Pliocene Early Pleistocene Research Articles

Biogeography of the lizard genus Tropidurus Wied-Neuwied, 1825 (Squamata: Tropiduridae): distribution, endemism, and area relationships in South America.

Based on comprehensive distributional records of the 23 species currently assigned to the lizard genus Tropidurus, we investigated patterns of endemism and area relationships in South America. Two biogeographic methods were applied, Parsimony Analysis of Endemicity (PAE) and Brooks Parsimony Analysis (BPA). Two areas of endemism were detected by PAE: the first within the domains of the semiarid Brazilian Caatinga, which includes seven endemic species, and the second in the region of the Serranía de Huanchaca, eastern Bolivia, in which three endemic species are present. The area cladograms recovered a close relationship between the Atlantic Forest and areas of the South American open corridor. The results revealed a close relationship among the provinces Caatinga (Cerrado, Parana Forest (Pantanal+Chaco)). The uplift of the Brazilian Central Plateau in the Late Pliocene-Early Pleistocene (4-2 Myr BP) has been interpreted as a major event responsible for isolation and differentiation of biotas along these areas. However, we emphasize that without the establishment of a temporal framework concerning the diversification history of Tropidurus it is premature to correlate cladogenetic events with specific time periods or putative vicariant scenarios. The limiting factors hampering the understanding of the biogeographic history of this genus include (1) the absence of temporal references in relation to the diversification of distinct clades within Tropidurus; (2) the lack of an appropriate taxonomic resolution of the species complexes currently represented by widely distributed forms; and (3) the need for a comprehensive phylogenetic hypothesis. We suggest that these three important aspects should be prioritized in future investigations.

Pleistocene vertebrate faunas of the Süttő Travertine Complex (Hungary)

Numerous fossil remains (vertebrates, molluscs and plants) were found in more than twenty sites of the Süttő Travertine Complex during the last 150 years. The majority of these remains were recovered from fissures of the travertine, but also from the travertine and an overlying loess–paleosol sequence. The aims of this study were to review the fossil content, to determine the stratigraphical positions of the various vertebrate faunas of Süttő and provide paleoecological interpretation of the periods on the basis of their faunas and floras. In addition, this paper describes new faunas and floras from the sites Süttő 16–20 and provides 14C dates for Süttő 16.On the basis of the new uranium series isotope and optical dating (OSL), the age of the travertine complex is Middle Pleistocene (235 ± 21–314 ± 45 ka, MIS 7–9), while the age of the loess–paleosol sequence in superposition of the travertine is Middle–Late Pleistocene (MIS 2–MIS 6). In contrast, the fossils of the travertine indicated an older, Pliocene–Early Pleistocene age. A fissure (Süttő 17) and a red clay layer (Süttő 19) contained mammal faunas of Early–Middle Pleistocene age. These results indicated the existence of older travertine in certain quarries (Hegyháti quarry, Cukor quarry).Sedimentological and OSL data of well-dated layers of the loess–paleosol sequence (Süttő/LPS) at Süttő allowed a correlation with the layers of Süttő 6. The paleosol layer in the upper part of the sequence of Süttő 6, was correlated with a pedocomplex of the overlying loess–paleosol sequence, which was dated to MIS 5c (upper, dark soil) and MIS 5e (lower, reddish brown soil). The paleoecological analysis of the mammal and mollusc faunas supported the former interpretation of Novothny et al. (2011) inferring warm, dry climate during the sedimentation of the upper layers, and more humid climate for the lower layers). However, the fauna of the lower soil layer indicated cold climate, so an age of MIS 5d is suggested.Dating of the fissure faunas is based on similarity studies. For some faunas, this method cannot be used, because of the low number of species. On the basis of the species compositions and former interpretations, these faunas originated mainly from sediments that were deposited under cold climatic conditions. Other fissure faunas were dated by AMS 14C (Süttő 16), or by correlation with soil layers of Süttő 6. According to these results, most of the fissure faunas can be correlated with different phases of MIS 5. However, there are a younger (MIS 2) and an older (Early–Middle Pleistocene) fissure fauna also.

