• Wiggle-Match Dating of Wooden Samples from Iron Age Sites in Northern Italy

      Quarta, G.; Pezzo, M. I.; Marconi, S.; Tecchiati, U.; D'Elia, M.; Calcagnile, L. (Department of Geosciences, The University of Arizona, 2010-01-01)
      Archaeological excavations carried out at the sites of Laion/Lajen (Bolzano/Bozen) and Stufles-Oberegger (Bressanone/Brixen) in northern Italy uncovered well-preserved wooden samples in cultural layers archaeologically dated to the Iron Age. From the 2 sites, different wooden samples were recovered that were well preserved enough to allow clear identification of the tree species and of the ring structure. Among the different wooden samples, 2 were selected for radiocarbon analyses: from Laion/Lajen, a beam with an unbroken sequence of 158 rings; from Stufles-Oberegger, a combusted trunk with a sequence of 217 rings. Both samples were identified as Larix decidua species. From each sequence, single rings were selected and submitted for accelerator mass spectrometry (AMS) 14C dating analysis at CEDAD. Conventional 14C ages were then calibrated to calendar ages using the IntCal04 atmospheric data set, while the statistical constraints resulting from the defined ring sequence were used to develop a wiggle-matching approach by making use of the Bayesian analysis functions available in OxCal. The obtained results are an important contribution in refining the chronology of the studied sites.
    • ZAGRADA—The New Zagreb Radiocarbon Database

      Porter, Antun; Obelić, Bogomil; Krajcar Bronić, Ines (Department of Geosciences, The University of Arizona, 2010-01-01)
      After introducing the liquid scintillation counting (LSC) method and graphite target preparation for accelerator mass spectrometry (AMS) measurements in the Zagreb Radiocarbon Laboratory, the existing database software designed only for gas proportional counting (GPC) (using a DOS operating system) could not satisfy the requirements for parallel conduction of several techniques. This has been enabled recently by the development of the new relational database ZAGRADA, which--using SQL scripts and constraints defined by primary and foreign keys--enforces high data integrity and provides better performances in data filtering and sorting. The structural scheme of this database conceptually comprises 4 basic modules with data on the samples, chemical pretreatment and preparation, measurements and data on the final results. A user-friendly graphical user interface has been designed to perform various actions and data manipulation to the database. The implementation of a new database for 14C samples has significant contribution to scientific research performed in the Radiocarbon and Tritium Laboratory and to quality assurance and quality control, and will enable better and easier communication with customers.