Les terrasses fluviatiles quaternaires de la Somme à Abbeville : 150 ans de recherches mêlant géologie et archéologie,de Boucher de Perthes à aujourd’hui

Paleolithic localities associated with fossil fluvial formations of the Somme River at Abbeville have played a significant role in the recognition of human antiquity. From the end of the 18th century, the work carried out in particular by the “Société d’émulation d’Abbeville” led to the emergence of studies in the Somme valley on both Quaternary Geology and Prehistory. It was within this scholarly society that Jacques Boucher de Perthes initiated his research on the famous localities of Menchecourt, Hospital and Moulin Quignon in 1837. These observations were quickly confirmed by geologists such as Albert Gaudry, Charles-Joseph Buteux or Joseph Prestwich. It was the latter who introduced the Abbeville deposits into the United-Kingdom scientist community and his observations were used as early as 1859 by Charles Lyell to demonstrate the antiquity of the archaeological remains collected from these localities. However, the controversy surrounding by the discovery of the human jaw of Moulin Quignon (1863–1864), which undermined the credibility of this locality for a long time, led to the decrease of the archaeological researches in the Somme valley, and in particular in Abbeville, but it then resumed quite quickly. However, if the work carried out by Geoffroy d’Ault du Mesnil from 1875 to 1898 had the merit to reaffirm the archaeological importance of the Abbeville deposits and to reveal the complexity of their Quaternary records, the geographical and stratigraphic imprecision resulting from these rare publications, coupled with the gradual abandonment of the various gravel pits whose exploitation he followed, cast a significant discredit on these discoveries and on the stratigraphical observations he made there. The researches carried out then by Victor Commont at Carpentier Quarry between 1904 and 1918 were characterized by the excellence of the stratigraphic and iconographic data he produced for each of the studied sites. However the absence of archaeological discoveries in the fluvial deposits he studied lead the prehistorians who succeeded him increasingly doubted of the veracity of Ault's observations, despite the efforts made by Abbé Henri Breuil to reconcile these with Commont's observations. Between the two world wars, Breuil and Léon Aufrère resumed the study of the Abbeville deposits then still accessible, tried to ensure their preservation, through the purchase and protection of the Carpentier and Léon quarries, a decisive intervention in the archaeological rehabilitation of these deposits. These works were at the origin of the chronostratigraphic studies carried out on these major localities of the ancient European prehistory until today. Over the past ten years, some of these localities have been studied again, thus largely confirming the observations made by the elders (Boucher de Perthes, d’Ault du Mesnil, Commont) and validating the major place of Abbeville in the understanding of ancient prehistory settlement of northwestern Europe.     

Human Tracks from Quaternary Tufa Deposits,Cuatro Cienegas,Coahuila, Mexico

In 1961, two human footprints were excavated from the Cuatro Cienegas region of Coahuila, Mexico, but for decades were not studied scientifically or deposited in any museum. Consequently, knowledge of the locality where they were found was lost. Once the two tracks were relocated they found their way to the Museo del Desierto, Saltillo (Coahuila) where they were placed on display with a tentative label suggesting an early Holocene age (10,000 B.C.). This inference was based only on the known antiquity of humans in the region determined from previous archaeological work and two dated sediment cores close to the footprint site. It was not until 2006 that the presumed footprint discovery site was rediscovered, revealing more than 20 additional well-preserved prints, in at least four trackways representing several different individuals with foot lengths ranging from about 23–27 cm. The tracks include one well-preserved trackway providing step and stride measurements. A poorly preserved cervid trackway and a possible duck footprint have also been identified. The footprints are preserved in hard tufa. Geochemical evidence suggests the tracks were made during periods of increased aridity.     