Earliest occurrence of Puma pardoides (Owen, 1846) (Carnivora, Felidae) at the Plio/Pleistocene transition in western Europe: New evidence from the Middle Villafranchian assemblage of Montopoli, Italy

The puma-like cat Puma pardoides (Owen, 1846) is reported from several Eurasian localities dated to the Late Pliocene–Early Pleistocene, but its Italian fossil record is really poor; in fact, the only possible occurrence comprises some fragmentary postcranial material from the Late Villafranchian locality of Pirro Nord (1.6–1.3Ma). In the present paper, we describe an isolated left upper carnassial of a medium-sized felid belonging to the collection of fossil mammals from Montopoli (Tuscany, Italy), the type locality of the Middle Villafranchian Faunal Unit (∼2.6 Ma). All the morphological and morphometric characters of the tooth are consistent with an attribution to Puma pardoides (Owen, 1846), which comes out as the second felid species from Montopoli together with Acinonyx pardinensis (Croizet et Jobert, 1828) and is, possibly with the specimens from Perrier-Étouaries, the earliest occurrence in western Europe.

First record of Procyon cancrivorus (G. Cuvier, 1798) (Carnivora, Procyonidae) in stratigraphic context in the Late Pleistocene of Brazil

Although five genera of procyonids are currently present in South America, only two of the extant genera, Procyon and Nasua are represented in the South American fossil record. A recent discovery of a procyonid lower second molar in Late Pleistocene deposits of Aurora do Tocantins, northern Brazil, offers potential to further our understanding of the stratigraphic and temporal range of South American fossil procyonids. We use geometric morphometric analysis of two-dimensional landmarks and semilandmarks to explore morphological variation in the lower second molars of extant Procyon lotor and Procyon cancrivorus and multivariate methods to support the identification of the Pleistocene specimen as P. cancrivorus. This material represents the second fossil record of P. cancrivorus in South America Procyonids entered South America in two phases: the first comprising by Cyonasua and Chapadmalania during the Late Miocene, and the other recent genera, beginning in the Late Pleistocene. These Late Miocene procyonids were more carnivorous than Late Pleistocene-Recent omnivorous taxa and possible went extinct due to competition with other placental carnivorans that entered South America and diversified during the latest Pliocene-Early Pleistocene.

Climate and vegetation in the Upper Valdarno Basin (central Italy) as a response to Northern Hemisphere insolation forcing and regional tectonics in the late Pliocene-early Pleistocene

The pollen record from the Upper Valdarno contributes to the documentation of the main palaeonvironmental changes in one of the best known basins of the Northern Apennines where lacustrine and fluvial sediments deposited since 3.3 Ma. During the Piacenzian the lacustrine system (CSBb of the Castelnuovo dei Sabbioni Synthem) was characterized by the expansion of swamp formations where humid, subtropical to warm temperate forest taxa largely spread. Such assemblages suffer a major decrease under the effect of a gradual cooling since about 2.8 Ma, as testified by the spread of altitudinal coniferous taxa. However, repeated resurgences of subtropical forest taxa have been recorded in the overlain fluvio-deltaic sandy deposits (CSBc), from 2.7 Ma onwards. The first notable expansion of a dry-climate vegetation type consisting of mostly treeless open herbaceous vegetation has been observed in the lower portion of VRC fluvio-lacustrine deposits (Montevarchi Synthem); in fact, the major pulse of Artemisia in the aeolian sands of Rena Bianca is associated to the first glacial cycles that occurred after 2.6 Ma and the tectonic phase that involves the CSB lacustrine deposits.Both climate and tectonics strongly interplay driving the changes in the structure and floral composition of wetlands associated to successive depositional environments. Since 2.6 Ma swamps notably change in structure, with a large reduction of subtropical taxa especially Ta xodium/Glyptostrobus type and the progressive expansion of warm temperate forest taxa. At the same time, marshes expanded with plants able to resist in dynamic environments affected by river action. The palynological documentation of the glacial/interglacial cycles (G/I) younger than 1.7 Ma becomes ever more discontinuous when the effects of tectonics and climate (including the associated interactions) promote successive erosional processes during the emplacement of the lower portion of UFFa (ciottolami di Laterina, Auctt.; Torrente Ciuffenna Synthem). The age of the latter still controversial could fall within an interval of time including the Mid-Pleistocene transition.

