# ESR/U-series chronology of the Lower Palaeolithic palaeoanthropological site of Visogliano, Trieste, Italy

Christophe Falguères, Jean-Jacques Bahain, Carlo Tozzi, Giovanni Boschian, Jean-Michel Dolo, Norbert Mercier, Hélène Valladas, Yuji Yokoyama

► To cite this version:

Christophe Falguères, Jean-Jacques Bahain, Carlo Tozzi, Giovanni Boschian, Jean-Michel Dolo, et al. ESR/U-series chronology of the Lower Palaeolithic palaeoanthropological site of Visogliano, Trieste, Italy. Quaternary Geochronology, 2008, 3 (4), pp.390-398. 10.1016/j.quageo.2008.01.007. hal-03192695

HAL Id: hal-03192695

https://hal.science/hal-03192695v1

Submitted on 11 Mar 2025

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
# ESR/U-series chronology of the Lower Palaeolithic palaeoanthropological site of Visogliano, Trieste, Italy

Christophe Falguères<sup>a</sup>, Jean-Jacques Bahain<sup>a</sup>, Carlo Tozzi<sup>b</sup>, Giovanni Boschian<sup>b</sup>, Jean-Michel Dolo<sup>c</sup>, Norbert Mercier<sup>d</sup>, Hélène Valladas<sup>d</sup>, Yuji Yokoyama<sup>a</sup>

<sup>a</sup> Département de Préhistoire du Muséum National d'Histoire Naturelle, UMR 5198CNRS, 1, rue René Panhard, 75013 Paris, France

<sup>b</sup> Dipartimento di Scienze Archeologiche, Universita' di Pisa, 53, Via S. Maria, I-56100 Pisa, Italy

<sup>c</sup> Laboratoire National Henri Becquerel, CEA Saclay, 91191 Gif-sur-Yvette, France

<sup>d</sup> Laboratoire des Sciences du Climat et de l'Environnement, CNRS-CEA, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France

## Abstract

The Visogliano shelter, in north-eastern Italy, is an important Middle Pleistocene occupation site where human remains were found together with an archaic lithic industry, including choppers, chopping tools and a few protobifaces. It is of utmost importance to try to document this period, when a second wave of settlement colonised Western Europe, carrying new flaking techniques and tools.

Combined ESR/U-series analyses, integrated with biostratigraphical and environmental data, define a chronological frame for the layers from which the artefacts were unearthed. The lower levels, including human remains, can be dated to the 350–500 kyr time span, in agreement with micromammal and stratigraphical studies.

These data make Visogliano one of the oldest palaeoanthropological sites in Italy, where human remains are directly associated with protobifaces, choppers and chopping tools. In Western Europe, Visogliano is contemporaneous to the G soil of the Arago Cave, France, with which it shares several similarities in faunal assemblages and radiometric data, and which contains human remains also. These data make Visogliano as one of the oldest sites in Europe where the Acheulian culture is observed.

**Keywords:** Visogliano, Middle Pleistocene, Combined ESR/U-series method, Human remains

## 1. Introduction

The Lower Palaeolithic palaeoanthropological site of Visogliano is located in the Trieste Karst, in northern Italy (Fig. 1). It was discovered in 1974 by A. Marcucci, a local amateur, and the first archaeological and geological studies were immediately started by the Department of Earth Sciences of the Ferrara University (Bartolomei et al., 1977; Bartolomei and Tozzi, 1979); the Department of Archaeological Science of the Pisa University has been carrying on yearly excavation since 1983.
<figure><img src="image_2.png" /><figcaption>Fig. 1. Location of the Visogliano site, which is about 15 km northeast of Trieste city, Italy.</figcaption></figure>

Sequences of Middle Pleistocene archaeological sediments, including human remains, lithics, human-
processed faunas and micromammal fauna were unearthed in two distinct loci of a karstic doline
originated by the collapse of a cave: a rock shelter (locus A, Fig. 2), and an outcrop of well-cemented
breccia (locus B), about 30 m to the west of the shelter (Fig. 3); both are situated at the edge of the
doline. A total sequence of about 12 m was studied (Cattani et al., 1991; Tozzi, 1994).

<figure><img src="image_3.png" /><figcaption>Fig. 2. Stratigraphical sketch of Shelter A and of Breccia B. The lowest layers of the first one exhibit similarities with those of Breccia B, which lay unconformably on Onyx layer, which represents the first testimony of the karst activity.</figcaption></figure>
<figure><img src="image_4.png" /><figcaption>Fig. 3. Longitudinal excavation profile of Visogliano locus A (shelter): (1) living floors; (2) loess levels; (3) altered loess levels; (4) limits of lithological units and (5) major unconformities/paraconformities. The numbers on the left hand side correspond to the archaeological levels. The ages, on the extreme left hand side, are presented in kyr.</figcaption></figure>

Such a long sequence of almost continuous human occupation of this period provides high-quality information on the peopling and cultures of Western Europe during the Middle Pleistocene and on the diffusion of hominid species through the continent. Geochronometric datings are of greatest importance in this case, in order to refine the chronology of the sequence, and insert it into the framework of Middle Pleistocene stratigraphy. ESR and U-series analyses on teeth of various herbivore species were carried out on samples collected from selected levels, covering the whole sequence.
## 1.1. Site stratigraphy

The sequence of locus B is about 3 m thick; it lies unconformably over a thick speleothem, locally called “onyx”, which corresponds to the first known karstic processes of Pleistocene age within the area (Boschian et al., 2002). The breccia levels include large speleothem fragments deriving from the collapse of the cave; geological, faunal and pollen data suggest deposition under humid, non-glacial conditions.

