Western Pyrenees Research Articles

Circulation of whale-bone artifacts in the northern Pyrenees during the late Upper Paleolithic

The importance of coastal resources in the late Upper Paleolithic of western Europe has been reevaluated in recent years thanks to a growing body of new archeological evidence, including the identification of more than 50 implements made of whale bone in the Magdalenian level of the Isturitz cave (western Pyrenees). In the present study, the assemblages of osseous industry from 23 Magdalenian sites and site clusters in the northern Pyrenees were investigated, systematically searching for whale-bone implements. The objective of this research was to determine if, and how, tools and weapons of coastal origin were circulated beyond Isturitz into the inland, and if similar implements existed on the eastern, Mediterranean side of the Pyrenees. A total of 109 whale-bone artifacts, mostly projectile heads of large dimensions, were identified in 11 sites. Their geographic distribution shows that whale bone in the Pyrenean Magdalenian is exclusively of Atlantic origin, and that objects made of this material were transported along the Pyrenees up to the central part of the range at travel distances of at least 350 km from the seashore. This phenomenon seems to have taken place during the second half of the Middle Magdalenian and the first half of the Late Magdalenian, ca. 17,500–15,000 cal BP (calibrated years before present). The existence of a durable, extended coastal-inland interaction network including the circulation of regular tools is thus demonstrated. Additionally, differences between the whale-bone projectile heads of the Middle Magdalenian and those of the Late Magdalenian document an evolutionary process in the design of hunting weapons.

Thermal history of the Aragón-Béarn basin (Late Paleozoic, western Pyrenees, Spain); insights into basin tectonic evolution

Organic and inorganic thermal indicators throughout the Late Paleozoic sedimentary fill of the Aragon-Bearn Basin in the western Pyrenees, integrated with stratigraphic and structural data, point to a two-stage tectonic evolution:(i) High heat flow values and widespread magmatic intrusions driven by deeply rooted strike-slip faults characterized the first stage. This regime accompanied the rapid and localized deposition of the lower sedimentary succession and ended with uplift and erosion.(ii) The second stage was characterized by lower heat flow values, shallower strike-slip faults active during the deposition of an upper transgressive sedimentary succession and minor magmatic intrusions.The lower portion of the succession (Unidad Gris, Unidad de Transito and Unidad Roja Inferior, mainly Stephanian-Early Permian in age) records maximum temperatures between 170°C and 220°C as shown by clay mineral-based geothermometers (KI between 0.40 and 0.52°?2?, conversion of mixed layer illite-smectite to discrete illite), vitrinite reflectance (about 2.5%), and total homogenization temperatures from host-rock quartz cements between 160 and 180°C.The upper portion of the succession (Unidad Roja Superior, mainly Upper Permian in age) records maximum temperatures between 100-110° and 150°C as indicated by KI values between 0.57 and 0.94°?2?, illite content in mixed layer illite-smectite of 85-92%, and fluid inclusions in host-rock quartz-calcite cements.Local thermal maturity anomalies affected selected portions of the Late Paleozoic sedimentary succession with organic matter and clay minerals reaching respectively Ro%: 4.2-4.7% and KI up to 0.32°?2??in the lower sequence, and Ro% 2.9% in the upper sequence. These localized anomalies with respect to the basin thermal signature are the result of contact metamorphism related to the emplacement of magmatic intrusions across the sedimentary fill during two different magmatic events.

Microgastrinae (Hymenoptera: Braconidae) in the Forest State of Artikutza (Navarra: Spain): Diversity and Community Structure.

Microgastrinae is one of the largest subfamilies of the Braconidae with about 2,000 described species worldwide. These wasps are of enormous ecological interest due to their role in controlling the caterpillar populations. This study analyses diversity and community structure within the Microgastrinae in the Artikutza Forest, located in the Peñas de Aia Natural Park, western Pyrenees, Spain. The specimens were collected in two different habitats: mixed forest and beech forest. A total of 524 specimens, belonging to nine separate genera and 27 species were captured. Alpha, beta and gamma diversity were analyzed. Additionally, the relationship between Microgastrinae phenology and climatic conditions were studied.

