Alpes De Haute Provence Research Articles

The Geotouristic Project “the Geological Adventure” to the Rescue of an Iconic World Heritage Geosite, the Ammonites Slab of Digne-les-Bains (National Geological Nature Reserve of Haute-Provence and Unesco Global Geopark, France)

Protected under National Nature Reserve, managed by the Departmental Council of the Alpes de Haute-Provence, and labeled UNESCO Geopark, the Ammonites Slab of Digne-les-Bains (SE France) exhibits 1,550 ammonites over a large open-air surface. Despite the virtual absence of special enhancement for the visitors, this spectacular geosite of high scientific and heritage value has played an important role in the years 1990–2000 in the emergence of notions of geological heritage, geological nature reserve, geotourism, and Geopark. Due to its exposure to mountain weather conditions, the Slab suffers from significant conservation issues. Several studies have shown that its condition was much worse than expected. Without major restoration work, the Slab was in danger of collapse in the short term. Given the high cost of the needed rescue work, the geotourism project “The Geological Adventure” was developed under European Interreg ALCOTRA funding. More broadly, this project aims to develop a sustainable experiential geotourism around the geoheritage of the Southwestern Alps cross-border (France–Italy), partly in situ and thanks to digital tools (22 geosites concerned). An important place is given to scientific pedagogy. Concerning the Ammonites Slab, the project consisted of (1) stabilizing and ensuring the sustainability of the fossiliferous layer; (2) planning and developing the overall geosite (parking area, reception area, observation platform); (3) allowing accessibility for people with disabilities; and (4) offering progressive and immersive educational mediation to make scientific culture accessible to as many people as possible.

A new fossil from the early Oligocene of Provence (France) increases the diversity of early Gruoidea and adds constraint on the origin of cranes (Gruidae) and limpkin (Aramidae)

Cranes (Gruidae) have a poor early fossil record, and the oldest ascertained fossils hitherto referred to the family (either as crown or stem-representatives) date back to the early or middle Miocene. Other Gruoidea have an even scarcer fossil record. Psophiidae and Aramidae are virtually unknown as fossils, and other fossil representatives of the Gruoidea are difficult to place. Here, we describe a new fossil that sheds new light on the early history of stem Gruidae, a right coracoid in dorsal view preserved on slab in limestone laminites of the early Oligocene « Calcaires de Campagne-Calavon» (Alpes de Haute Provence, France). It is compared with extant and fossil morphologically related taxa, and appears to differ from all extant and fossil relatives in the Gruoidea. The new fossil represents, among the Gruoidea, a new genus and species, Palaeogeranos tourmenti, placed within the clade (Aramidae + Gruidae) that is referred to as epifamily Gruoidae. Within Gruoidae, placement is tentative and we give arguments leading to propose a possible position as a stem Gruidae, a hypothesis to be tested with further discoveries. In this hypothesis, aged around 30 million years, the new fossil suggests that the stem of the Gruidae would date back to at least the earliest Oligocene, which is still compatible with current molecular phylogenetic divergence dates estimations, given the confidence intervals. Palaeogeranos will potentially help refining future calibrations for molecular phylogenetic studies, at least concerning the earliest Gruoidae (Aramidae + Gruidae).

Improved Crop Classification with Rotation Knowledge using Sentinel-1 and -2 Time Series

Leveraging the recent availability of accurate, frequent, and multimodal (radar and optical) Sentinel-1 and -2 acquisitions, this paper investigates the automation of land parcel identi- fication system (LPIS ) crop type classification. Our approach allows for the automatic integration of temporal knowledge, i.e., crop rotations using existing parcel-based land cover databases and multi-modal Sentinel-1 and -2 time series. The temporal evolution of crop types was modeled with a linear- chain conditional random field, trained with time series of multi-modal (radar and optical) satellite acquisitions and associated LPIS. Our model was tested on two study areas in France (≥ 1250 km2) which show different crop types, various parcel sizes, and agricultural practices: . the Seine et Marne and the Alpes de Haute-Provence classified accordingly to a fine national 25-class nomenclature. We first trained a Random Forest classifier without temporal structure to achieve 89.0% overall accuracy in Seine et Marne (10 classes) and 73% in Alpes de Haute-Provence (14 classes). We then demonstrated experimentally that taking into account the temporal structure of crop rotation with our model resulted in an increase of 3% to +5% in accuracy. This increase was especially important (+12%) for classes which were poorly classified without using the temporal structure. A stark posi- tive impact was also demonstrated on permanent crops, while it was fairly limited or even detrimental for annual crops.