Unfortunately, a direct stratigraphical correlation between the breccia and the shelter is precluded by an erosion surface, filled up with Upper Pleistocene red soils and calcareous blocks. Nevertheless, a tentative correlation can be established: faunal, pollen and stone tool assemblages, and sediments of locus B are similar to those observed in the lower levels (layers 44–41) of the shelter, even if the characteristics are not exactly the same. Moreover, the breccia layers plunge towards the shelter (locus A) with a dip that is compatible with the depth of layers 44–41 (Fig. 3).

The sequence of locus A is at present about 10 m thick, but the bedrock has not been reached yet. The lower part (levels 46–40) is characterised by sediments, and pollen and faunal assemblages suggesting a mild climate phase (Dama clactoniana, Felis sylvestris, Macaca sp., Microtus sp., Crocidura sp.). Clay loam colluvia are interfingered and mixed with limestone and/or speleothem rubble deriving from the collapse of the karstic system. It is noteworthy that a large part of the gravel-size fraction of the deposit is made up of flaked limestone tools and debris.

The deposits of the upper part (levels 39–11) can be grouped into three main *facies*: breakdown deposits (large blocks and/or frost slabs), loessic sediments and colluvia of red soils previously developed outside the cave. Alternating cold and dry-cold phases, with major ceiling breakdown events and loess deposition, occur in the upper part of this sequence. This 7 m thick part includes several unconformities that in some cases derive from erosional events, in other cases from changes in the depositional style, and finally also from human activities; whichever their origin, a perfect cyclicity in the sequence cannot be expected.

Two major breakdown phases can be observed in levels 30–29 and 18–17. Apparently, both lie on non-erosional unconformities/paraconformities and are followed first by deposition of frost slabs (28–26 and 16–14) and then by loess (25 and 12–11). The second of these sequences is complicated by an anthropogenous erosion feature (bottom of level 13), upon which a living floor can be observed. One major colluvium level (22–23) followed by frost-slab deposition (24) separates these two cycles.

Recent (Upper Pleistocene) clay colluvium (level 10) creeped into a fissure that opened between the wall of the shelter and its infilling because of the compaction of the sediments.

Summing up, the sequence of locus B and the lower part of the sequence of locus A can be ascribed to a mild climate phase with good forest cover. The upper part of sequence A corresponds to a colder phase; within this one, loess occurs seldom within the lower levels, while it is more common in the upper ones, probably testifying to dryer conditions; it is usually associated with abundant *Ochotona* sp. remains. Other faunal remains of open environment (*Stephanorhinus hundsheimensis*, *Equus* sp., *Ovis ammon antiqua*, *Citellus* sp., *Microtus* (*Stenocranius*) *gregalis*) also indicate cold and aridic, probably steppe conditions.

The above-cited species, together with the others found within the upper and lower parts of locus A deposits (*Ursus deningeri*, *Cervus elaphus acoronatus*, *Sorex runtonensis*, *Macroneomys* sp., *Arvicola cantianus* and *Pliomys episcopalis*) show that the sequence can be ascribed to the middle part of the Middle Pleistocene (Cattani et al., 1991). Moreover, the changes in dental evolution of *A. cantianus* suggest placing the sequence of Visogliano between the Isernia–Mosbach phase and the lower
travertines of Ehringsdorf, corresponding to the marine oxygen isotope stages 13–12 or 11–10 (Abbazzi et al., 2000; Maul et al., 1998). The faunal assemblage of Visogliano is more similar to the faunal assemblage of the Arago Middle complex (France) than to those of other contemporaneous Italian sites (Moigne et al., 2006).

**1.2. Anthropological remains**

A fragment of a robust human mandible, five teeth and a root and two crown fragments were unearthed from different levels of the two loci (Cattani et al., 1991; Mallegni et al., 2002).

* One tooth (Vis.1), a fragment of jaw (Vis.2, Fig. 4) and two fragments of human teeth (a fragment of a molar crown and the root of an incisor) were found in the layers of Breccia B.

<figure><img src="image_5.png" /><figcaption>Fig. 4. View of the Visogliano robust human mandible fragment (Vis.2): (a) occlusal view and (b) right lateral view.</figcaption></figure>

* Four teeth were discovered within the layers of shelter A between 1992 and 1996: Vis.6 ($M^1$ right) comes from level 45; Vis.4 ($P^1$ left) and Vis.5 ($P^2$ left) were found in layer 44; Vis.3 ($M^2$ right) was found in level 42. They belong to two individuals; according to Abbazzi et al. (2000), their shape and size resemble the most ancient western (archaic *Homo sapiens*) and eastern (*Homo erectus*) specimens of the Middle Pleistocene.