Spatial variations of seismic attenuation and heterogeneity in the Pyrenees: Coda Q and peak delay time analysis

Abstract Lateral variations of seismic attenuation in the Pyrenees are explored from the analysis of local earthquake records. Scattering loss and intrinsic absorption both control the propagation of short period S waves through the crust. The role of intrinsic and scattering attenuation is analyzed in two steps. Firstly, the coda quality factor Q c , which quantifies the energy decay of coda waves, is estimated at large lapse time in five frequency bands and interpreted as intrinsic absorption. Next, we systematically measure the peak delay time defined as the time lag from the direct S-wave onset to the maximum amplitude arrival. This parameter quantifies the strength of multiple forward scattering due to random inhomogeneities along the seismic ray path. Comparison of coda- Q and peak delay time measurements allows a qualitative interpretation of the origin of seismic attenuation (scattering/absorption) in the Pyrenean crust. At low frequency, coda- Q variations mainly depend on the tectonic units of the Pyrenees, with stronger absorption in sedimentary basins and smaller absorption in Paleozoic basements. At high frequency, coda- Q is low at the location of Neogene structures in the Eastern Pyrenees. A more enigmatic low- Q c anomaly is also observed at the location of the Maladeta Massif in the Central Pyrenees. In all frequency bands, peak delay time measurements systematically show stronger scattering in the Western Pyrenees. In the Labourd–Mauleon area, absorption and scattering are both important at low frequency. The Western Pyrenees also correspond to a high-velocity/density anomaly revealed from tomography and gravity data analysis. This suggests that the high level of inhomogeneities and absorption may be related to intrusion of mantle and/or lower-crustal materials. In the Eastern Pyrenees, absorption appears dominant over scattering at high frequency. We hypothesize that the strong absorption observed in this area may be related to volcanic structures.

The Ainsa Fold and thrust oblique zone of the central Pyrenees: Kinematics of a curved contractional system from paleomagnetic and structural data

AbstractIntegration of structural, stratigraphic, and paleomagnetic data from the N–S trending structures of the Ainsa Oblique Zone reveals the kinematics of the major thrust salient in the central Pyrenees. These structures experienced clockwise vertical axis rotations that vary from 70° in the east (Mediano anticline) to 55° in the west (Boltaña anticline). Clockwise vertical axis rotations of 60° to 45° occurred from early Lutetian to late Bartonian when the folds and thrusts of the Ainsa Oblique Zone developed. This vertical axis rotation stage resulted from a difference of about 50 km in the amount of displacement on the Gavarnie thrust and an accompanying change in structural style at crustal scale from the central to the western Pyrenees, related to the NE–SW trending pinch out of Triassic evaporites at its basal detachment. A second rotation event of at least 10° took place since Priabonian, as a result of a greater displacement of the Serres Marginals thrust sheet with respect to the Gavarnie thrust sheet above the Upper Eocene‐Oligocene salts. The deduced kinematics demonstrates that the orogenic curvature of the central Pyrenees is a progressive curvature resulting from divergent thrust transport direction. Layer parallel shortening mesostructures and kilometer‐scale folds also developed by a progressive curvature related to divergent shortening directions during vertical axis rotation. Rotation space problems were solved by along‐strike extension which triggered the formation of transverse extensional faults and diapirs at the outer arcs of structural bends.

