Application of U/Th and 40Ar/39Ar Dating to Orgnac 3, a Late Acheulean and Early Middle Palaeolithic Site in Ardèche, France

• DOI: 10.1371/journal.pone.0082394
• Publication Date: 2013-12-05T21:53:10Z
• Authors: Véronique Michel; Guanjun Shen; Chuan-Chou Shen; Chung-Che Wu; Chrystèle Vérati; Sylvain Gallet; Marie-Hélène Moncel; Jean Combier; Samir Khatib; Michel Manetti
• Keywords: Speleothem; Acheulean; Stalagmite; Marine isotope stage; Radiometric dating; Sequence (biology)

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 level 4b the middle sequence, became predominant upper horizons, was best represented uppermost 1, making one oldest examples technology. In our study, fourteen speleothem samples from levels 7, 6 5b, were U/Th-dated. Four pure calcite PL1 (levels 6) yield ages between 265 ± 4 (PL1-3) 312 15 (PL1-6) thousand years ago (ka). Three top second stalagmite, PL2, dates ranging 288 10 ka (PL2-1) 298 17 (PL2-3). base PL2 (level 7) much younger U/Th 267 283 ka. These show that speleothems are contemporaneous formed during marine isotope stage (MIS) 9 MIS 8. Volcanic minerals 2, dated by (40)Ar/(39)Ar method, giving weighted mean 302.9 2.5 (2σ) an inverse isochron age 5.9 (2σ). Both volcanic sanidines relatively dense cave calcites known be well established. The first parallel application two geochronometers 3 yields generally consistent results, which point reliability methods. difference their results is discussed.