• Response to Moss et al. “An Early Holocene/Late Pleistocene Archaeological Site on the Oregon Coast? Comments on Hall et al. (2005)”

      Davis, Loren G.; Hall, Roberta A.; Willis, Samuel C. (Department of Geosciences, The University of Arizona, 2006-01-01)
      Moss et al. (2006) provided comments and criticisms of our recent paper in this journal (Hall et al. 2005). We can appreciate the need for promoting vigorous dialogue among those interested in the research of early sites along the New World Pacific Margin and thus welcome their intervention; however, we are compelled to respond because they raise several points that require clarification and introduce a critical error that must be corrected.
    • Seawater Radiocarbon Evolution in the Gulf of Alaska: 2002 Observations

      Guilderson, Thomas P.; Roark, E. Brendan; Quay, Paul D.; Flood Page, Sarah; Moy, Christopher (Department of Geosciences, The University of Arizona, 2006-01-01)
      Oceanic uptake and transport of bomb radiocarbon as 14CO2 created by atmospheric nuclear weapons testing in the 1950s and 1960s has been a useful diagnostic for determining the carbon transfer between the ocean and atmosphere. In addition, the distribution of 14C in the ocean can be used as a tracer of oceanic circulation. Results obtained on samples collected in the Gulf of Alaska in the summer of 2002 provide a direct comparison with results in the 1970s during GEOSECS and in the early 1990s during WOCE. The open gyre values are 20-40 lower than those documented in 1991 and 1993 (WOCE), although the general trends as a function of latitude are reproduced. Surface values are still significantly higher than pre-bomb levels (~-105 or lower). In the central gyre, we observe ∆14C values that are lower in comparison to GEOSECS (stn 218) and WOCE P16/P17 to a density of ~26.8 sigma-t. This observation is consistent with the overall decrease in surface ∆14C values and reflects the erosion of the bomb-14C transient. We propose that erosion of the bomb-14C transient is accomplished by entrainment of low-14C water via vertical exchange within the Gulf of Alaska and replenishment of surface and subthermocline waters with waters derived from the far northwest Pacific.
    • Seoul National University Accelerator Mass Spectrometry (SNU-AMS) Radiocarbon Date List I

      Kim, J. C.; Youn, M. Y.; Kim, I. C.; Park, J. H.; Song, Y. M.; Kang, J.; Cheoun, M. K. (Department of Geosciences, The University of Arizona, 2006-01-01)
      The accelerator mass spectrometry facility at Seoul National University (SNU-AMS) began functioning in December 1998 and was first reported at the Vienna AMS conference in October 1999 and at the 17th International Radiocarbon Conference in Israel in June 2000. At the Vienna conference, we reported our accelerator system (Kim et al. 2000) and details of the basic sample preparation system (Lee et al. 2000), such as the combustion line to produce CO2 ; the catalytic reduction line for the graphitization of CO2 ; and the pretreatment procedures for wood, charcoal, and peat samples. The recent progress of the AMS facility (Kim et al. 2001) and the extension of the sample pretreatment system to iron and bone samples were reported at the 17th International Radiocarbon Conference (Cheoun et al. 2001). In the meantime, extensive testing of accuracy and reproducibility has been carried out, and ~1000 unknown archaeological and geological samples have been measured every year. In this report, the archaeological, geological, and environmental data carried out in 1999 are presented in terms of yr BP.
    • Seoul National University Accelerator Mass Spectrometry (SNU-AMS) Radiocarbon Date List II