Basin evolution in a folding lithosphere: Altai–Sayan and Tien Shan belts in Central Asia

Central Asia is a classical example for continental lithospheric folding. In particular, the Altay–Sayan belt in South-Siberia and the Kyrgyz Tien Shan display a special mode of lithospheric deformation, involving decoupled lithospheric mantle folding and upper crustal folding and faulting. Both areas have a heterogenous crust with a long history of accretion–collision, subsequently reactivated as a far-field effect of the Indian–Eurasian collision. Thanks to the youthfulness of the tectonic deformation in this region (peak deformation in late Pliocene–early Pleistocene), the surface expression of lithospheric deformation is well documented by the surface topography and superficial tectonic structures. A review of the paleostress data and tectono-stratigraphic evolution of the Kurai-Chuya basin in Siberian Altai, Zaisan basin in Kazakh South Altai and Issyk-Kul basin in Kyrgyz Tien Shan suggests that they were initiated in an extensional context and inverted by a combination of fault-controlled deformation and flexural folding. In these basins, fault-controlled deformation alone appears largely insufficient to explain their architecture. Lithospheric buckling inducing surface tilting, uplift and subsidence also played an important role. They form typical basins in a folding lithosphere (FLB). Their characteristic basin fill and symmetry, inner structure, folding wavelength and amplitude, thermal regime, time frame are examined in relation to basement structure, stress field, strain rate, timing of deformation, and compared to existing modelling results.

Femoral neck structure and function in early hominins

All early (Pliocene-Early Pleistocene) hominins exhibit some differences in proximal femoral morphology from modern humans, including a long femoral neck and a low neck-shaft angle. In addition, australopiths (Au. afarensis, Au. africanus, Au. boisei, Paranthropus boisei), but not early Homo, have an "anteroposteriorly compressed" femoral neck and a small femoral head relative to femoral shaft breadth. Superoinferior asymmetry of cortical bone in the femoral neck has been claimed to be human-like in australopiths. In this study, we measured superior and inferior cortical thicknesses at the middle and base of the femoral neck using computed tomography in six Au. africanus and two P. robustus specimens. Cortical asymmetry in the fossils is closer overall to that of modern humans than to apes, although many values are intermediate between humans and apes, or even more ape-like in the midneck. Comparisons of external femoral neck and head dimensions were carried out for a more comprehensive sample of South and East African australopiths (n = 17) and two early Homo specimens. These show that compared with modern humans, femoral neck superoinferior, but not anteroposterior breadth, is larger relative to femoral head breadth in australopiths, but not in early Homo. Both internal and external characteristics of the australopith femoral neck indicate adaptation to relatively increased superoinferior bending loads, compared with both modern humans and early Homo. These observations, and a relatively small femoral head, are consistent with a slightly altered gait pattern in australopiths, involving more lateral deviation of the body center of mass over the stance limb.

Chapter 2 Kinematics of the Aeolian volcanism (Southern Tyrrhenian Sea) from geophysical and geological data

Abstract The Aeolian volcanism ( c. 1 Ma active) develops within the Africa–Eurasia convergence setting, which is characterized by the subduction of the Ionian plate below the Calabrian Arc. Deep earthquakes occur to the east of a tear fault that divides the Aeolian Islands into two sectors: (a) an eastern sector characterized by active volcanism, reduced crustal thickness, high seismic flux, low P-wave velocity (Vp) and attenuation (Qp) and NE–SW extension; (b) a western sector where a NNW–SSE compressive strain along a WNW–ESE-striking fault system is acting. The geophysical and structural features of the eastern sector are consistent with upwelling and SE migration of the asthenospheric mantle. The extensional and strike-slip strain allow the magma to upraise along dyke-like conduits and to erupt. Earthquake-induced strain changes may trigger volcanic eruptions and degassing episodes. The oldest volcanism (Pliocene–Early Pleistocene) was controlled by a WNW–ESE-striking tear fault related to the SE rollback of the slab. A new tear, the Tindari–Letojanni Fault System, started during the Middle–Late Pleistocene and represents the active western boundary of the subducting slab. The present-day Aeolian volcanism is associated with rifting processes developing within an arc collision zone.

La Désirade island (Guadeloupe, French West Indies): a key target for deciphering the role of reactivated tectonic structures in Lesser Antilles arc building

Abstract In this paper we present and discuss new investigations performed on both the magmatic basement and the sedimentary formations of La Désirade. We report structural and sedimentary evidences for several episodes of deformation and displacement occurring prior to the present day tectonics. The main faults, respectively N130 ± 10°, N040 ± 10° and N090 ± 10°, previously considered as marker of the current tectonic regime corresponds to reactivated tectonic structures developed first during late Cretaceous compression and second during Pliocene to early Pleistocene extension. We demonstrate also the importance of late Pliocene-early Pleistocene and middle-late Pleistocene vertical movements in this part of the Lesser Antilles fore-arc as well as the role of compressive tectonics in the over thickened character of the arc basement in the Guadeloupe archipelago.