The larva of Drusus vinconi Sipahiler, 1992 (Trichoptera, Limnephilidae, Drusinae)

This paper describes the previously unknown larva of Drusus vinconi Sipahiler, 1992. Information on the morphology of the 5th larval instar is given, and the most important diagnostic features are illustrated. In the context of existing identification keys the larva of Drusus vinconi keys together with Drusus annulatus (Stephens, 1837), Drusus biguttatus (Pictet, 1834), Drusus ingridae Sipahiler, 1993, Hadimina torosensis Sipahiler, 2002 and Leptodrusus budtzi (Ulmer, 1913). These species differ in the contours of the pronotum in lateral view, the presence/absence of the pronotal transverse groove, the shape of the median notch of the pronotum (in anterior view), pronotal sculpturing, presence/absence of the lateral carina of the head capsule, the number of proximo-dorsal setae on the mid-and hind femora, where the lateral fringe starts on the abdomen, and in geographic distribution. With respect to zoogeography, Drusus vinconi is a (micro-)endemic of the Western Pyrenees. The species prefers stony substratum in springs and springbrooks of the montane and subalpine region (Graf et al. 2008; Sipahiler 1992, 1993). As a grazer, the larvae of Drusus vinconi feed on biofilm and epilithic algae.

Discovery of a new blind ground beetle in western French Pyrenees, and its relevance to the phylogeny of Pyrenean hypogean Trechini.

Geotrechus sarpedon sp. n., a new species of blind Trechini is described from Arbailles Massif, western Pyrenees, trance. The generic attribution of the new species was challenging as it shares morphological features of both genera Geotrechus Jeannel, 1919 and Aphaenops subgenus Hydraphaenops Jeannel, 1926, confirming their polyphyly, which has been highlighted by previous molecular studies on the group. Molecular data suggests unambiguously strong affinities between the new species and the clade Aphaenops vasconicus Jeannel, 1913-A. galani Espanol, 1968 occurring in the same geographic area, and not related with Aphaenops ehlersi (Abeille de Perrin, 1872), type species of the subgenus Hydraphaenops. The species is included in the paraphyletic genus Geotrechus until its affinities with the other species of Geotrechus and A. (Hydraphaenops) are clarified.

Assessing changes in species distribution from sequential large-scale forest inventories

It is assumed that global change is already affecting the composition, structure and distribution of forest ecosystems; however, detailed evidences of altitudinal and latitudinal shifts are still scarce. To develop a method based on National Forest Inventory (NFI) to assess spatio-temporal changes in species distributions. We develop an approach based on universal kriging to compare species distribution models from the different NFI cycles and regardless of the differences in the sampling schemes used. Furthermore, a confidence interval approach is used to assess significant changes in species distribution. The approach is applied to some of the southernmost populations of Pinus sylvestris and Fagus sylvatica in the Western Pyrenees over the last 40 years. An increase of the presence of the two species in the region was observed. Scots pine distribution has shifted about 1.5 km northwards over recent decades, whereas the European beech has extended its distribution southwards by about 2 km. Furthermore, the optimum altitude for both species has risen by about 200 m. As a result, the zone in which the two species coexist has been enlarged. This approach provides a useful tool to compare NFI data from different sampling schemes, quantifying and testing significant shifts in tree species distribution over recent decades across geographical gradients.

Ophicalcites from the northern Pyrenean belt: a field, petrographic and stable isotope study

Brecciated and fractured peridotites with a carbonate matrix, referred to as ophicalcites, are common features of mantle rocks exhumed in passive margins and mid-oceanic ridges. Ophicalcites have been found in close association with massive peridotites, which form the numerous ultramafic bodies scattered along the North Pyrenean Zone (NPZ), on the northern flank of the Pyrenean belt. We present the first field, textural and stable isotopic characterization of these rocks. Our observations show that Pyrenean ophicalcites belong to three main types: (1) a wide variety of breccias composed of sorted or unsorted millimeter- to meter-sized clasts of fresh or oxidized ultramafic material, in a fine-grained calcitic matrix; (2) calcitic veins penetrating into fractured serpentine and fresh peridotite; and (3) pervasive substitution of serpentine minerals by calcite. Stable isotopic analyses (O, C) have been conducted on the carbonate matrix, veins and clasts of samples from 12 Pyrenean ultramafic bodies. We show that the Pyrenean ophicalcites are the product of three distinct genetic processes: (1) pervasive ophicalcite resulting from relatively deep and hot hydrothermal activity; (2) ophicalcites in veins resulting from tectonic fracturing and cooler hydrothermal activity; and (3) polymictic breccias resulting from sedimentary processes occurring after the exposure of subcontinental mantle as portions of the floor of basins which opened during the mid-Cretaceous. We highlight a major difference between the eastern and western Pyrenean ophicalcites belonging, respectively, to the sedimentary and to the hydrothermal types. Our data set points to a possible origin of the sedimentary ophicalcites in continental endorheic basins, but a post-depositional evolution by circulation of metamorphic fluids or an origin from relatively warm marine waters cannot be ruled out. Finally, we discuss the significance of such discrepancy in the characteristics of the NPZ ophicalcites in the frame of the variable exhumation history of the peridotites all along the Pyrenean realm.