The lithic assemblage of the older levels (46–40 of shelter A and almost all of Breccia B), is made up of discoidal cores, choppers, flakes with a few retouched elements and some protobifaces, mainly flaked on local limestone (87%). In these levels, and particularly in level 43, few artefacts made on volcanic rock were recovered (less than 1%). Flint raw material is dominant from level 39 upwards. The choppers disappear, and the tool assemblage of levels 39–37 is strongly microlithic, with a high percentage of denticulates. For the lowest levels of Visogliano A and for Breccia B, a “Lower Tayacian” group has been identified, while a specific “denticulate” group can be identified in layers 39–37 of Shelter A. The upper horizon can be ascribed to the Tayacian, with frequent carinated and Quinson-like tools, mainly collected in layers 25–22, 13 and 12 (Grifoni and Tozzi, 2006; Palma di Cesnola, 1996).
## 1.3. Preliminary datings

The mandible Vis.2 was dated by non-destructive gamma-ray spectrometry at the Département de Préhistoire of Muséum national d'Histoire naturelle of Paris. The sample was placed on a low background and high-purity germanium detector (Yokoyama and Nguyen, 1980) and was measured for 17 days. The method is based on the uranium-series principle (see Ivanovich and Harmon, 1992). The age is determined from the measurement of $^{230}$Th/$^{234}$U and $^{231}$Pa/$^{235}$U ratios. The main advantage of this method is the non-destructiveness, and hence it allows the dating of precious samples like human remains (Yokoyama et al., 1997). Gamma rays emitted by nuclides involved in the dating have very weak intensities and energies. The activities of $^{234}$U and $^{230}$Th are directly determined from their gamma-ray peaks, respectively, at 53.3 and 67.7 keV. The activity of $^{238}$U is determined from the gamma rays of its short-lived daughter, $^{234}$Th (63.3 and 92.5 keV). An age of 390 kyr with a large error range was obtained for the mandible fragment using the $^{230}$Th/$^{234}$U ratio (Table 1).

<table><caption>Table 1. U content, isotopic ratios and age of the Vis.2 mandible</caption><thead><tr><td>Sample</td><td>Mandible Vis.2</td></tr></thead><tbody><tr><td>U (ppm)</td><td>17.9</td></tr><tr><td><sup>234</sup>U/<sup>238</sup>U</td><td>891 ± 0.453</td></tr><tr><td><sup>230</sup>Th/<sup>234</sup>U</td><td>1.135 ± 0.276</td></tr><tr><td><sup>230</sup>Th/<sup>232</sup>Th</td><td>150</td></tr><tr><td>AGE (kyr)</td><td>390 + indet./-229</td></tr></tbody></table>

The mandible fragment (15.47 g) has been measured for 17 days on a high-purity and low-background germanium detector.

Uncertainties for isotopic ratios are given with ±1 sigma.

## 2. Methods and materials

Combined U-series (see details in Ivanovich and Harmon, 1992) and ESR methods (Falguères and Bahain, 2002; Grün, 1989; Ikeya, 1993) were used to date the samples from Visogliano. Both depend on the mode of uranium uptake in fossil teeth, which can be described by mathematical models; in most cases, it is comprised of the early uptake (EU) and the linear uptake (LU) models. The former assumes that uranium was incorporated shortly after burial (Bischoff and Rosenbauer, 1981), while the latter considers a constant rate of uranium uptake since the time of burial (Ikeya, 1982). The combined ESR/U-series method allows the calculation of the history of uranium uptake using the uptake parameter *p* (Grün et al., 1988).

Several herbivore teeth collected from levels 44 (Vi9801; bison, Vi9802; rhinoceros), 41 (Vi9803; bison), 38 (Vi9804; horse), 24 (Vi9805; cervid), 15 (Vi9806; horse), 13 (Vi9807; horse) and 11 (Vi9808; rhinoceros) were analysed. All the samples were in good state of preservation. The analysed enamel was taken on the external part of each crown, which were not worn out.

The various tissues were separated mechanically. The enamel was ground, sieved (100–200 µm) and split into 10 aliquots for irradiation, after the cleaning of its outer surface to remove the effect of external alpha radiation. No cementum layer was observed except for the horse teeth (Vi9806, Vi9807). In this case, the age calculation was carried out following the dentine–enamel–cementum model, while for the other samples a dentine–enamel–sediment model was used (see Table 3 caption).
The enamel samples were irradiated with doses of 52, 98, 187, 410, 748, 1866, 2835, 5729 and 9619 Gy, using a calibrated $^{60}$Co gamma-ray source. The ESR measurements were performed at room temperature on a Varian E-109 X-band spectrometer, with a microwave power of 10 mW, and amplitude modulation of 1 G. A scan range of 100 G and a time constant of 4 min with a modulation frequency of 100 kHz were used for each spectrum. The equivalent doses D$_{E}$ were determined from the asymmetric enamel signal at g=2.0018 by the additive method, using an exponential fitting (Yokoyama et al., 1985). Each ESR measurement was repeated three times for each dose.

U-series analyses were made on each dental tissue, using alpha-ray spectrometry and according to the standard methods described by Bischoff et al. (1988), at the Department of Prehistory of Muséum National d'Histoire Naturelle, Paris.