Life mode of in situ Conularia in a Middle Devonian epibole

Abstract: Exceptionally abundant specimens of Conularia aff. desiderata Hall occur in multiple marine obrution deposits, in a single sixth‐order parasequence composed of argillaceous and silty very fine sandstone, in the Otsego Member of the Mount Marion Formation (Middle Devonian, Givetian) in eastern New York State, USA. Associated fossils consist mostly of rhynchonelliform brachiopods but also include bivalve molluscs, orthoconic nautiloids, linguliform brachiopods and gastropods. Many of the brachiopods, bivalve molluscs and conulariids have been buried in situ. Conulariids buried in situ are oriented with their aperture facing obliquely upward and with their long axis inclined at up to 87 degree to bedding. Most specimens are solitary, but some occur in V‐like pairs or in radial clusters consisting of three specimens, with the component specimens being about equally long or (less frequently) substantially different in length. The compacted apical end of Conularia buried in situ generally rests upon argillaceous sandstone. With one possible exception, none of the examined specimens terminates in a schott (apical wall), and internal schotts appear to be absent. The apical ends of specimens in V‐like pairs and radial clusters show no direct evidence of interconnection of their periderms. The apical, middle or apertural region of some inclined specimens abuts or is in close lateral proximity to a recumbent conulariid or to one or more spiriferid brachiopods, some of which have been buried in their original life orientation. The azimuthal bearings of Conularia and nautiloid long axes and the directions in which conulariids open are nonrandom, with conulariids being preferentially aligned between 350 and 50 degree and with their apertural end facing north‐east, and nautiloids being preferentially aligned between 30 and 70 degree. Otsego Member Conularia were erect or semi‐erect, epifaunal or partially infaunal animals, the apical end of which rested upon very fine bottom sediment. The origin of V‐like pairs and radial clusters remains enigmatic, but it is probable that production of schotts was not a regular feature of this animal’s life history. Finally, conulariids and associated fauna were occasionally smothered by distal storm deposits, under the influence of relatively weak bottom currents.     

Microbiological Reduction of Sulphates in Salty Environments and Mineralogical Characterization of the Transformation Products

This research was focused on the selection, growth and identification of SRB from soils that were subjected to long-term activity of brine, and an evaluation of mineral phases formed during the biodegradation of organic compounds and sulphate reduction. Isolated communities of anaerobic microorganisms were incubated on Postgate C medium with lactate and/or ethanol as the sole carbon source and were adapted for growth at 4% NaCl. Active reduction of sulphates with simultaneous biodegradation of organic compounds was observed in all cultures. The largest reduction of sulphates was noted in cultures with lactate as the sole carbon source; it reached 1438 mg/L, which corresponds to a 43% reduction of sulphates introduced to the medium. SRB activity in the biodegradation of organic compounds varied between 20 and 80% and depended on the level of salinity of the environment in which the SRB communities were isolated, and on the electron donor applied. The presence of biotransformation products in the post-culture deposits in the form of elemental sulphur reflects the activity of the communities. Additionally, the influence of selected communities on the salinity index was analyzed. Active SRB communities decreased the salinity of the environment by as much as 50%. Sulphate-reducing bacteria are an important group of anaerobic microorganisms, especially considering their participation in such geological processes as mineral precipitation and mineralization of organic matter in extreme environmental conditions, including high salinity.     

Microbial and enzymatic control of pitch in the pulp and paper industry

Pitch control is an important aspect in pulp and paper manufacture, and the first example where microbial biotechnology provided successful solutions in this industrial sector. Triglycerides cause deposits in softwood mechanical pulping, and both microbial and enzymatic products have been commercialized to be applied on wood and pulp, respectively. The former are based on colorless strains of sapstain fungi. The latter are improved lipases, including thermostable variants from directed evolution. These enzymes are among the additives of choice in pulping of high-resin-content softwoods. However, lipases are not useful when pitch originates from other lipids, such as steroids and terpenes, and the sapstain inocula are also only partially effective. In the search for stronger biocatalysts to degrade recalcitrant lipids, the potential of white-rot fungi and their enzymes has been demonstrated. When inocula of these fungi are used, wood treatment must be controlled to avoid cellulose degradation. However, the efficiency and selectivity of the laccase-mediator system permits its integration as an additional bleaching stage. A double benefit can be obtained from these treatments since pitch is controlled at the same time that residual lignin is removed facilitating the implementation of totally chlorine free pulp bleaching.     

Neritic carbonate for six submerged coral reefs from northern Australia: Implications for Holocene global carbon dioxide