Photosynthetic efficiency and quantitative reaction of bread winter wheat to mild short-terms drought conditions

Geochemical and mineralogical studies of palaeosols provide essential information for palaeoclimatic and palaeoenvironmental interpretation of continental deposits and can present a proxy for palaeoclimate. Red clays in the central Carpathian Basin (Hungary) (Tengelic Red Clay Formation; Kerecsend Red Clay Formation), overlain by loess-palaeosol sequences, were studied. Results from geochemical climofunctions applied to Upper Pliocene–Lower Pleistocene red clays and palaeosols located in the Carpathian Basin, and clay mineralogy, indicate that the palaeoclimate was considerably more humid and warmer during the Late Pliocene-Early Pleistocene in comparison to modern values.

Size Analysis of the Late Pliocene-Early Pleistocene Upper Siwalik Sediments, Northwestern Himalaya, India

Size analysis of the Late Pliocene-Early Pleistocene Upper Siwalik sediments comprising the Pinjor Formation in the type area and adjoining regions reveals that the sediments are bimodal to polymodal in nature, medium to fine grained and are moderately sorted. The inclusive graphic standard deviation and moment standard deviation values suggest the deposition of sediments in shallow to moderately deep fluvial agitated water. The log probability plots reveal that saltation mode is the dominant mode of transportation of detritus. The sediments are continental in character and are derived from crystalline, metamorphic and sedimentary rocks of the Himalaya exposed to the North of the type area Pinjor.

Clay mineralogy of red clay deposits from the central Carpathian Basin (Hungary): implications for Plio-Pleistocene chemical weathering and palaeoclimate

Geochemical and mineralogical studies of palaeosols provide essential information for palaeoclimatic and palaeoenvironmental interpretation of continental deposits and can present a proxy for palaeoclimate. Red clays in the central Carpathian Basin (Hungary) (Tengelic Red Clay Formation; Kerecsend Red Clay Formation), overlain by loess-palaeosol sequences, were studied. Results from geochemical climofunctions applied to Upper Pliocene–Lower Pleistocene red clays and palaeosols located in the Carpathian Basin, and clay mineralogy, indicate that the palaeoclimate was considerably more humid and warmer during the Late Pliocene-Early Pleistocene in comparison to modern values.

Annually resolved temperature reconstructions from a late Pliocene–early Pleistocene polar forest on Bylot Island, Canada

Here we use δ18O ratios measured in tree rings of crossdated sub-fossil wood to reconstruct an annually resolved record of temperature and δ18O of meteoric water for an interglacial late Pliocene–early Pleistocene fossil forest found on Bylot Island, Nunavut, Canada. Our record represents the first crossdated record of Pliocene wood. Mean annual temperatures determined in this study average −3.4±3.8°C, which is 11.4±4.4°C warmer than present-day Bylot Island (−14.8±2.2°C). June–July temperatures average 13.5±1.1°C, approximately 12.6±1.6°C warmer than present-day. Meteoric water δ18O values average −15.5±2.9‰, ~2–6‰ more enriched than present values of precipitation δ18O. Our temperatures are comparable to mid-Pliocene modeled temperatures for the Arctic (3–5°C warmer than present), suggesting that interglacial warm periods in the late Pliocene–early Pleistocene may have been as warm as the mid-Pliocene warm period. That both the Bylot Island forest deposit and the Kap København deposit represent the remains of northern tree-line vegetation that lived during warm interglacial periods within the overall cool Plio-Pleistocene suggests that forest deposits in the Arctic capture a snapshot of interglacial conditions during the Plio-Pleistocene rather than the average Pliocene climate and may not be suitable records to study Pliocene cooling.