An Exceptional Rainfall Event in the Central Western Pyrenees: Spatial Patterns in Discharge and Impact

AbstractAn exceptional rainfall and hydrological event occurred on 19–21 October 2012 in the central western Pyrenees and was particularly significant in the Upper Aragón River basin and its tributaries, mainly the Irati River. Analysis of historical records showed that, considered separately, the event of 19 and 20 October ranked between the second and fifth highest most extreme daily precipitation events. For the two days combined (with a total between 200 and 260 mm), the precipitation event was the most extreme 2‐day event among all observation stations but one. The consequent flood destroyed part of an urban area, and a long stretch of a national road triggered landslides, enlarged the alluvial plain and caused generalised soil erosion in cultivated fields cropped with winter cereals. Badlands in the marls of the Inner Depression yielded high volumes of sediment. The floods in the tributaries were relatively moderate (return periods of 14–42 years), whereas in the Upper Aragón River, the flood corresponded to a return period of approximately 400–500 years and to 142 years at the end of the Yesa reservoir, although difficulties in estimating the discharge increased the uncertainty of these values. The Yesa and Itoiz reservoirs considerably reduced the intensity of the flood in the middle and lower Aragón River and confirmed the importance of the water level in the reservoirs when such rainfall events occur. The water storage in the Yesa reservoir increased from 16% to 53% as a consequence of the event. More integrated studies are necessary to decrease the risks associated with flood hazards. This is particularly the case in mountain areas, where the steep slopes and longitudinal gradients of the rivers shorten the concentration time of floods and increase the energy that erodes channels and riverbanks. Copyright © 2013 John Wiley & Sons, Ltd.

Albian syndepositional block rotation and its geological consequences, Basque–Cantabrian Basin (western Pyrenees)

AbstractStratigraphic, structural, palaeocurrent and palaeomagnetic analyses of Upper Albian deep-water deposits in and around the Deba block (Northern Iberia) are presented. Results indicate an anticlockwise vertical-axis rotation of this block by 35° during a maximum time span of c. 1 Ma (Late Albian intra-C. auritus ammonite Subzone). This Albian syndepositional block rotation is interpreted to be the consequence of the coeval activity of conjugate major sinistral strike-slip faults and minor (antithetic) dextral strike-slip faults, which border the Deba block. On the base of conservative estimations, a minimum block-rotation rate of 35° Ma−1 and a sinistral strike-slip rate of 1.2 km Ma−1 are calculated. As a consequence of the interaction of the rotated Deba block with adjacent non-rotated blocks, its corners experienced coeval transpressive (NW and SE corners) and transtensional deformations (SW and, possibly, NE corners). At the transtensional SW corner, two domal high-reflective seismic structures have been recorded and interpreted as high-level magmatic laccoliths. These magmatic intrusions triggered the development of a mineralizing hydrothermal system, which vented to the Late Albian seafloor warm to hot hydrocarbon-rich fluids. Vented hydrocarbon was generated from Albian organic-rich sediments by contact alteration with hydrothermal fluids.

