title: Application of U/Th and 40Ar/39Ar dating to Orgnac 3, a Late Acheulean and Early Middle Palaeolithic site in Ardèche, France.
abstract: Refined radio-isotopic dating techniques have been applied to Orgnac 3, a Late Acheulean and Early Middle Palaeolithic site in France. Evidence of Levallois core technology appeared in level 4b in the middle of the sequence, became predominant in the upper horizons, and was best represented in uppermost level 1, making the site one of the oldest examples of Levallois technology. In our dating study, fourteen speleothem samples from levels 7, 6 and 5b, were U/Th-dated. Four pure calcite samples from the speleothem PL1 (levels 5b, 6) yield ages between 265 ± 4 (PL1-3) and 312 ± 15 (PL1-6) thousand years ago (ka). Three samples from the top of a second stalagmite, PL2, yield dates ranging from 288 ± 10 ka (PL2-1) to 298 ± 17 ka (PL2-3). Three samples from the base of PL2 (level 7) yield much younger U/Th dates between 267 and 283 ka. These dates show that the speleothems PL1 and PL2 are contemporaneous and formed during marine isotope stage (MIS) 9 and MIS 8. Volcanic minerals in level 2, the upper sequence, were dated by the (40)Ar/(39)Ar method, giving a weighted mean of 302.9 ± 2.5 ka (2σ) and an inverse isochron age of 302.9 ± 5.9 ka (2σ). Both (40)Ar/(39)Ar dating of volcanic sanidines and U/Th dating of relatively pure and dense cave calcites are known to be well established. The first parallel application of the two geochronometers to Orgnac 3 yields generally consistent results, which point to the reliability of the two methods. The difference between their age results is discussed.
authors.affiliation: Université Nice Sophia Antipolis, Campus Saint-Jean-d'Angély, SJA3 - CEPAM- UMR 7264 CNRS, Nice Cedex 4, France ; Géoazur, UMR7329, UNS-CNRS-IRD-OCA, Valbonne, France.
authors.forename: Véronique
authors.initials: V
authors.lastname: Michel
authors.affiliation: College of Geographical Sciences, Nanjing Normal University, Nanjing, China.
authors.forename: Guanjun
authors.initials: G
authors.lastname: Shen
authors.affiliation: High-precision Mass Spectrometry and Environment Change Laboratory (HISPEC), Department of Geoscience, National Taiwan University N°1, Taipei, Taiwan ROC.
authors.forename: Chuan-Chou
authors.initials: CC
authors.lastname: Shen
authors.affiliation: High-precision Mass Spectrometry and Environment Change Laboratory (HISPEC), Department of Geoscience, National Taiwan University N°1, Taipei, Taiwan ROC.
authors.forename: Chung-Che
authors.initials: CC
authors.lastname: Wu
authors.affiliation: Géoazur, UMR7329, UNS-CNRS-IRD-OCA, Valbonne, France.
authors.forename: Chrystèle
authors.initials: C
authors.lastname: Vérati
authors.affiliation: Géoazur, UMR7329, UNS-CNRS-IRD-OCA, Valbonne, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Gallet
authors.affiliation: Département de Préhistoire, UMR 7194, MNHN, IPH, Paris, France.
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Moncel
authors.affiliation: CNRS, Macon, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Combier
authors.affiliation: Laboratoire Départemental de Préhistoire du Lazaret, Nice, France.
authors.forename: Samir
authors.initials: S
authors.lastname: Khatib
authors.affiliation: Université Nice Sophia Antipolis, Département Terre-Environnement-Espace, Parc Valrose, Nice Cedex 2, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Manetti
mesh_terms: D000818:Animals; D001106:Archaeology; D001128:Argon / Q000737:chemistry*; D005580:Fossils; D005602:France; D008903:Minerals / Q000737:chemistry; D010163:Paleontology; D011868:Radioisotopes; D055110:Radiometric Dating / Q000379:methods*; D013910:Thorium / Q000737:chemistry*; D013997:Time Factors; D014501:Uranium / Q000737:chemistry*
chemical_list: D008903:Minerals; D011868:Radioisotopes; D014501:Uranium; D013910:Thorium; D001128:Argon