Located in Southern Italy, the Early Palaeolithic site of Isernia la Pineta has provided numerous palaeontological remains and artefacts in well-defined fluvio-lacustrine sequence. The normal magnetization of the main archaeological layer t3a and (39)Ar/(40)Ar date of 610 +/- 10 (2 sigma) ka, obtained from the immediately overlaying geological level, put the Isernia assemblage in the first part of the Middle Pleistocene. Previous ESR/U-series analyses of Isernia fossil teeth have displayed both recent U-uptake and severe underestimation of the ESR/U-series dates in comparison with the (39)Ar/(40)Ar age. In order to identify the cause of this age underestimation, new analyses were realized in the present study on four bovid teeth directly recovered from the archaeological surface t3a. The ESR/U-series dates obtained were once again strongly underestimated, with an error weighted mean age of 435 +/- 24 (1 sigma) ka. These too young dates could be associated to a change of the environmental gamma-dose rate during the geological history of the Isernia site, related to the revealed recent U-uptake into the palaeontological remains of the archaeological level. If we consider that this dose rate change was coeval with a wet interglacial period and taking the (39)Ar/(40)Ar age as geochronological reference, simulations with two dose rate steps indicate that this change could be correlated with marine isotopic stage 7 (MIS 7). (C) 2011 Elsevier Ltd. All rights reserved.
New ESR/U-series data for the early Middle Pleistocene site of Isernia la Pineta, Italy.
MINELLI, Antonella;
2011-01-01
Abstract
Located in Southern Italy, the Early Palaeolithic site of Isernia la Pineta has provided numerous palaeontological remains and artefacts in well-defined fluvio-lacustrine sequence. The normal magnetization of the main archaeological layer t3a and (39)Ar/(40)Ar date of 610 +/- 10 (2 sigma) ka, obtained from the immediately overlaying geological level, put the Isernia assemblage in the first part of the Middle Pleistocene. Previous ESR/U-series analyses of Isernia fossil teeth have displayed both recent U-uptake and severe underestimation of the ESR/U-series dates in comparison with the (39)Ar/(40)Ar age. In order to identify the cause of this age underestimation, new analyses were realized in the present study on four bovid teeth directly recovered from the archaeological surface t3a. The ESR/U-series dates obtained were once again strongly underestimated, with an error weighted mean age of 435 +/- 24 (1 sigma) ka. These too young dates could be associated to a change of the environmental gamma-dose rate during the geological history of the Isernia site, related to the revealed recent U-uptake into the palaeontological remains of the archaeological level. If we consider that this dose rate change was coeval with a wet interglacial period and taking the (39)Ar/(40)Ar age as geochronological reference, simulations with two dose rate steps indicate that this change could be correlated with marine isotopic stage 7 (MIS 7). (C) 2011 Elsevier Ltd. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
