Diet breadth and mortality patterns from Laoya Cave: A primary profile of MIS 3/2 hunting strategies in the Yunnan-Guizhou Plateau,southwest China

Laoya Cave is a long-term occupation site of Late Paleolithic humans in the Yunnan-Guizhou Plateau, southwest China, where abundant lithic, bone materials were recovered. Dating by the AMS technique showed a significant depositional process during marine isotope stage (MIS) 3/2. In this study, the species spectrum was presented from the perspective of zooarchaeology and the mortality profile of large Cervidae was examined to help increase our understanding of the subsistence strategy of local people dealing with climate and environmental changes. The main part of the diet was focused on large Cervidae, and the dominance of Ungulates indicates effective management of the cave and local fauna. On the other hand, the mortality profiles of large Cervidae varied correspondingly with climate change. The evidence indicates a specialized hunting strategy that was also flexible, depending on the prevailing climate and environment.     

A simple model accounting for the uptake,transport, and deposition of wind‐eroded mineral particles in the hyperarid coastal Atacama Desert of northern Chile

As previously observed in marine sediments collected downwind of African or South American continental sources, recent studies of sediment cores collected at the bottom of Mejillones Bay in north Chile (23°S) show a laminated structure in which the amount of particles of aeolian origin and their size create significant differences between the layers. This suggests inter‐annual to inter‐decadal variations in the strength of the local southerly winds responsible for (1) the erosion of the adjacent hyperarid surface of the Mejillones Pampa, and (2) the subsequent transport of the eroded particles towards the bay. A simple model accounting for the vertical uptake, transport, and deposition of the particles initially set into motion by wind at the surface of the pampa is proposed. This model, which could be adapted to other locations, assumes that the initial rate of (vertical) uptake is proportional to the (horizontal) saltation flux quantified by means of White's equation, that particles are lifted to a height (H), increasing with the magnitude of turbulence, and that sedimentation progressively removes the coarsest particles from the air column as it moves towards the bay. In this model, the proportionality constant (A) linking the vertical flux of particles with the horizontal flux, and the injection height (H) control the magnitude and size distribution of the deposition flux in the bay. Their values are determined using the wind speed measured over the pampa and the size distribution of particles collected in sediment traps deployed in the bay as constraints. After calibration, the model is used to assess the sensitivity of the deposition flux to the wind intensity variations. The possibility of performing such quantitative studies is necessary for interpreting precisely the variability of the aeolian material in the sediment cores collected at the bottom of Mejillones Bay. Copyright © 2010 John Wiley & Sons, Ltd.     

A brief history of the solar oblateness. A review

We hereby present a review on solar oblateness measurements. By emphasizing historical data, we illustrate how the discordance between experimental results can lead to substantial improvements in the building of new technical apparatus as well as to the emergence of new ideas to develop new theories. We stress out the need to get accurate data from space to enhance our knowledge of the solar core in order to develop more precise ephemerids and ultimately build possible new gravitational theories.     

Influence of compound bedforms on hydraulic roughness in a tidal environment

The effect exerted by the seabed morphology on the flow is commonly expressed by the hydraulic roughness, a fundamental parameter in the understanding and simulation of hydro- and sediment dynamics in coastal areas. This study quantifies the hydraulic roughness of large compound bedforms throughout a tidal cycle and investigates its relationship to averaged bedform dimensions. Consecutive measurements with an acoustic Doppler current profiler and a multibeam echosounder were carried out in the Jade tidal channel (North Sea, Germany) along large compound bedforms comprising ebb-oriented primary bedforms with superimposed smaller secondary bedforms. Spatially averaged velocity profiles produced log-linear relationships which were used to calculate roughness lengths. During the flood phase, the velocity profiles were best described by a single log-linear fit related to the roughness created by the secondary bedforms. During the ebb phase, the velocity profiles were segmented, showing the existence of at least two boundary layers: a lower one scaling with the superimposed secondary bedforms and an upper one scaling with the ebb-oriented primary bedforms. The drag induced by the primary bedform during the ebb phase is suggested to be related to flow expansion, separation, and recirculation on the downstream side of the bedform. Three existing formulas were tested to predict roughness lengths from the local bedform dimensions. All three predicted the right order of magnitude for the average roughness length but failed to predict its variation over the tidal cycle.     