Towards a new orbital tuning for the late Pliocene-early Pleistocene marine cores

Towards a new orbital tuning for the late Pliocene-early Pleistocene marine cores

Cenozoic tectonics and evolution of the Euphrates valley in Syria

Abstract Late Cenozoic tectonics affected the evolution of the Euphrates river valley in northern Syria. Data on the height and composition of terraces and new K–Ar dating of overlying basalts are presented for the area between the Assad Reservoir and the town of Abou Kamal. The presence of the Late Cenozoic Euphrates Fault, longitudinal with respect to the valley, is established by the lower height of the terraces on the NE side of the valley compared with the same terraces on the SW side. Geophysical profiling (dipole axial sounding; correlation refraction method and georadar) across the southern side of the valley (opposite the town of Ar Raqqa) confirms the offset on the fault as >25 m. Movements along the transverse Rasafeh–El Faid fault zone and the Halabiyeh–Zalabiyeh deformation zone have resulted in local uplift and the splitting of river terraces. During the Pliocene–Early Pleistocene, uplift and strong incision of the Euphrates valley propagated from near the Syrian–Turkish border to near the Iraq–Syrian border. The Euphrates began to deposit alluvium onto the pre-existing low-lying Mesopotamian Foredeep at c. 3.5 Ma. Intense incision began by late Late-Pliocene time to form terrace IV. Comparable incision further downstream began during the Early Pleistocene to form terrace III.

Phylogeography of the Crown-of-Thorns Starfish in the Indian Ocean

BackgroundUnderstanding the limits and population dynamics of closely related sibling species in the marine realm is particularly relevant in organisms that require management. The crown-of-thorns starfish Acanthaster planci, recently shown to be a species complex of at least four closely related species, is a coral predator infamous for its outbreaks that have devastated reefs throughout much of its Indo-Pacific distribution.Methodology/Principal FindingsIn this first Indian Ocean-wide genetic study of a marine organism we investigated the genetic structure and inferred the paleohistory of the two Indian Ocean sister-species of Acanthaster planci using mitochondrial DNA sequence analyses. We suggest that the first of two main diversification events led to the formation of a Southern and Northern Indian Ocean sister-species in the late Pliocene-early Pleistocene. The second led to the formation of two internal clades within each species around the onset of the last interglacial. The subsequent demographic history of the two lineages strongly differed, the Southern Indian Ocean sister-species showing a signature of recent population expansion and hardly any regional structure, whereas the Northern Indian Ocean sister-species apparently maintained a constant size with highly differentiated regional groupings that were asymmetrically connected by gene flow.Conclusions/SignificancePast and present surface circulation patterns in conjunction with ocean primary productivity were identified as the processes most likely to have shaped the genetic structure between and within the two Indian Ocean lineages. This knowledge will help to understand the biological or ecological differences of the two sibling species and therefore aid in developing strategies to manage population outbreaks of this coral predator in the Indian Ocean.

Rock-magnetic cyclostratigraphy for the Late Pliocene–Early Pleistocene Stirone section, Northern Apennine mountain front, Italy

Abstract Lithostratigraphic, magnetostratigraphic and rock-magnetic cyclostratigraphic data were combined to create a high-resolution age model for 342 m of Late Pliocene–Middle Pleistocene marine deposits exposed in the Stirone River, northern Italy. Magnetostratigraphic analysis of 74 oriented samples at 21 stratigraphic horizons recognized five polarity zones between c. 3.0 and 1.0 Ma. Unoriented samples were collected every metre between 0 and 311 m and low-field magnetic susceptibility ( χ ) was measured for cyclostratigraphic analysis. The χ data series was tied to absolute time using the magnetostratigraphy and subjected to multi-taper method spectral analysis. The resultant power spectra revealed significant frequency peaks that are aligned with eccentricity, obliquity and precession Milankovitch orbital cycles. The χ data, correlated to the 41 ka obliquity and the 23 ka/19 ka precession cycles and anchored to a well-established biostratigraphic horizon, were used to create a high-resolution age model for the Stirone section between 2.99 and 1.81 Ma, where stratigraphic positions of magnetic reversals were previously poorly defined. This cyclostratigraphic age model reveals that the length of an important depositional hiatus at the base of the C2An.1n subchron is 200 ka shorter than previously determined. We link the precession-aligned variability in χ to global mid-latitude, insolation-induced variability in runoff and ocean circulation.