ESR age calculations were carried out by the ESR-DATA program (Grün, 2005) using an alpha efficiency of 0.13±0.20 (Grün and Katzenberger-Apel, 1994) and Monte-Carlo beta attenuation factors (Marsh, 1999), based on the thickness of the tooth enamel and of the removed outer layers. In addition, the following parameters were used:

* water content was estimated to be 3 wt% in the enamel, 7 wt% in the dentine and in the cementum and 15 wt% in the sediment, based on the wet weight;

* gamma-ray spectrometry was used to determine the radioisotope (U, Th and K) content of the sediments where the teeth were collected; the dose rate was calculated according to Adamiec and Aitken (1998);

* The effect of Rn loss in each tissue was determined by combining alpha-ray and gamma-ray data (Bahain et al., 1992).

**3. Results and discussion**

Table 2 summarises the radiometric data of the Visogliano samples. U content in enamel varies between 0.7 and 7.7 ppm, with a general value around 3 ppm. U content in dentine and cementum ranges between 95 and 178 ppm, except for rhinoceros teeth, where this value is two or three times lower (around 57–60 ppm). The Ra and Rn losses in enamel are slight for most samples, but range between 0.15 and 0.70 in the other tissues. All the samples show $^{230}$Th/$^{232}$Th ratios greater than 100, suggesting that no detrital thorium is suspected to contaminate the samples.
<table><caption>Table 2. ESR and U-series data of fossil herbivore teeth from Visogliano</caption><thead><tr><th>Sample</th><th>Faunal species</th><th></th><th>U (ppm)</th><th><sup>234</sup>U/<sup>238</sup>U</th><th><sup>230</sup>Th/<sup>234</sup>U</th><th><sup>226</sup>Ra/<sup>230</sup>Th</th><th><sup>222</sup>Rn/<sup>230</sup>Th</th><th>T enamel (mm)</th><th>Removed enamel (mm)</th><th>D<sub>E</sub> (GY)</th></tr></thead><tbody><tr><td rowspan="2">VI9801</td><td rowspan="2">Bovid</td><td>D</td><td>177.88</td><td>1.058±0.009</td><td>0.836±0.014</td><td>0.43</td><td>0.25</td><td></td><td></td><td></td></tr><tr><td>E</td><td>7.69</td><td>1.233±0.025</td><td>0.839±0.028</td><td>0.94</td><td>0.84</td><td>1.60</td><td>0.30</td><td>1291±62</td></tr><tr><td rowspan="2">VI9802</td><td rowspan="2">Rhinoceros</td><td>D</td><td>56.87</td><td>1.644±0.020</td><td>1.045±0.034</td><td>0.24</td><td>0.14</td><td></td><td></td><td></td></tr><tr><td>E</td><td>2.97</td><td>1.154±0.039</td><td>0.813±0.038</td><td>1.0</td><td>0.75</td><td>2.80</td><td>0.50</td><td>545±23</td></tr><tr><td rowspan="2">VI9803</td><td rowspan="2">Bovid</td><td>D</td><td>122.60</td><td>1.084±0.013</td><td>0.882±0.019</td><td>0.47</td><td>0.28</td><td></td><td></td><td></td></tr><tr><td>E</td><td>3.37</td><td>1.116±0.029</td><td>0.827±0.031</td><td>1.0</td><td>1.0</td><td>1.30</td><td>0.20</td><td>668±19</td></tr><tr><td rowspan="2">VI9804</td><td rowspan="2">Horse</td><td>D</td><td>122.07</td><td>1.269±0.015</td><td>0.911±0.026</td><td>0.60</td><td>0.31</td><td></td><td></td><td></td></tr><tr><td>E</td><td>2.22</td><td>1.344±0.049</td><td>0.903±0.039</td><td>0.73</td><td>0.71</td><td>1.30</td><td>0.20</td><td>857±34</td></tr><tr><td rowspan="2">VI9805</td><td rowspan="2">Deer</td><td>D</td><td>118.28</td><td>1.180±0.015</td><td>0.911±0.019</td><td>0.47</td><td>0.28</td><td></td><td></td><td></td></tr><tr><td>E</td><td>3.01</td><td>1.253±0.035</td><td>0.944±0.034</td><td>0.61</td><td>0.57</td><td>1.30</td><td>0.15</td><td>1166±49</td></tr><tr><td rowspan="3">VI9806</td><td rowspan="3">Horse</td><td>C</td><td>103.41</td><td>1.332±0.015</td><td>0.840±0.028</td><td>0.59</td><td>0.31</td><td></td><td></td><td></td></tr><tr><td>D</td><td>105.46</td><td>1.141±0.015</td><td>0.771±0.017</td><td>0.61</td><td>0.37</td><td></td><td></td><td></td></tr><tr><td>E</td><td>3.07</td><td>1.333±0.034</td><td>0.786±0.029</td><td>1.0</td><td>1.0</td><td>1.50</td><td>0.15</td><td>863±29</td></tr><tr><td rowspan="3">VI9807</td><td rowspan="3">Horse</td><td>C</td><td>95.22</td><td>1.382±0.023</td><td>0.873±0.023</td><td>0.67</td><td>0.37</td><td></td><td></td><td></td></tr><tr><td>D</td><td>116.31</td><td>1.183±0.018</td><td>0.888±0.022</td><td>0.46</td><td>0.26</td><td></td><td></td><td></td></tr><tr><td>E</td><td>3.07</td><td>1.343±0.045</td><td>0.777±0.032</td><td>1.0</td><td>1.0</td><td>1.50</td><td>0.15</td><td>1721±76</td></tr><tr><td rowspan="2">VI9808</td><td rowspan="2">Rhinoceros</td><td>D</td><td>59.92</td><td>1.192±0.028</td><td>1.108±0.035</td><td>0.52</td><td>0.34</td><td></td><td></td><td></td></tr><tr><td>E</td><td>0.69</td><td>1.198±0.079</td><td>0.909±0.062</td><td>1.0</td><td>0.69</td><td>1.80</td><td>0.36</td><td>922±33</td></tr></tbody></table>