Paleoenvironmental context and significance of a partial elasmosaurid skeleton from the Albian of Haute-Provence, France

The Early–Late Cretaceous transition (late Albian–early Cenomanian; ~100 Ma) witnessed marked environmental changes and a deep reorganization of the marine fauna. The impact of these environmental and biotic changes on Tethyan marine vertebrates is poorly understood, due to a fragmentary fossil record. Here we report upper Albian marine vertebrate remains, including a partially articulated plesiosaurian skeleton, from a fossiliferous glauconite-rich bed in the Alpes de Haute-Provence, France. The fossiliferous horizon produced a diversified invertebrate fauna including ammonoids and belemnoids. The ammonite fauna is abundant and diversified, indicating the Mortoniceras fallax ammonite Zone. The calcareous nannofossil biomarkers date the bed to the NC10a Zone. The fossiliferous bed consists of glauconitic marls enriched in planktic foraminifera and occurs amongst a monotonous succession of alternating marlstones and limestone beds. The vertebrate fauna consists of chondrichthyans and marine reptiles. Chondrichthyans are represented by five Lamniformes species (dominated by Sphenodus) and comprise predator taxa probably living in open marine temperate waters. The site yielded a large, partial post-cranial plesiosaurian skeleton with articulated elements, belonging to an elasmosaurid and representing one of the most complete Albian plesiosaurian specimens known from Europe. The abundance and preservation of the collected fossil remains are best explained by their concentration during a basin-scale episode of very low sedimentation corresponding to a major episode of marine transgression, associated with a lower oxygenation of bottom waters. These findings indicate that the newly discovered fossiliferous bed holds promising clues about the evolutionary history of major groups of marine vertebrates and ammonites near the Early–Late Cretaceous transition.

A revision of the genus Conocrinus d'Orbigny, 1850 (Echinodermata, Crinoidea, Rhizocrinidae) and its place among extant and fossil crinoids with a xenomorphic stalk.

The genus Conocrinus d'Orbigny, 1850 (Crinoidea, Bourgueticrinina) was established on the basis of two aboral cups that had previously been described as Bourgueticrinus thorenti d'Archiac, 1846. One of these (now considered lost) came from the "Rocher du Goulet" at the base of the Biarritz section (Bartonian, Côte des Basques, southwest France). D'Archiac figured only the second cup; this belongs to the d'Orbigny Collection and is still housed in the palaeontological collection of the Muséum national d'Histoire naturelle (Paris) as the lectotype of the species, C. thorenti. It appears that it was collected from Priabonian levels exposed near Castellane (Alpes de Haute Provence, southeast France). New observations on this cup, as well as a detailed study of the characters of aboral cups, columnals and proximal brachials in a few extant and fossil species classically attributed to Conocrinus or to closely related genera such as Democrinus, Rhizocrinus and Tormocrinus, have yielded arguments for a revision of the taxonomy and interrelationships of extant and fossil taxa in the family Bourgueticrinidae. Conocrinus(= Tormocrinus), as here interpreted, includes six Eocene species: C. thorenti, C. archiaci, C. cahuzaci n. sp., C. duperrieri, C. cf. suessi and C. veronensis. Numerous extinct species previously attributed to Conocrinus or Democrinus are here transferred to two new genera which first occur in the lower Paleocene: Paraconocrinus n. gen. (type species: P. pyriformis) and Pseudoconocrinus n. gen. (type species: P. doncieuxi). Aboral cups from the "Rocher du Goulet" (Biarritz) are here assigned to Paraconocrinus pellati n. gen., n. sp., while the Danian species Democrinus maximus is transferred to Pseudoconocrinus n. gen. A new genus, Cherbonniericrinus, is created to accommodate a single extant species, Ch. cherbonnieri, previously attributed to Conocrinus, while the extant genus Rhizocrinus, closely related to Democrinus, is resurrected. Conocrinus and closely related genera are derived from a bourgueticrinine lineage the first record of which is from the lower Campanian, with the new genus Carstenicrinus. These are all attributed to the family Rhizocrinidae which is here considered distinct from the family Bourgueticrinidae. Rhizocrinids rapidly diversified immediately after the Cretaceous-Paleogene (K/Pg) event. Cretaceous taxa previously placed within the family Bourgueticrinidae now appear to be polyphyletic. Some of them do not belong to Bourgueticrinina, such as those of the Dunnicrinus lineage. Interrelationships of Rhizocrinidae and other post-Palaeozoic families having a xenomorphic stalk are discussed.