A diatom record of late Pliocene cooling from the Ross Sea continental shelf, AND-1B, Antarctica

A late Pliocene – early Pleistocene, 2.9–2.0Ma, diatom record from the Antarctic Geological Drilling Program (ANDRILL) MIS drillcore AND-1B is presented. This core, recovered from beneath the Ross Ice Shelf south of Ross Island, comprises multiple diatomaceous-sediment units deposited during interglacial periods with open water over the core site. These represent interglacial phases of orbitally paced climate cycles and are punctuated by glacial advances. Extant diatom assemblages have limited presence in the late Pliocene record, which makes environmental interpretation less straight forward. We employ modern ecological data in combination with late Pliocene to present variation in diatom assemblages across the Southern Ocean oceanic fronts based on DSDP/ODP diatom biostratigraphic data to evaluate paleoenvironmental change for the 2.9–2.0Ma interval of the AND-1B core. The diatom assemblages from AND-1B record a progressive environmental change through the late Pliocene–early Pleistocene. A relatively warm period with potential SST of up to 4°C at ca. 2.9Ma was succeeded by a reduction of warm water species and an increase of taxa associated with more southerly water masses until 2.58Ma (at isotope stage G1). Younger, early Pleistocene, diatomaceous units are dominated by extinct Rouxia, Thalassiosira species and newly described Fragilariopsis species indicative of cold open water and drift ice. The last recorded cooling step occurs at the top of the interval studied (ca 2.0) Ma indicated by the trace abundance of Fragilariopsis and Actinocyclus species present in modern sea ice assemblages but absent in the late Pliocene–early Pleistocene AND-1B record, even though many of its species had their first occurrences during the Pliocene. The extant sea ice assemblage occurs with an abundance of 2–29% (average 10%) in the late Pliocene–early Pleistocene AND-1B record implying that the modern sea ice and ice shelf polar conditions were not established within the studied interval. The most frequently applied sea ice indicator, Fragilariopsis curta, is consistently present in low to moderate abundance (1–22%) together with Chaetoceros resting spores (2–30%) through the 2.9–2.0Ma interval. The diatom assemblage shifts indicate a dynamic environment with an overall trend towards colder conditions after ca. 2.6Ma but does not reach the Holocene configuration.

Structural characteristics and tectonic evolution of the northwestern margin of the Nile Delta, Egypt

The Interference between the northeast, East–West, and northwest oriented faults imposed a complex structural setting of the northwestern margin of the Nile Delta, Northeast Africa. The pre-existing faults were reactivated during the evolution of the Nile Delta by two tectonic events. These events took place during the Late Miocene–Early Pliocene and Late Pliocene–Early Pleistocene times and were coeval with two falls in the sea level pattern. Some of these faults have continued to affect the bottom sea sediments and increased the northerly slope of the upper surface of the delta body. The thickness of the Pliocene-Recent sediments and the location of the pre-existing faults controlled these reactivations. The mechanical contrast of these sediments and fault displacements controlled the geometry of the reactivated faults. The rotated displacement on some of these faults is associated with growth units upward. The northwest sinking (bending) of the outer part of the African continental margin under the Eurasian plate at the Hellenic subduction Arc has induced a tangential northwest trending extension (an average of N37°W–S37°E trend) in the outer zone of the northern African margin that is responsible mainly for the reactivations of the pre-existing faults.

Preliminary results of combined ESR/U-series dating of fossil teeth from Longgupo cave, China

Longgupo Cave site, located in Wushan County, Chongqing, China has attracted continuous attention since its discovery of hominid remains in association with late Pliocene-early Pleistocene fauna and numerous lithic artefacts. In 2003–2006, new excavation was carried out on this site, allowing the description of a detailed stratigraphy of the highly complex cave infillings and the sampling of teeth for combined ESR/U-series analyses. Here we report preliminary dating results of seven herbivorous fossil teeth from different archaeological layers of the lowest geological unit (C III). Uranium-series analyses indicate that no obvious uranium leaching has occurred and all the teeth (except one) underwent a very recent uranium uptake history. The obtained US-ESR results show that the age of six teeth are basically consistent, between ∼1.4 and 1.8 Ma. At the same time, we observed an inverse correlation of two samples with the stratigraphical sequence. This could be caused by the distinct uranium uptake history of one sample, high uranium content in the enamel for another or bad estimation of external dose rate. Due to the complexity of the stratigraphic sequence, supplementary in situ gamma dose rate measurement should be performed for all the samples during the following excavations in order to confirm this preliminary ESR/U-series chronology.