E, enamel; D, dentine; C, cementum; uncertainties for isotopic ratios are given with ±1 sigma. The initial (T) and removed enamel thicknesses are used for age calculation. Equivalent doses D<sub>E</sub> were determined through exponential fitting by the additive dose method.
<table><caption>Table 3. Components of dose rates for US model of teeth and sediment, and combined ESR and U-series age estimates with the corresponding *p*-values for fossil teeth from Visogliano site</caption><thead><tr><th rowspan="2">Sample</th><th rowspan="2">β+γ<br>Sediment<br>+cosmic<br>(μGy/yr)</th><th colspan="4">Components of dose rates for US model</th><th colspan="4">ESR and U-series combined data (US model)</th></tr><tr><th>Internal<br>dose rate<br>α+β enamel<br>(μGy/yr)</th><th>β Dose rate<br>dentine<br>(μGy/yr)</th><th>β Dose rate<br>cementum<br>(μGy/yr)</th><th>Total dose<br>rate<br>(μGy/yr)</th><th>p Enamel</th><th>p Dentine</th><th>p<br>Cementum</th><th>Age (kyr)</th></tr></thead><tbody><tr><td colspan="10"><em>Level 44</em></td></tr><tr><td>Vi9801</td><td>354</td><td>1874</td><td>461</td><td>–</td><td>2685</td><td>-0.26±0.18</td><td>-0.31±0.17</td><td>–</td><td>482+99/-81</td></tr><tr><td>Vi9802</td><td>315</td><td>650</td><td>219</td><td>–</td><td>1185</td><td>-0.25±0.13</td><td>-0.78±0.40</td><td>–</td><td>439+58/-54</td></tr><tr><td colspan="10"><em>Level 41</em></td></tr><tr><td>Vi9803</td><td>372</td><td>850</td><td>513</td><td>–</td><td>1735</td><td>-0.52±0.10</td><td>-0.73±0.07</td><td>–</td><td>356+46/-41</td></tr><tr><td colspan="10"><em>Level 38</em></td></tr><tr><td>Vi9804</td><td>920</td><td>653</td><td>523</td><td>–</td><td>2098</td><td>-0.65±0.05</td><td>-0.70±0.05</td><td>–</td><td>383+38/-36</td></tr><tr><td colspan="10"><em>Level 24</em></td></tr><tr><td>Vi9805</td><td>959</td><td>859</td><td>517</td><td>–</td><td>2335</td><td>-0.73±0.04</td><td>-0.65±0.05</td><td>–</td><td>445+45/-42</td></tr><tr><td colspan="10"><em>Level 15</em></td></tr><tr><td>Vi9806</td><td>1171</td><td>864</td><td>369</td><td>369</td><td>2772</td><td>-0.58±0.07</td><td>-0.58±0.08</td><td>-0.73±0.06</td><td>266+24/-23</td></tr><tr><td colspan="10"><em>Level 13</em></td></tr><tr><td>Vi9807</td><td>1295</td><td>676</td><td>351</td><td>256</td><td>2580</td><td>+0.11±0.13</td><td>-0.51±0.06</td><td>-0.38±0.07</td><td>480+47/-45</td></tr><tr><td colspan="10"><em>Level 11</em></td></tr><tr><td>Vi9808</td><td>1945</td><td>219</td><td>211</td><td>–</td><td>2374</td><td>-0.79±0.03</td><td>-1<sup>*</sup></td><td>–</td><td>346+24/-23</td></tr></tbody></table>

External dose rates correspond to both sediment dose and cosmic dose (β+γ). Two types of measurements have been performed. About 100 g of sediment including rock fragments when they are present, was measured at least 1 month after it had been inserted in a box. Sediments have been sampled in the same square and at the same height as the teeth. On the other hand, three TL dosimeters have been placed in levels 44, 38 and 24 at the exact location of the
analysed sediments. Vi9802 and Vi9808 are rhinoceros teeth with enamel and dentine, but lacking a cementum layer, which does not exist for this species. Vi9801 and Vi9803 are bovid teeth and Vi9805 is a cervid tooth in which the cementum was not observed or not sufficient to be analysed. A similar observation can be made for equid tooth Vi9804. For these samples, the enamel was directly in contact with the sediment. The case dentine–enamel– cementum was used for some equid teeth (Vi9806 and Vi9807), the cementum layer was thick enough to prevent the enamel from sediment beta particles.

* p-value was limited to -1, suggesting leaching uranium.
Table 3 details ESR dose rates. The external dose rate was measured by gamma-ray spectrometry. It includes the cosmic dose rate taking into account the depth of each layer (Prescott and Hutton, 1988a, Prescott and Hutton, 1988b). Three TL dosimeters were also used for levels 44, 38 and 24. They give external dose rates 15-25% smaller than those obtained by gamma-ray measurements on sediment in the laboratory. These data are not surprising because the layers are not homogeneous, and dosimeters take into account also the calcareous blocks that usually contain less U, Th and daughters and K than clay. All the teeth have been sampled during the previous excavation campaigns before we put the dosimeters in the levels at an arbitrary position but which represented well the heterogeneity of the layers.