Heteroceras gracile sp. nov., a new species of Heteroceras Orbigny, 1849, from the upper Barremian of Morteiron (Alpes de Haute-Provence, France)

The species Heteroceras gracile sp. nov. is described; it is a small and slender species, with a small helix and hamuliniform morphology, previously considered as an atypical variant of Heteroceras baylei (Reynes, 1876). In southeast France, it is mainly known in the Morteiron section (Alpes de Haute-Provence, France), but the species is also present in Bulgaria and possibly in Japan.

Memorias intimas y espacio social: el pueblo de Peyruis (Francia) a mediados del siglo XX

The memorable places (landmarks) have a fundamental place in the symbolic marking of territory and in its connexion with official history. They express a collective identity which is shown at different political and sociological levels, from the nation down to the family- a scale of analysis hitherto neglected. To see how individuals' space-time mesh with that of society, I began to research my own family and its birthplace - Peyruis, Alpes de Haute-Provence in France. By reconstructing the private geography of three sisters and a brother in this small, 1940's Provenzal town, we move from institutional memorials to commonplace ones : everyday places more linked to daily activities than regular acts of remembrance. These small significant sites are found in a social space. They embody virtual and limited in time appropriation of a public territory by a private memory.

Probable aestivation burrows from the Eocene/Oligocene transition in south-eastern France and their palaeoenvironmental implications

Enigmatic biogenic structures are reported from the Palaeogene of south-eastern France in the Castellane-Blieux area (Alpes de Haute-Provence French Department). They occur at the Eocene/Oligocene transition at the top of the Marnes Bleues Formation, which corresponds to a clearly defined regressive sequence, where thick marls are overlain by lacustrine limestones or sandstones. The marls have abundant shallow marine fauna and the upper part of the Formation corresponds to a rapid transition to non-marine deposits. The studied structures exhibit three main morphologies: vertical shafts, furrows, and tunnels. They can also form dense clusters and cross-cut marginal marine crustacean burrows such as Psilonichnus. By comparison with modern and fossil examples, these trace fossils are interpreted as probably aestivation burrows. The possible trace-makers could be lungfish (in particular for the common vertical burrows) or amphibians (for the furrows and tunnels). The occurrence of these different aestivation burrows defines the border of a basin and probably indicates increasing droughts on the coastal plain. This could reflect the well-known development of arid conditions in south-eastern France at the beginning of the Oligocene.

Annual fossil organic carbon delivery due to mechanical and chemical weathering of marly badlands areas

ABSTRACTA key issue in the study of the carbon cycle is constraining the stocks and fluxes in and between C‐reservoirs. Among these, the role and importance of fossil organic carbon (FOC) release by weathering of outcropping sedimentary rocks on continental surfaces is still debated and remains poorly constrained. Our work focuses on FOC fluxes due to chemical and mechanical weathering of marls in two experimental watersheds with typical badlands geomorphology (Draix watersheds, Laval and Moulin, Alpes de Haute Provence, France). Organic matter from bedrock, soil litter and riverine particles are characterized by Rock‐Eval 6 pyrolysis. FOC fluxes due to mechanical weathering are then estimated by monitoring the annual particulate solid exports at the outlets of the watersheds (1985–2005 period). FOC fluxes from chemical weathering were calculated using Ca2+ concentrations in dissolved loads (year 2002) to assess the amount of FOC released by the dissolution of the carbonate matrix. Results show that FOC delivery is mainly driven by mechanical weathering, with a yield ranging from 30 to 59 t km‐2 yr‐1 in the Moulin (0.08 km2) and Laval (0.86 km2) catchments, respectively, (1985–2005 average). The release of FOC attributed to chemical weathering was 2.2 to 4.2 t km‐2 for the year 2002. These high FOC fluxes from badlands are similar to those observed in tectonically active mountain catchments. At a regional scale, badland outcropping within the Durance watershed does not exceed 0.25% in area of the Rhône catchment, but could annually deliver 12 000 t yr‐1 of FOC. This flux could correspond to 27% of the total particulate organic carbon (POC) load exported by the Rhône River to the Mediterranean Sea. At a global scale, our findings suggest that erosion of badlands may contribute significantly to the transfer of FOC from continental surfaces to depositional environments. Copyright © 2012 John Wiley & Sons, Ltd.

