curve' should be established between Egyptian chronology and 14C dating for the 2nd millennium BCE, which may also assist to resolve the cause of the discrepancy.
    • The Spread of the Neolithic in the South East European Plain: Radiocarbon Chronology, Subsistence, and Environment

      Dolukhanov, Pavel M.; Shukurov, Anvar; Davison, Kate; Sarson, Graeme; Gerasimenko, Natalia P.; Pashkevich, Galina A.; Vybornov, Aleksandr A.; Kovalyukh, Vikolai N.; Skripkin, V. V.; Zaitseva, Ganna I.; et al. (Department of Geosciences, The University of Arizona, 2009-01-01)
      Newly available radiocarbon dates show the early signs of pottery-making in the North Caspian area, the Middle-Lower Volga, and the Lower Don at 8-7 kyr cal BC. Stable settlements, as indicated by "coeval subsamples," are recognized in the Middle-Lower Volga (Yelshanian) at 6.8 kyr cal BC and the Caspian Lowland at about 6 kyr cal BC. The ages of the Strumel-Gostyatin, Surskian, and Bug-Dniesterian sites are in the range of 6.6-4.5 kyr BC, overlapping with early farming entities (Starčevo-Krs-Criş and Linear Pottery), whose influence is perceptible in archaeological materials. Likewise, the 14C-dated pollen data show that the spread of early pottery-making coincided with increased precipitation throughout the forest-steppe area.
    • Ultrafiltration: Boon or Bane?

      Hüls, C. M.; Grootes, P. M.; Nadeau, M.-J. (Department of Geosciences, The University of Arizona, 2009-01-01)
      Ultrafiltration of bone collagen, dissolved as gelatin (M ~100,000 D), has received considerable attention as a means to remove small contaminants and thus produce more reliable dates (Brown et al. 1988; Bronk Ramsey et al. 2004; Higham et al. 2006; Mellars 2006). However, comparative dating studies have raised the question whether this cleaning step itself may introduce contamination with carbon from the filters used (Bronk Ramsey et al. 2004; Brock et al. 2007; Hüls et al. 2007). Here, we present results of further ultrafiltration experiments with modern and fossil collagen samples using Vivaspin 20 and Vivaspin 15R ultrafilters. Evidently, the Vivaspin 20 (VS 20) ultrafilter with a polyethersulfone (PES) membrane retains more material in the 30 kD fraction than the Vivaspin 15R (VS 15R) filter with a regenerated cellulose membrane (Hydrosat), which may be related to increased retention of proteins due to suboptimal electrostatic conditions during ultrafiltration with the PES membrane. In addition, this filter type shows clear evidence for contamination with fossil carbon, presumably from membrane fibers, in the 30 kD fraction. Radiocarbon measurements on ultrafiltrated fossil collagen seem to indicate small contributions of modern carbon via glycerin left on and within the filter membranes of both types. Although SEM pictures show film remnants on the fibrous filter structure of cleaned filter membranes, EDX analysis on the VS 20 membrane to not support the assumption this may be glycerin. Our observations indicate the risks and benefits of the use of ultrafiltration in cleaning collagen samples for 14C dating need to be further quantified, especially for the cleaning of fossil bone collagen of good quality samples.
    • Wiggle-Matching Using Known-Age Pine from Jermyn Street, London

      Tyers, Cathy; Sidell, Jane; van der Plicht, Johannes; Marshall, Peter; Cook, Gordon; Bronk Ramsey, Christopher; Bayliss, Alex (Department of Geosciences, The University of Arizona, 2009-01-01)
      A slice of pine from the period covered by single-year calibration data (Stuiver 1993) was selected to serve as part of the quality assurance procedures of the English Heritage radiocarbon dating program, following successful wiggle-matching of 14C measurements from structural 15th century English oak timbers (Hamilton et al. 2007). The timber selected was a roofing element from a house on Jermyn Street, central London, demonstrated by dendrochronology to have been felled in AD 1670. Eighteen single-ring samples were dated by the 14C laboratories at Groningen, Oxford, and SUERC: each laboratory was sent a random selection of 6 samples. This approach was intended to mimic the mix of samples and relative ages incorporated into Bayesian chronological models during routine project research. This paper presents the results of this study.