Syn‐depositional thin‐ and thick‐skinned extensional tectonics in the mid‐Cretaceous Lasarte sub‐basin, western Pyrenees

AbstractIn the mid‐Cretaceous Lasarte sub‐basin (LSB) [northeastern Basque‐Cantabrian Basin (BCB)] contemporaneous and syn‐depositional thin‐ and thick‐skinned extensional tectonics occur due to the presence of a ductile detachment layer that decoupled the extension. Despite the interest in extension modes of rift basins bearing intra‐stratal detachment layers, complex cases remain poorly understood. In the LSB, field results based on mapping, stratigraphic, sedimentological and structural data show the relationship between growth strata and tectonic structures. Syn‐depositional extensional listric faults and associated folds and faults have been identified in the supra‐detachment thin‐skinned system. But stratigraphic data also indicate the activation of sub‐detachment thick‐skinned extensional faults coeval with the development of the thin‐skinned system. The tectono‐sedimentary evolution of the LSB, since the Late Aptian until the earliest Late Albian, has been interpreted based on thin‐ and thick‐skinned extensional growth structures, which are fossilized by post‐extensional strata. The development of the thin‐skinned system is attributed to the presence of a ductile detachment layer (Upper Triassic Keuper facies) which decoupled the extension from deeper sub‐detachment basement‐involved faulting under a regional extensional/transtensional regime.

Intrinsic vulnerability mapping for small mountainous karst aquifers, implementation of the new PaPRIKa method to Western Pyrenees (France)

The new intrinsic vulnerability mapping method PaPRIKa is proposed as a tool to assess groundwater protection of small karst systems exploited for drinking water supply purposes in the French Pyrenees. The specific characteristics of the discontinuous carbonate aquifers of mountainous areas are here considered and taken into account into the implementation of the methodology. The Orbe site from the French Western Pyrenees area is chosen as a test site because of the relatively well known structure and behavior of the aquifer system. Steep slopes, extremely developed dissolution features, thin soils and strong dipping of geological formations are the main points to be considered. PaPRIKa method appears as a tool to assess and illustrate both the resource and source vulnerability according to the site specificities provided that appropriate field observations at a relatively high density are carried out. The vulnerability of the resource was assessed for the entire catchment area, while source-orientated mapping was attempted for the catchment area of the main capture work used for drinking water supply.

Dissemination of genetic progress: a key aspect of genetic improvement of local breeds

Researches on local breeds have mainly focused on the scientific and technical activities of genetic gain production and/or maintain genetic variability. The diffusion of the genetic gain used to be taken for granted, or considered as of little importance as the State was subsidizing official breeding schemes. However, diffusion and sustainability of small local-breeding schemes are threatened by current changes in breeding activities and organizations. Diversification of farming and breeding objectives, liberalization of public policies on breeding activities, decrease in public support change the business model of breeding organizations. Local breeds are particularly concerned, as they may be threatened by more competitive and widespread ones. Indeed, the management of the diffusion dimension of breeding activities gets a greater importance. Thus, there is a need for a better understanding of the market of genetic gain and the strategies of its participants. To investigate this issue, we study with quantitative and qualitative data, the way the genetic market works in the case of local dairy sheep breeds in the Western Pyrenees. In this area, the use of artificial insemination (AI) outside nucleus flocks is weak. The diffusion is mainly based on the exchanges of live breeding animals, but the number and substance of the exchanges are unknown. We analyse two types of markets, which are set up: the official sale of breeding animals, organized by the breeding centre; the parallel market of rams' exchanges by mutual agreement between farmers. We find several paradoxical results: the more expensive animals are sold outside of the breeding schemes, while the genetic value is more uncertain; the breeding centre does not find enough buyers for its rams, while there is a shortage of rams in the region; outside the breeding schemes, the parallel market of rams is dominant. We also identify that there is a diversity of prices on the market, which cannot be explained based on the scientific evaluation of animals. We show the existence of a second-hand market of rams. In conclusion, we argue that there are various ways of managing the diffusion of genetic gain, and that the market is only one of this.