Farmers adoption of integrated crop protection and organic farming: Do moral and social concerns matter?

We investigate empirically the role of moral and social concerns in farmers' decision to adopt integrated crop protection (IP) and organic farming (OF). A survey questionnaire has been sent to 1286 fruit-growers and vegetable producers located in the French areas of Alpes de Haute Provence, Hautes-Alpes and Vaucluse. Analysis of individual responses ( N = 243) shows that, although economic concerns play a strong role, a significant number of respondents give high importance to moral and social ones. We also examine how these considerations matter according to different crop protection strategies, that is, conventional farming, IP and OF. Using a multinomial logistic regression, we find that (1) social concerns ( e.g., showing to others one's environmental commitment) drive both IP and OF adoption, (2) moral concerns ( e.g., do not feel guilty about one's choices) increase the probability of organic farming adoption only, and (3) farmers who give high importance to economic concerns ( e.g., cutting production costs) are less likely to adopt OF.

High resolution, quantitative reconstruction of erosion rates based on anatomical changes in exposed roots at Draix, Alpes de Haute-Provence — critical review of existing approaches and independent quality control of results

Extensive areas of the French Alps are underlain by Jurassic black marls. Wherever these “terres noires” crop out they become subject to intense erosion, causing major sedimentation in regional reservoirs and river systems. In the badlands near Draix (Alpes de Haute-Provence, France), measured sediment rates were obtained at the plot scale by surface elevation change-based methods and at the catchment scale by monitoring sedimentation in dams. In this study, we use a dendrogeomorphic approach based on anatomical changes in exposed roots of Pinus sylvestris L. to accurately quantify continuous denudation rates. A total of 123 cross sections (75 from buried and 48 from exposed roots of 23 trees) were sampled in the Moulin basin. The size and position of roots at the time of exposure was determined via anatomical variations in the annual growth rings of roots. In cross sections of buried roots, a sharp reduction of earlywood tracheid lumen area — a growth signature which has traditionally been used to determine the moment of root denudation — was observed as soon as erosion reduced soil cover to ≤ 3 cm. As a consequence, estimates of eroded soil thickness had to be adjusted to take account of this bias. Bias-adjusted, averaged, medium-term erosion rates derived from exposed roots vary between 6 and 7 mm y –1 at Moulin basin depending on the importance accorded to the uplift of roots after exposure. Values are significantly correlated to slope angle and match with erosion rates derived from monitored iron stakes (5.7 mm y –1) or measurements of sediment yield in retention dams (4.7 mm y –1) at the outlet of the Moulin basin. Besides demonstrating that the interpretation of anatomical signatures in tree roots to erosion have to be revised, this paper also shows that dendrogeomorphic analyses of roots are indeed a powerful tool for the quantification of minimal rates of soil erosion in environments where measurements of past activity are not available.

Formal proposal for the Bathonian GSSP (Middle Jurassic) in the Ravin du Bès Section (Bas-Auran, SE France)