The contribution of the external dose rate to the total one, for US model, ranges between 14% and 26% for the lower levels (44 and 41) and between 42% and 82% for the upper levels (38–11, Fig. 5).

<figure><img src="image_6.png" /></figure>

Fig. 5. Alpha, beta and gamma dose contributions to the total annual dose in percentage for the analysed samples of Visogliano.

U–Th ages obtained on enamel, systematically younger than the EU-ESR ones, suggest that after-burial uranium uptake directly affected the U–Th ages. For each tissue, a *p*-value was determined using combined ESR/U-Th data. Table 3 presents the combined ESR/U-series age estimates for each sample.

The US-ESR ages of the oldest analysed levels (44 and 41) range between 482 and 356 kyr, with a wide error range of 15–20%. Water content in sediment was estimated to be 15%.

The combined age estimates of the intermediate levels (39–24) range between 445 and 383 kyr. This may suggest that these layers were deposited contemporarily to (or very short after) the lowest ones, in evident contrast with the abrupt change in pedosedimentary conditions and faunal content that can be observed between layers 40 and 39; also the difference in external dose rate is strong, as it becomes three times higher than in the lower levels. On the other hand, it must be pointed out that any stratigraphic inference is highly disputable from level 37 downwards, as all the information about the lower layers derive from a 2×2 m explorative pit excavated during the 1990s.

The combined age obtained on the tooth extracted from level 15 (Vi9806) is 266 +24/-23 kyr, which indicates a younger age for this level. On the other hand, samples Vi9807 and Vi9808 (levels 13 and 11) provide too old ages, which are inconsistent with all the other geochronological and stratigraphical data. In fact, these samples were unearthed during the first excavation campaigns, and their
stratigraphical position is somewhat disputable. Moreover, an accurate *in situ* dosimetry of these levels
has not been carried out yet.

The ESR/U-Th ages of levels 44-41 can be compared to the direct U-series age (Table 1) obtained on
the Vis.2 mandible fragment found in the breccia levels of locus B. The agreement between the
gamma and ESR/US age may be fortuitous because of the large error range obtained on the first one.
However, these two layer sets can be considered as roughly contemporaneous, as indicated by their
stratigraphical correlations and faunal content as suggested later.

This correlation also suggests that the lowest levels excavated so far in the site were deposited during
the Marine Isotope Stage MIS 11 or, more likely, 13. In fact, it looks unlikely that all the sequence can
be squeezed into the MIS 11-10 time span, also because the “cold” levels are very well developed at
Visogliano, while MIS 10 is usually poorly represented in the marine isotope sequences. It may be
then inferred that the “cold” levels represent MIS 12 and 10, while MIS 11 is very poorly represented
because it was largely eroded from the sequence.

In accordance with this hypothesis, pollen spectra from the lowest levels (45-40) of locus A indicate
typical temperate wood environments, with oak, pines and thermophilous trees of mediterranean
species such as *Pistacia* that would fit into a warm stage.

Moreover, the geochronometric data fit also the micromammal morphometric-evolutionary
chronology of Breccia B and layers 45-43 (Abbazzi et al., 2000). This method is based mainly on the
measurement of tooth enamel thickness of arvicolids (*Arvicola* and *Microtus*), which show a general
trend of reduction of the values in the lineage *Microtus savinii*–*A. cantianus*- *Arvicola terrestris* (Maul
et al., 1998). Chronological calibrations insert the Visogliano sequence between Isernia and
Erhingsdorf.

At Isernia, two pyroclastic layers embedding sanidine crystals, i.e. Unit 1 (layer 3C) and Unit 3 (layer
3E), have recently been dated by the Ar/Ar method (Coltorti et al., 2005). The radiometric results
constrain the age of the Isernia facies, which contains a rich palaeontological and archaeological
assemblage (Peretto, 1996). An age of about 600 kyr has been obtained for the anthropological layers
of Unit 3; conversely, scattered Ar/Ar results suggest that layer 3C of Unit 1 was partially reworked,
and provide a maximum age of 475 kyr for the youngest samples.

The oldest layers of Visogliano (44-41) are coeval with the Arago Middle Stratigraphic Complex
according to the faunal assemblage (Crégut, 1980; Guérin, 1981; Guérin and Faure, 1991; Moigne et
al., 2006) and also with the radiometric data, which assign an age >350 kyr to the human fossils of soil
G of Unit III that lies stratigraphically beneath the stalagmitic formation of Unit IV (Falguères et al.,
2004).

**4. Conclusion**

Radiometric data obtained from several levels of the Visogliano sequence suggest a relatively rapid
deposition ranging between 500 and 350 kyr. It must be pointed out that, despite clear differences in
environmental and geological characteristics between the older levels (46-40) and the younger ones
(39-24), there is no age variation if we take into account the error range. It must also be observed that
the Visogliano sequence is still poorly known, mostly on the bottom levels, where more
disconformities are expected to appear; new excavations in the deeper levels, together with a
refinement of the geochronometric data and more detailed palaeontological analyses should shed new
light on the timing of the site.
The human occupation can be reasonably located within MIS 13 and 10. Because of the similarities between the faunal assemblages of Visogliano and those of the bottom of the Middle Stratigraphic Complex of Arago site, the radiometric results of Visogliano (lower levels) may be constrained to the time span between 400 and 500 kyr.