Errakina: Pastoral Fire Use and Landscape Memory In the Basque Region of the French Western Pyrenees

People in the French Western Pyrenees have used fire for millennia in order to shape and manage landscapes. This history has left cultural and ecological legacies that both reflect and ensure the relative persistence of landscape patterns and processes. In this paper I draw on ethnographic research, ethnohistorical evidence, and Bayesian spatial analyses of historical fire use locations and land use maps to shed some light on human-firelandscape dynamics in the Pyrenees for the years 1830 to 2011. I show how cultural and ecological legacies reflect a self-organized fire management regime that emerges from fire use driven by the production goals of individual households. I frame the self-organizing dynamic inherent in Pyrenean pastoral fire use as ‘‘landscape memory.’’ This conclusion has implications for the future direction of fire-related conservation policy for the Pyrenees and for analogous systems characterized by self-organized land management regimes.

Sponges and corals from the Middle Eocene (Bartonian) marly formations of the Pamplona Basin (Navarre, western Pyrenees): taphonomy, taxonomy, and paleoenvironments

Sponges and corals from the Bartonian marly formations of the Pamplona Basin (South Pyrenean area, Navarre) are described for the first time. The fossiliferous levels correspond respectively to flood-influenced delta-front (Ardanatz Sandstone) and restricted outer-platform (Ilundain Marls Fm.) environments. The fossil sponges exhibit diagenetic fragmentation, but they are often complete specimens. The skeleton appears partially or totally replaced by calcite and/or in some cases large crystals of celestite. Celestite forms relatively early during diagenesis in a dysoxic environment. Neomorphic fibrous quartzine-lutecine spherulites are also present. Hexactinellids and lithistids occur, but the former predominate. The associations include the species Laocoetis samueli, Guettardiscyphia thiolati and/or Pleuroguettardia iberica, cf. Rhizocheton robustus, and two lithistids indet. Corals are present only in the Ardanatz Sandstone. The fossil skeletons are composed of large neomorphic sparry calcite crystals. The assigned species are Stylocoenia taurinensis, Astrocoenia octopartita, Ceratotrochus bodellei, Placosmiliopsis bilobatus, and Desmophyllum castellolense. The sponge and coral taxa are similar to those previously described from other contemporaneous geological formations of the Pyrenean realm. The Pamplona Basin assemblages appear less diverse than those of the Bartonian of the eastern South Pyrenean area, more similar to that of the Eocene of Biarritz (Aquitanian Basin). This lower diversity is not due to a lower-resolution sampling but to taphonomic bias and/or paleoecological differences. The dominance of hexactinellids, erect morphologies, and sedimentological and micropaleontological data show that the sponge communities lived in deep shelfal waters. The corals, mainly associated with levels with high terrigenous content, seem reworked from shallower and more proximal environments.

Multilocus phylogeography of the common lizard Zootoca vivipara at the Ibero-Pyrenean suture zone reveals lowland barriers and high-elevation introgression.

BackgroundThe geographic distribution of evolutionary lineages and the patterns of gene flow upon secondary contact provide insight into the process of divergence and speciation. We explore the evolutionary history of the common lizard Zootoca vivipara (= Lacerta vivipara) in the Iberian Peninsula and test the role of the Pyrenees and the Cantabrian Mountains in restricting gene flow and driving lineage isolation and divergence. We also assess patterns of introgression among lineages upon secondary contact, and test for the role of high-elevation trans-mountain colonisations in explaining spatial patterns of genetic diversity. We use mtDNA sequence data and genome-wide AFLP loci to reconstruct phylogenetic relationships among lineages, and measure genetic structure.ResultsThe main genetic split in mtDNA corresponds generally to the French and Spanish sides of the Pyrenees as previously reported, in contrast to genome-wide AFLP data, which show a major division between NW Spain and the rest. Both types of markers support the existence of four distinct and geographically congruent genetic groups, which are consistent with major topographic barriers. Both datasets reveal the presence of three independent contact zones between lineages in the Pyrenean region, one in the Basque lowlands, one in the low-elevation mountains of the western Pyrenees, and one in the French side of the central Pyrenees. The latter shows genetic evidence of a recent, high-altitude trans-Pyrenean incursion from Spain into France.ConclusionsThe distribution and age of major lineages is consistent with a Pleistocene origin and a role for both the Pyrenees and the Cantabrian Mountains in driving isolation and differentiation of Z. vivipara lineages at large geographic scales. However, mountain ranges are not always effective barriers to dispersal, and have not prevented a recent high-elevation trans-Pyrenean incursion that has led to asymmetrical introgression among divergent lineages. Cytonuclear discordance in patterns of genetic structure and introgression at contact zones suggests selection may be involved at various scales. Suture zones are important areas for the study of lineage formation and speciation, and our results show that biogeographic barriers can yield markedly different phylogeographic patterns in different vertebrate and invertebrate taxa.