The Bathonian Global Stratotype Section and Point (GSSP) is proposed at the base of limestone bed RB071 (bed 23 in Sturani 1967) in the Ravin du Bès Section (43° 57′ 38′′ N, 6° 18′ 55′′ E), Bas-Auran area, “Alpes de Haute Provence” French department. The Ravin du Bès Section, as formal candidate GSSP for the base of the Bathonian Stage, satisfies most of the requirements recommended by the International Commission on Stratigraphy: 1) The exposure extends over 13 m in thickness. At the Bajocian-Bathonian transition, no vertical (bio-, ichno- or tapho-) facies changes, condensation, stratigraphic gaps or hiatuses have been recorded. Structural complexity, synsedimentary and tectonic disturbances, or important alterations by metamorphism are not relevant constraints. 2) There is a well-preserved, abundant and diverse fossil record across the boundary interval, with key markers (ammonites and nannofossils) for worldwide correlation. The base of the Bathonian Stage and Zigzag Zone in Bas-Auran corresponds to the first occurrence level of Gonolkites convergens Buckman, which coincides with the first occurrence of Morphoceras parvum Wetzel. Calcareous nannofossils, as secondary global marker, are present in all beds and allow characterizing the Bajocian-Bathonian transition. 3) Regional analyses of sequence stratigraphy and manganese chemostratigraphy are available. Spectral gamma-ray data corroborate an Early Bathonian deepening half-cycle of second order. 4) The criteria of accessibility, conservation and protection are assured by the “Réserve Naturelle Géologique de Haute Provence”. The Cabo Mondego Section (Portugal) is suggested as the Bathonian auxiliary section and point (ASSP) within this GSSP proposal.

Mediterranean Neocomian belemnites, part 3: Valanginian-Hauterivian belemnites

The classical papers of Raspail (1829, 1830) and Duval-Jouve (1841) described a wide range of belemnite species, mainly from the Lower Cretaceous of the Castellane-Peyroules area (Alpes de Haute-Provence, France). The present work focuses mainly on the biostratigraphy of these previously described belemnite taxa for their stratigraphic relationships had not been determined precisely. Here, biostratigraphy is related to the lithologic successions and faunal associations (ammonites) of various outcrops in the area studied. Complementary data were obtained from the La Lagne, Les Allaves and Pas d'Escale sections (Alpes de Haute-Provence, France). And, in order to attain a better understanding of the stratigraphic distribution of Late Valanginian belemnites in condensed glauconitic deposits, these assemblages are compared with belemnites from deeper water successions in the Angles, Source de l'Asse de Moriez, Cheiron areas and those in the vicinity of La Charce and Vergol that are even deeper.

Ammonites from the latest Aalenian–earliest Bathonian of La Baume (Castellane area, SE France): palaeontology and biostratigraphy

Middle Jurassic strata are naturally exposed around the village called La Baume, near Castellane (Alpes de Haute Provence, SE France). We have realized both a detailed log and a bed-by-bed sampling for ammonite biostratigraphy in a 68 metres thick succession of subpelagic marls and limestones (“Calcaires à Zoophycos”) that spans the Middle Jurassic from uppermost Aalenian to lowermost Bathonian. The subpelagic succession can be roughly subdivided into three members. Ammonites from the Upper Aalenian Concavum Zone, all Lower Bajocian Zones (Discites Zone, Laeviuscula Zone including Ovale Subzone, Humpriesianum Zone), one Upper Bajocian Zone (Parkinsoni Zone) and probably one lower Bathonian Zone (Zigzag Zone) were found. A major gap of both the Niortense Zone and the Garantiana Zone, which was not previously described, was detected at the boundary between members 2 and 3. The main palaeontological interest of the ammonite fauna from La Baume is the richness and diversity of the family Sonniniidae, which is the subject of a systematic study and figurated along with some biostratigraphically significant forms. Biostratigraphical results and open problems are discussed.

Using Rock‐Eval 6 pyrolysis for tracking fossil organic carbon in modern environments: implications for the roles of erosion and weathering