These US-ESR dates suggest a possible coexistence of human groups with different cultural traditions in Italy (Grifoni and Tozzi, 2006). These results place Visogliano within the oldest Tayacian sites in Western Europe (Fig. 6), together with other relevant sites like Fontana Ranuccio. Here, handaxes and other artefacts were recovered from a tephra layer dated to 458±6 kyr by K/Ar, while the fauna suggests an age within MIS 11 and a temperate open environment (Segre and Ascenzi, 1984). Visogliano is also contemporary to the oldest Acheulian sites known at present in Northern Europe, such as Boxgrove (UK), dated to 420–520 kyr by combined stratigraphic and biostratigraphic data (Roberts et al., 1994), and Cagny-la-Garenne dated to around 450 kyr by ESR on sediment and fossil herbivore teeth (Bahain et al, 2007).

<figure><img src="image_7.png" /></figure>
Fig. 6. Chronological position of the different studied sites versus marine isotope stages taken from Bassinot et al. (1994).

## Acknowledgements

This work has been partially financed by the Centre National de la Recherche Scientifique in the frame of "Paléoenvironnement, Evolution des Hominidés" programme. We thank Rainer Grün, Australian National University, for his help in the age calculations and two anonymous referees for their helpful comments.

## References

L. Abbazzi, F. Fanfani, M.P. Ferretti, L. Rook, L. Cattani, F. Masini, F. Mallegni, F. Negrino, C. Tozzi. New human remains of archaic homo sapiens and Lower Palaeolithic industries from Visogliano (Duino Aurisina, Trieste, Italy). Journal of Archaeological Science, 27 (2000), pp. 1173-1186

G. Adamiec, M.J. Aitken. Dose-rate conversion factors: update. Ancient TL, 16 (1998), pp. 37-50

J.J. Bahain, Y. Yokoyama, C. Falguères, M.N. Sarcia. ESR dating of tooth enamel: a comparison with K–Ar dating. Quaternary Science Review, 11 (1992), pp. 245-250

J.J. Bahain, C. Falguères, M. Laurent, P. Voinchet, J.M. Dolo, P. Antoine, A. Tuffreau. ESR chronology of the Somme river terrace system and first human settlements in northern France, Quaternary Geochronology, 2 (2007), pp. 356-362

G. Bartolomei, C. Tozzi. Nuovi dati stratigrafici sui depositi del Pleistocene medio a Ochotona del Riparo di Visogliano nel Carso di Trieste. Atti della Academia Nazionale dei Lincei, 64 (1979), pp. 490-497

G. Bartolomei, C. Peretto, B. Sala. Depositi a loess con Ochotona e rinoceronte nel carso di Trieste. Atti della Academia Nazionale dei Lincei, 61 (1977), pp. 280-285

F.C. Bassinot, L. Labeyrie, E. Vincent, X. Quidelheur, N.J. Shackleton, Y. Lancelot. The astronomical theory of climate and the age of the Brunhes–Matuyama magnetic reversal. Earth Planet Science Letter, 126 (1994), pp. 91-108

J.L. Bischoff, R.J. Rosenbauer. Uranium-series dating of human skeletal remains from the Del Mar and Sunnyvale sites, California. Science, 213 (1981), pp. 1003-1005

J.L. Bischoff, R.J. Rosenbauer, A. Tavoso, H. Lumley de. A test of uranium-series dating of fossil tooth enamel: results from Tournal cave, France. Applied Geochemistry, 3 (1988), pp. 135-141

Boschian, G., Cattani, L., Romagnoli, S., 2002. L’“Onice del Carso” in località Fornace Aurisina (Trieste, Italy). Studio sedimentologico e palinologico. Razprave IV, Razreda Slovenska Akademia Znanosti in Umetnosti, XLIII–2, 31–40, Ljubljana.

L. Cattani, M. Cremaschi, M.R. Ferraris, F. Mallegni, F. Masini, V. Scola, C. Tozzi. Le gisement du Pléistocène moyen de Visogliano (Trieste): restes humains, industries, environnement. L'Anthropologie, 91 (1991), pp. 9-36

M. Coltorti, G. Féraud, A. Marzoli, C. Peretto, T. Ton-That, P. Voinchet, J.J. Bahain, A. Minelli, U. Thun Hohenstein. New 40Ar/39Ar, stratigraphic and palaeoclimatic data on the Isernia la Pineta Lower Palaeolithic site, Molise, Italy. Quaternary International, 131 (2005), pp. 11-22
E. Crégut. La faune de mammifères du gisement pléistocène moyen antérissien de la Caune de l'Arago (Tautavel, Pyrénées-Orientales, France). Comptes Rendus Académie des Sciences de Paris, 290 (1980), pp. 751-754

Falguères, C., Bahain, J.J., 2002. La datation par résonance paramagnétique électronique (RPE). In: Miskovsky, J.-C. (Ed.), Géologie de la Préhistoire., Méthodes, Techniques, Applications. Géopré, Seconde édition, pp. 1273-1296.