      Kim, J. C.; Youn, M. Y.; Kim, I. C.; Park, J. H.; Song, Y. M.; Kang, J. (Department of Geosciences, The University of Arizona, 2006-01-01)
      The accelerator mass spectrometry facility at Seoul National University (SNU-AMS) began functioning in December 1998 and was first reported at the Vienna AMS conference in October 1999 and at the 17th Radiocarbon Conference in Israel in June 2000. At the Vienna conference, we reported our accelerator system (Kim et al. 2000) and the basic sample preparation system (Lee et al. 2000), including the combustion line to produce CO2 ; the catalytic reduction line for the graphitization of CO2 ; and also pretreatment procedures for wood, charcoal, and peat samples. Recent progress of the AMS facility (Kim et al. 2001) and extension of the sample pretreatment system to iron and bone samples were reported at the 17th Radiocarbon Conference (Cheoun et al. 2001). In the meantime, extensive testing of accuracy and reproducibility has been carried out, and ~1000 unknown archaeological and geological samples have been measured every year. A report of data carried out in 1999 is presented by Kim et al. (this issue). In this report, the archaeological, geological, and environmental data carried out in 2000 are presented in terms of yr BP.
    • Society Islands (Central Eastern Polynesia) Chronology: 11 Radiocarbon Dates for the Late Prehistoric Expansion and Proto-Historic Periods in the Opunohu Valley, Moorea

      Kahn, Jennifer G. (Department of Geosciences, The University of Arizona, 2006-01-01)
      The chronology of residential site construction and occupation in the upper reaches of the Opunohu Valley, Moorea, Central Eastern Polynesia, has been debated over the last 15 yr. This paper reports a suite of 11 radiocarbon age determinations from excavations at 5 house sites and a simple temple structure (marae). Direct accelerator mass spectrometry (AMS) dating of wood charcoal identified to short-lived taxa confirms site construction and occupation during the mid-15th to 17th centuries, supporting that maximal population density was in the centuries immediately prior to European contact. The study demonstrates that targeted dating of multiple structures within residential complexes allows for multiple phases of site construction and use to be discriminated. These data are critical for adequately assessing site contemporaneity and the development, maintenance, and expansion of residential groups and their house clusters through time.
    • Southern Palestinian Chronology: Two Radiocarbon Dates for the Early Bronze Age at Tell El-Hesi (Israel)

      Anderson, Roger W. (Department of Geosciences, The University of Arizona, 2006-01-01)
      Several articles reporting radiocarbon dates of Early Bronze Age (EB) material from excavations in the southern Levant have been published over the last 30 yr. The excavations conducted at Tell el-Hesi have produced material from which 2 additional 14C dates have been extracted to date. The 2 samples confirm the EB dating of Field VI material and suggest EB III settlement at Hesi might be earlier than previously reported based on pottery typology.
    • Testing the Limits: Radiocarbon Dating and the End of the Late Bronze Age

      Hagens, Graham (Department of Geosciences, The University of Arizona, 2006-01-01)
      Archaeometry is becoming an increasingly important tool in chronological research related to events in the Ancient Near East during the 2nd millennium BCE. This paper is a review of recently published radiometric results in an attempt to establish the probable dating range for one particular event that occurred during the last quarter of that millennium, the end of the Late Bronze Age. The conclusion is that in spite of significant improvements in methodology in recent years, the quantity and quality of radiocarbon data are still insufficient to define the range of that date to much better than a century. It is concluded that the most likely date of the Late Bronze/Iron Age transition (here defined by the arrival of Mycenaean LH IIIC:1b pottery in the Levant) is somewhere in the 8-decade range between ~1170 to 1100 BCE. A comparative study of archaeological and historical evidence would appear to favor the lower value.
    • The 3MV Multi-Element AMS in Xi'an, China: Unique Features and Preliminary Tests

      Zhou, Weijian; Zhao, Xiaolei; Xuefeng, Lu; Lin, Liu; Zhengkun, Wu; Peng, Cheng; Wengnian, Zhao; Chunhai, Huang (Department of Geosciences, The University of Arizona, 2006-01-01)
      A 3MV multi-element accelerator mass spectrometer (AMS) has been installed in Xian, China, and preliminary tests have been completed. The results of both background and precision tests for 4 nuclides are 3.1 x 10^-16, 0.2% (14C); 1.8 x 10^-14, 1.4% (10Be); 2.3 x 10^-15, 1.14% (26Al); and 2.0 x 10^-14, 1.75% (129I). The unique features of this facility are the newly developed ion source accepting solid and CO2 samples; the specially designed low-energy injector, including a beam blanking unit and Q-snout; the acceleration tube structure with the combined magnetic and electrostatic suppression; and the function of the slit stabilization in the post-acceleration system. These features are discussed in terms of the end-users point of view.