AbstractThis work relates to the debate on the fossil organic carbon (FOC) input in modern environments and its possible implication for the carbon cycle, and suggests the use of Rock‐Eval 6 pyrolysis as a relevant tool for tracking FOC in such environments. Considering that such a delivery is mainly due to supergene processes affecting the continental surface, we studied organic matter in different reservoirs such as bedrocks, alterites, soils and rivers in two experimental catchments at Draix (Alpes de Haute Provence, France). Samples were subjected to geochemical (Rock‐Eval 6 pyrolysis) investigations and artificial bacterial degradations. After comparing the geochemical fingerprint of samples, geochemical markers of FOC were defined and tracked in the different reservoirs. Our results confirm the contribution of FOC in modern soils and rivers and display the various influences of weathering and erosional processes on the fate of FOC during its exchange between these pools. In addition, the contrasting behaviour of these markers upon the supergene processes has also highlighted the refractory or labile characters of the fossil organic matter (FOM). Bedrock to river fluxes, controlled by gully erosion, are characterized by a qualitative and quantitative preservation of FOM. Bedrock to alterite fluxes, governed by chemical weathering, are characterized by FOC mineralization without qualitative changes in deeper alterites. Alterite to soils fluxes, controlled by (bio)chemical weathering, are characterized by strong FOC mineralization and qualitative changes of FOM. Thus weathering and erosional processes induce different FOM evolution and affect the fate of FOC towards the global carbon cycle. In this study, gully erosion would involve maintenance of an ancient sink for the global carbon cycle, while (bio)chemical processes provide a source of CO2. Finally, this study suggests that Rock‐Eval 6 pyrolysis can be considered as a relevant tool for tracking FOC in modern environments. Copyright © 2006 John Wiley & Sons, Ltd.

Onlap stratal architectures in the Grès d’Annot: geometric models and controlling factors

Abstract Onlap terminations of deep-marine sandstones in the Grès d’Annot, SE France, exhibit a range of styles, from abrupt onlap to feathering ‘aggradational onlap’ geometries. These are well exhibited in the large exposure of southward onlap terminations at Montagne de Chalufy, on the southern end of the Trois Evêchés Massif (Alpes de Haute Provence). These stratal architectures are here simulated by geometrical models that are governed simply by bounding slope gradients and the ratio of coeval slope to basinal aggradation rates. In cases of no coeval deposition on bounding slopes, pure onlap results. In cases of high slope aggradation rates relative to basinal aggradation rates, a feathered geometry results with successive sandstone beds onlapping against successively younger slope drapes. The cyclicity of alternating sand-rich and sand-poor packets seen at Chalufy results in a stepped climbing trajectory of successive slope base positions, with climb angle equal to bounding slope angle when mud-poor sandy flows deposited sandstone bodies with abrupt onlap, and climbing more steeply when slope drapes are deposited. An implication of this result is that any zones of facies change and palaeocurrent swing that are related to distance from bounding slope will exhibit a comparable vertical trajectory through time. The two end member termination types can be compared with the convergent-baselapping and convergent-thinning seismic facies used in the Gulf of Mexico subsurface and elsewhere. The convergent-baselapping seismic facies may include both abrupt onlap and intervals of feathering aggradational onlap if the presence of slope drapes is not resolvable by the frequency content of the available seismic data.

Post‐mortem ablation of the heart: a medieval funerary practice. A case observed at the cemetery of Ganagobie Priory in the French Department of Alpes de Haute Provence

AbstractThe skeletal remains of a medieval warrior were found in an 11th century tomb in the church of Ganagobie Priory in the French Department of Alpes de Haute Provence. Examination revealed evidence of multiple injuries including an arrow in the thorax, several sword blows, and a fractured sternum. The chest had been opened probably to allow removal of the heart after the last fatal blow to the skull. Post‐mortem ablation of the heart was a widespread medieval funerary practice among elite classes in northern Europe. Numerous cases have been described involving British and French royalty. The practice was based on a mystical Middle Age belief that the heart was the spiritual and moral centre. After ablation, the heart was buried separately in a high place of holy worship where the living could pray for the salvation of deceased's soul. The rest of the body was sometimes dismembered and boiled to keep only the skeleton. Pope Boniface VIII forbade body boiling in 1299. In France the practice of removing and burying the heart in a sacred worship place continued among royalty, noblemen, and ecclesiastics until the Revolution of 1789. A few cases were reported into the 19th century. Copyright © 2004 John Wiley & Sons, Ltd.