Datation radiocarbone directe et attribution culturelle des vestiges humains paléolithiques de la grotte d’Isturitz (Pyrénées-Atlantiques)

This paper presents new AMS radiocarbon dates from three human bones housed at the Musée des Antiquités Nationales (Saint-Germain-en-Laye) and found during the Saint-Périer excavations in the Isturitz cave. This cave, located in the foothills of the western Pyrenees, is a major site of the Franco-Cantabrian region. It is well-known for having yielded a major Palaeolithic sequence with rich Magdalenian levels indicating long and intense occupation by human groups during the Upper Palaeolithic. The cave is divided into two main chambers : the Isturitz chamber (or Grande Salle) and the Saint-Martin chamber (fig. 1). Research was conducted in Isturitz by E. Passemard between 1912 and 1923, by R and S. de Saint-Périer between 1928 and 1948 (Passemard, 1924 and 1944 ; Saint-Périer, 1930 and 1936 ; Saint-Périer and Saint-Périer, 1952), and by C. Normand and others since 1999. The excavations of E. Passemard and R. and S. de Saint-Périer yielded an important assemblage of human remains from both adult and immature individuals. The cultural attribution of these bones is problematic, especially because of the complexity of the stratigraphy and the ancient date of the excavations (fig. 2) ; although the bones come from different levels of the sequence discovered in the cave, they are usually attributed to the Magdalenian (Gambier, 1990-1991). More than 80% of this assemblage consists of fragmented elements of the skull and mandible ; anthropic modifications indicate a processing of corpses linked to either funerary or ritual, warlike practices (flesh removal, disarticulation, intentional breakage, sometimes shaping and engraving of the bones : Gambier, 1990-1991). While fragmentation limits the interest of these remains as regards the study of skeletal morphology, the anthropic modifications of the bones mean they are of major interest for understanding the mortuary behaviour of Upper Palaeolithic populations. Three samples (fig. 3) were selected among the human remains found in the Grande Salle by R. and S. de Saint-Périer. Two are from layer II (Middle Magdalenian) and one is from layer III (Upper Gravettian). They include : IST II-23-1937, a fragment (5.5 cm × 6.4 cm) of an adult parietal ; IST II-41-1933, a fragment (7.5 cm × 6.5 cm) of an adult frontal ; and IST III-53-1937, a fragment of an adult parietal (6.7 cm × 6.0 cm). These three fragments belong to three different adults. The bones were photographed and analysed prior to sampling. Sampling was done in areas without glue, consolidators, varnish or ink. They were submitted for AMS 14C dating at Groningen (Centre for Isotope Research, Groningen University). The results indicate that the two bones 45328 IST II-23-1937 and 45332 IST III-53-1937 are dated respectively in the range of 18461-17652 and 18043-17540 cal. BP, corresponding to the Middle Magdalenian. The third, 45329 Isturitz II -41-1933, is associated with a range of 16351-15174 cal. BP, contemporary with the Upper Magdalenian. The date obtained on the sample from layer III confirms the hypothesis of contamination of layer III, top of the Gravettian, by layer II, Middle Magdalenian. The assumption of the majority of human remains pertaining to the Middle Magdalenian is therefore admissible. The date obtained for the third sample is problematic because it falls within an interval corresponding to the Upper Magdalenian : it is close to the AMS date obtained on a fragment of antler barbed point (’ harpoon head’) from layer F1 (fig. 4 : 13095 ± 55 BP or 16441-15223 cal. BP ; Szmidt et al., 2009). Like the others, this bone sample had anthropic modifications, and therefore the date could have been expected to integrate the interval corresponding to the Middle Magdalenian. Therefore, either the reliability of that date is uncertain — but no arguments support this hypothesis — or the processing of the corpse and head in the Upper Magdalenian was, if not identical, in any case, at least similar to that attested in the Middle Magdalenian. Isolated human bones with anthropic modifications also exist in the Upper Magdalenian (Gambier, 1996) so this hypothesis cannot be ruled out. However, in the Grande Salle of Isturitz, the transition between Middle and Upper Magdalenian is visible in many categories of archaeological objects and fields of activity (flint and antler equipment, game hunted, ornaments and art : Pétillon, 2004 and 2006 ; Langlais, 2010 ; Laroulandie in Pétillon et al., to be published). These differences argue for major changes in human behaviour at the Middle-Upper Magdalenian transition. If the date on the human bone is reliable, it would mean that mortuary behaviour continued, at least partially, beyond these transformations. Other dates are necessary to further the discussion and the dating programme on human bones should be continued. However, the assumption that the majority of human remains at Isturitz pertain to the Middle Magdalenian is reinforced by these new dates.