Total contribution of six recently discovered submerged coral reefs in northern Australia to Holocene neritic CaCO₃ and CO₂ is assessed to address a gap in global budgets. CaCO₃ production for the reef framework and inter-reefal deposits is 0.26–0.28 Mt. Holocene CO₂ production is 0.14–0.16 Mt. Coral and coralline algae are the dominant sources of Holocene CaCO₃ although foraminifers and molluscs are the dominant constituents of inter-reefal deposits. The total amount of Holocene neritic CaCO₃ produced by the six submerged coral reefs is several orders of magnitude smaller than that calculated using accepted CaCO₃ production values because of very low production, a ‘give-up’ growth history, and presumed significant dissolution and exports. The contribution of submerged coral reefs to global Holocene neritic CaCO₃ is estimated to be 0.26–0.62 Gt, which yields 0.15–0.37 Gt of CO₂. This amount of CO₂ is 0.02–0.05% of the 780 Gt added to the atmosphere since 18 kyr BP. Contributions from Australian submerged coral reefs are estimated to be 0.05 Gt CaCO₃ and 0.03 Gt CO₂ for an emergent reef area of 47.9 × 10³ km². Based on the growth history of the submerged coral reefs in the Gulf of Carpentaria, maximum global Holocene CaCO₃ fluxes could have attained 0.3 Gt yr^− 1 between 11 and 7 ka BP. This additional CaCO₃ would have culminated in a maximum CaCO₃ production from all (emergent and submerged) coral reefs of 1.2 Gt yr^− 1 and neritic CaCO₃ production of 2.75 Gt yr^− 1. The dilemma remains that the global area and CaCO₃ mass of submerged coral reefs are currently unknown. It is inevitable that many more submerged coral reefs will be found. Our findings imply that submerged coral reefs are a small but fundamental source of Holocene neritic CaCO₃ and CO₂.     

Cretaceous and Cenozoic non-marine deposits of the Northern South Yellow Sea Basin, offshore western Korea: palynostratigraphy and palaeoenvironments

Palynological analyses of two wells (Haema-1 and Kachi-1) located in two sub-basins of the Northern South Yellow Sea Basin have been carried out in order to establish a palynostratigraphic breakdown of the sedimentary succession and to determine environments of deposition. Seven assemblage zones and two assemblage subzones have been erected on the basis of frequency variations in, and occurrences of, biostratigraphically significant palynomorphs as follows: Classopollis-Ephedripites Assemblage Zone (AZ): Barremian-Albian; Alisporites-Aquilapollenites-Penetetrapites AZ, which is subdivided into an Alisporites-Rugubivesiculites Assemblage Subzone: Cenomanian-Lower Maastrichtian, and an Aquilapollenites-Penetetrapites Assemblage Subzone: Upper Maastrichtian; Momipites-Coryluspollenites AZ: Paleocene; Caryapollenites-Inaperturopollenites AZ: Lower-Middle Eocene; Quercoidites-Pinuspollenites AZ: Upper Eocene; Liquidambarpollenites-Fupingopollenites-Magnastriatites AZ: Lower-Middle Miocene; Graminidites-Persicarioipollis AZ: Pliocene. The depositional environments represented by the well sections are considered to have been generally fluvio-lacustrine, and the climate to have varied between semi-arid and wet, and subtropical and warm temperate, except during the Late Eocene and Pliocene when a cool-temperate climate prevailed. Six stages in the development of the sub-basins are recognised. These are: (1) initial stage of rift or pull-apart basin-formation during the Late Jurassic?-Cretaceous; (2) subsidence from the Paleocene to Middle Eocene; (3) alternation of uplift and subsidence in the Late Eocene; (4) synrift inversion and erosion through the Oligocene; (5) uplift during the Early Miocene; and (6) widespread subsidence from the Middle Miocene onwards apart from during the Early Pliocene when the region was subjected to uplift once more.     

Bivalves from Carboniferous glacial deposits of western Argentina

Late Palaeozoic glaciation of Gondwana affected ecosystems and caused provincialism in the earth’s biota. Periglacial seas favored the origin of endemic genera and species, and remarkable differences exist with faunas of the Palaeoequatorial realm. Carboniferous glacimarine deposits are almost everywhere associated with theLevipustula levis “cold” fauna. These bio- and lithofacies are ubiquitous along the peri-Gondwana belt that stretches from western Argentina to eastern Australia, including central Patagonia and Antarctica. Both glacial sediments and theLevipustula levis Zone are assumed to date from the beginning of the Namurian to an indeterminated part of the early Westphalian. The bivalve fauna associated with the Carboniferous glacial deposits of western Argentina is described, including four new species:Promytilus grandis n. sp.,Leptodesma (Leiopteria) aredesi n. sp.,Oriocrassatella andina n. sp., andMyofossa calingastensis n. sp. Six insufficiently preserved species are left in open nomenclature:Leptodesma (Leiopteria) n. sp.,Euchondria n. sp.,Schizodus n. sp.,Promytilus sp.,Cypricardinia? sp., andStreblopteria? sp.; it proved even impossible to decide whether a badly damaged incomplete specimen belongs toMyonia orVacunella. Five other species, which are known from single specimens, are assigned tentatively to the generaPhestia, Atomodesma, Pyramus, Vacunella, andPleurophorella.