C. Falguères, Y. Yokoyama, G. Shen, J.L. Bischoff, T.L. Ku, H. Lumley de. New U-series dates at the Caune de l'Arago, France. Journal of Archaeological Science, 31 (2004), pp. 941-952

R. Grün. Electron spin resonance (ESR) dating. Quaternary International, 1 (1989), pp. 65-109

Grün, R., 2005. ESR-DATA, Version: IPH. Unpublished computer program.

R. Grün, O. Katzenberger-Appel. An alpha irradiator for ESR dating. Ancient TL, 12 (1994), pp. 35-38

R. Grifoni, C. Tozzi. L'émergence des identités culturelles au Paléolithique inférieur: le cas de l'Italie. Comptes Rendus Palevol, 5 (2006), pp. 137-148

R. Grün, H.P. Schwarcz, J. Chadam. ESR dating of tooth enamel: coupled correction for U-uptake and U-series disequilibrium. Nuclear tracks, 14 (1988), pp. 237-241

C. Guérin. Les rhinoceros (Mammalia, Perissodactyla) du gisement pléistocène moyen de la caune de l'Arago à Tautavel. Signification stratigraphique. H. Lumley de, J. Labeyrie (Eds.), Absolute dating and Isotope Analysis in Prehistory—Methods and Limits, Prétirage, CNRS, Paris (1981), pp. 163-191

C. Guérin, M. Faure. Biochronologie et datations absolues: convergence des méthodes dans différents sites du Paléolithique ancien. Revue d'Archéométrie, 15 (1991), pp. 41-46

M. Ikeya. A model of linear accumulation of uranium for ESR age of Heidelberg (Mauer) and Tautavel bones. Japanese Journal of Applied Physics, 22 (1982), pp. 763-765

M. Ikeya. New Applications of Electron Spin Resonance—Dating, Dosimetry and Microscopy. World Scientific, Singapore (1993)

M. Ivanovich, R.S. Harmon. Uranium-Series Disequilibrium: Applications to Earth, Marine and Environmental Sciences. (second ed), Clarendon Press, Oxford (1992)

F. Mallegni, F. Bertoldi, E. Carnieri. New Middle Pleistocene human remains from Northern Italy. Homo, 52 (2002), pp. 233-239

Marsh, R., 1999. Beta-gradient isochrons using electron paramagnetic resonance: towards a new dating method in archaeology. Ph.D. Dissertation, McMaster University, Hamilton.

L. Maul, F. Masini, L. Abbazzi, A. Turner. The use of different morphometric dates for absolute age calibration of some South- and Middle-European arvicolid populations. Palaeontographica Italica, 85 (1998), pp. 111-151

A.M. Moigne, M.R. Palombo, V. Belda, D. Heriech-Briki, S. Kacimi, F. Lacombat, M.A. Lumley de, J. Moutoussamy, F. Rivals, J. Quilès, A. Testu. Les faunes de grands mammifères de la Caune de l'Arago (Tautavel) dans le cadre biochronologique des faunes du Pléistocène moyen italien. L'Anthropologie, 110 (2006), pp. 788-831

Palma di Cesnola, A., 1996. Le Paléolithique inferieur et moyen en Italie. Collection “L’Homme des Origines”, No. 1, Série “Préhistoire de l’Europe”, Gérôme Millon, p. 384.
Peretto, C., 1996. I reperti paleontologici del giacimento paleolitico di Isernia la Pineta. L'uomo e l'ambiente. Cosmo Iannone Editore.

J.R. Prescott, J.T. Hutton. Cosmic ray and gamma ray dosimetry for TL and ESR. Nuclear Tracks and Radiation Measurements, 14 (1988), pp. 223-227

J.R. Prescott, J.T. Hutton. Cosmic ray and gamma ray dosimetry for TL and ESR. Nuclear Tracks and Radiation Measurements, 14 (1988), pp. 223-227

M.B. Roberts, C.B. Stringer, S.A. Parfitt. A hominid tibia from Middle Pleistocene sediments at Boxgrove, UK. Nature, 369 (1994), pp. 311-313

A. Segre, A. Ascenzi. Fontana ranuccio: Italy's earliest Middle Pleistocene hominid site. Current Anthropology, 25 (1984), pp. 230-233

Tozzi, C., 1994. Il Paleolitico inferiore e medio del Friuli-Venezia Giulia, Atti XXIX Riun. Scient. Ist. It. Preistoria e Protostoria, pp. 19-36.

Y. Yokoyama, H.V. Nguyen. Direct and non-destructive dating of marine sediments, manganese nodules and corals by high resolution gamma-ray spectrometry. E.D. Goldberg, et al. (Eds.), Isotope Marine Chemistry, Uchida Rokakuho, Tokyo (1980), pp. 259-289

Y. Yokoyama, C. Falguères, J.P. Quaegebeur. ESR dating of quartz from quaternary sediments: first attempt. Nuclear Tracks, 10 (1985), pp. 921-928

Y. Yokoyama, C. Falguères, M.A. Lumley de. Datation directe d'un crâne proto-cro-magnon de qafzeh par la spectrométrie gamma non destructive. Comptes Rendus Académie des Sciences de Paris, 324 (1997), pp. 773-779