Along-strike extrusion at the transition between thin- and thick-skinned domains in the Pyrenean Orogen (northern Spain)

Abstract In the south-verging portion of the western Pyrenean Orogen, a Mesozoic basin and part of the adjacent continental margin were deformed during the Pyrenean collisional stage. The slight obliquity between extensional and compressional trends, and the presence of a Mesozoic Transfer Zone, implied that both extensional domains were exposed along-strike of the belt in the same structural position. These two areas are not only characterized by the widespread reactivation of inherited fault systems but also by different styles of deformation related to the presence or absence of an evaporitic detachment level. To the east, in the Mesozoic basin, a large-displacement south-directed low-dipping thrust detached above Triassic evaporites is present. To the west, in the Mesozoic continental margin, thick-skinned and deeply rooted right-lateral and reverse faults become first-order elements. The presence of a strike-slip component produced the eastwards extrusion of the eastern portion of the Mesozoic continental margin, which imposed an along-strike shortening at the edge of the extruded block. The transitional area from thin- to thick-skinned style of deformation, from a dip-slip to a transpressive framework, and the area accommodating the extrusion are located along a north–south-orientated band representing the southern extension of a Mesozoic Transfer Zone.

Marriage patterns in the Western French Pyrenees during the 1800–1899 period: data from the village of Béost (Ossau Valley, Béarn)

The Western Pyrenees are made up of isolated valleys that were associated until recently with low marriage mobility. We chose to study the Ossau Valley (Bearn, France), which has one of the least mobile populations in this area. Marriage patterns in the village of Beost were analyzed over the 1800-1899 period. Data on 238 marriages obtained from parish, civil and notarial registers were used to assess the following variables: seasonality, endogamy rate, isonymic marriages and the consanguinity coefficient calculated from isonymy and from ecclesiastical dispensations. A clear seasonal marriage pattern emerged, linked to religious and local social parameters. Levels of endogamy were 57.5% in the village and 92.4% in the valley as a whole. The consanguinity coefficients calculated from isonymy (Ft) and ecclesiastical dispensations (α) were 0.0031 and 0.0040 respectively. The negative non-random component of F (Fn) indicated that Beost residents avoided contracting potentially consanguine isonymic marriages. These biodemographic markers were compared to those observed among various other 19th century mountain populations in Western Europe.