Stratigraphie, paléoécologie et foraminifères du paléogène des Alpes Maritimes et des Alpes de Haute-Provence (Sud-Est de la France)

Paleogene sedimentation in the Alpes Maritimes and Alpes de Haute Provence regions is composed of one complete sedimentary sequence. This sequence begins with the continental Formation from Microcodium and continues with the Cerithium layers, the Calcaires Nummulitiques and the Marnes Bleues, which are overlaid by the turbidites of the Gres d’Annot Formation. Sedimentation starts in the Nummulites perforatus zone close to the base of ‘the Truncorotaloides rohri zone (P 14) and ends in the Cassigerinella chipolensis–Pseudohastigerina micra zone (P 18) and the NP21 zone in the upper part of the Gres d’Annot. More biomarkers were used in order to define a more detailed local biozonation (biozones AMP 1 to AMP 7). Four local zones were also defined by the last occurrence of Nummulites millecaput and N. perforatus–N. ptukhiani and then by the first appearance of N. retiatus (AMGF 1–4). The evolution of benthic foraminiferal assemblages shows an increase in bathymetry from the internal platform in the Cerithium layers to the calcareous platform with large foraminifers, then to the external platform and the deep offshore environment of the Marnes Bleues and Gres d’Annot. Low faunal diversity in the Gres d’Annot together with the predominance of agglutinated species indicates a poorly oxygenated, organic rich and turbidite environment. Seven steps (SD 1 to SD 7) in the Eocene marine transgression are shown from East to West by detailed local biozonation and sequence analysis. Gres d’Annot sedimentation is also diachronous, beginning within the Truncorotaloides rohri zone (P 14, AMP 1) in the East and ending within the Pararotalia opima opima zone (P 20, middle Rupelian) in the West (Barreme). Small foraminifer Paleogene fauna from the Alpes Maritimes and Alpes de Haute Provence was studied from 400 samples. It is composed of 378 species. Two new taxa are proposed: Fissurina niceana n. sp. and Globocassidulina alpina n. sp. The species from the Escarene and Gorbio neighborhood described by M. von Hantken (1884) were re-examined.

Erosion quantification in the small marly experimental catchments of Draix (Alpes de Haute Provence, France). Calibration of the ETC rainfall–runoff–erosion model

Erosion rates measured for 15 years in the small (ranging from 0.13 ha to nearly 1 km 2) and steep (30–75%) mountainous marly basins of Draix (South Alps, France) are over 100 tons/ha/year in a badland area devoid of vegetation. In a similar basin, reforested at the end of the 19th century, the sediment yield is considerably reduced (less than 3 tons/ha/year). The analysis of the sediment yield of these torrents reveals the importance of the erosion processes on slopes at the scale of the elementary gully, and the influence of deposition, transport and scouring processes as soon as the channel network of the basin is developed. These processes were modelled by a hydrosedimentologic model developed by Cemagref for flood torrent erosion and called ETC. ETC is an integrated, spatialized and global model, working at the event scale. The rainfall–runoff component and the solid transport component, which involves scouring, deposition and armouring, are well developed. On the other hand, the erosion component is not yet a physically based model as the knowledge on the elementary processes is not enough quantitative. The ETC model was used on a badland basin of 86 ha in area, the Laval, and has shown its ability to simulate both water and sediment flows in mountainous and steep basins. The erosion modelling highlighted the need for a better representation of the slope processes and for more information on the storing of sediments in the channel network. Observations carried out on the influence of the vegetation cover patterns and the links between slopes and channels should be taken into account to improve the model.

Étude par absorptiométrie de la densité minérale osseuse dans une population médiévale (nécropole de Notre Dame du Bourg, Digne, Alpes de Haute-Provence France, XIe-XIIIe et XVIe-XVIIIe s.)

Les auteurs ont etudie dans une population medievale semi-rurale (necropole de Digne, Alpes de Haute-Provence, France) les densites minerales osseuses au col femoral et au triangle de Ward par absorptiometrie biphotonique a rayons X. Apres verification de l’absence de pathologie radiologiquement visible et verification de l’absence de variation inter-mensurations et droite-gauche, les femurs de 18 femmes d’âge au deces de moins de 30 ans et de 40 femmes de plus de 60 ans, reparties en deux periodes archeologiques, Xie-XIIIe et XVIe-XVIIe s. ont ete mesures. La comparaison des densites osseuses, independamment de la periode archeologique, met en evidence une deperdition osseuse post-menopausique dans la population medievale et pre-moderne de la necropole de Digne en Provence, entre le 11e et le 17e s., comparable a celle observee dans les populations industrialisees occidentales actuelles. Elle presente un caractere majeur chez certaines de ces femmes, evocateur d’une osteoporose.