On the limits of using combined U-series/ESR method to date fossil teeth from two Early Pleistocene archaeological sites of the Orce area (Guadix-Baza basin, Spain)

Abstract

The combined U-series/electron spin resonance (ESR) dating method was applied to nine teeth from two Early Pleistocene archaeological sites located in the Orce area (Guadix-Baza Basin, Southern Spain): Fuente Nueva-3 (FN-3) and Barranco León (BL). The combination of biostratigraphy and magnetostratigraphy places both sites between the Olduvai and Jaramillo subchrons (1.78–1.07 Ma).Our results highlight the difficulty of dating such old sites and point out the limits of the combined U-series/ESR dating method based on the US model. We identified several sources of uncertainties that may lead to inaccurate age estimates. Seven samples could not be dated because the dental tissues had (230Th/234U) activity ratios higher than equilibrium, indicating that uranium had probably leached from these tissues. It was however possible to calculate numerical estimates for two of the teeth, both from FN-3. One yielded a Middle Pleistocene age that seems to be strongly underestimated; the other provided an age of 1.19 ± 0.21 Ma, in agreement with data obtained from independent methods. The latter result gives encouragement that there are samples that can be used for routine dating of old sites.

Walk the line: 600000 years of molar evolution constrained by allometry in the fossil rodent Mimomys savini

“…The sequence consists of nine samples associated with absolute ages. Their chronology (table 1) was taken from Lozano-Fernández et al [25,26] and updated according to recent absolute dating [39,40]. Molar length and width (figure 1) have Table 1.…”

Faunas from Atapuerca at the Early–Middle Pleistocene limit: The ungulates from level TD8 in the context of climatic change

“…The next locality that records these changes is Atapuerca TE9, dated to 1220 +/-140 ka, and the underlaying TE7, dated to 1130 +/-180 ka , resulting in a likely age of a little less than 1.2 Ma. Given the differences in fauna, these localities are probably younger than Fuente Nueva 3, which has been dated to 1.19±0.21 Ma (Duval et al, 2012). The next oldest localities are Jaramillo in age.…”

Defending the early human occupation of Vallparadís (Barcelona, Iberian Peninsula): A reply to

“…Or as Madurell-Malapeira et al (2012: 172) put it: "significant changes in human behavior and paleoecology did not occur until slightly later in time, probably around the EarlyMiddle Pleistocene boundary." Furthermore, the geochronological and biochronological data from level 10 at Vallparadís situate it close to the Jaramillo subchron (0.98 Ma; Martínez et al, 2010), whilst the Iberian sites of Orce, Barranco León and Fuente Nueva 3 are dated to 1.4e1.2 Ma (Martínez-Navarro et al, 1997;Oms et al, 2000;Agustí and Madurell, 2003;Duval et al, 2012), and the Atapuerca sites of Sima del Elefante and Gran Dolina TD6 are dated to 1.22 AE 0.16 Ma and 0.88e0.78 Ma, respectively (Carbonell et al, 1995(Carbonell et al, , 2008Moreno-García, 2011). On the basis of this we can therefore state that these sites in Western Mediterranean Europe were repeatedly and perhaps continually occupied from 1.4 to 1.2 Ma until the EarlyMiddle Pleistocene (0.78 Ma), thus closing the chronological gap in the Late Early Pleistocene of the Iberian Peninsula (Garcia et al, 2011a;contra;Madurell-Malapeira et al, 2012;Duval et al, in press).…”