Permeability profiles in granular aquifers using flowmeters in direct-push wells

Numerical hydrogeological models should ideally be based on the spatial distribution of hydraulic conductivity (K), a property rarely defined on the basis of sufficient data due to the lack of efficient characterization methods. Electromagnetic borehole flowmeter measurements during pumping in uncased wells can effectively provide a continuous vertical distribution of K in consolidated rocks. However, relatively few studies have used the flowmeter in screened wells penetrating unconsolidated aquifers, and tests conducted in gravel-packed wells have shown that flowmeter data may yield misleading results. This paper describes the practical application of flowmeter profiles in direct-push wells to measure K and delineate hydrofacies in heterogeneous unconsolidated aquifers having low-to-moderate K (10(-6) to 10(-4) m/s). The effect of direct-push well installation on K measurements in unconsolidated deposits is first assessed based on the previous work indicating that such installations minimize disturbance to the aquifer fabric. The installation and development of long-screen wells are then used in a case study validating K profiles from flowmeter tests at high-resolution intervals (15 cm) with K profiles derived from multilevel slug tests between packers at identical intervals. For 119 intervals tested in five different wells, the difference in log K values obtained from the two methods is consistently below 10%. Finally, a graphical approach to the interpretation of flowmeter profiles is proposed to delineate intervals corresponding to distinct hydrofacies, thus providing a method whereby both the scale and magnitude of K contrasts in heterogeneous unconsolidated aquifers may be represented.     

Multivariate statistical analysis of geochemical data as indicative of the hydrogeochemical evolution of groundwater in a sedimentary rock aquifer system

The study of groundwater hydrogeochemistry of the Paleozoic Basses-Laurentides sedimentary rock aquifer system in Québec produced a large geochemical dataset. Groundwater samples were collected at 153 sites over a 1500 km² study area and analyzed for major and minor ions. The large number of data can lead to difficulties in the integration, interpretation and representation of the results. Two multivariate statistical methods, hierarchical cluster analysis (HCA) and principal components analysis (PCA), were applied to a subgroup of the dataset to evaluate their usefulness to classify the groundwater samples, and to identify geochemical processes controlling groundwater geochemistry. This subgroup consisted of 144 samples and 14 parameters (Ca²⁺, Mg²⁺, Na⁺, K⁺, , Cl⁻, , Fe²⁺, Mn²⁺, Br⁻, Sr²⁺, F⁻, Ba²⁺, HS⁻). Seven geochemically distinct clusters, C1–C7, resulted from the HCA. Samples from clusters C3, C4, C6 and C7 are mostly located in preferential recharge areas. The majority of these samples have Ca–Mg–HCO₃ recharge groundwater (C3, C6, C7) and Na–HCO₃ evolved groundwater (C4). Samples from the other three clusters (C1, C2, C5) are characteristic of an aquifer system under confined conditions. The majority of these samples have Na–HCO₃ evolved groundwater (C1, C5) and Na–Cl ancient groundwater that exhibits elevated concentrations in Br⁻ (C2). In addition to recognizing the importance of hydrogeological conditions on groundwater geochemistry, the distribution of clusters also showed the importance of the geological formations on minor and trace elements, such as Fe²⁺, Mn²⁺, Sr²⁺, F⁻ and Ba²⁺. The first five components of the PCA account for 78.3% of the total variance in the dataset. Component 1 is defined by highly positive loadings in Na⁺, Cl⁻ and Br⁻ and is related to groundwater mixing with Champlain Sea water and solute diffusion from the marine clay aquitard. The high positive loadings in Ca²⁺ and Mg²⁺ of component 2 suggest the importance of dissolution of carbonate rocks in this aquifer system. From their characteristic loadings, the first two components are defined as the “salinity” and “hardness” components, respectively. Components 3–5 are related to more local and geological effects. The integration of the HCA and the PCA, with conventional classification of groundwater types, as well as with the hydrogeological and geological contexts, allowed the division of the region into four main geochemical areas, providing an improved regional picture of the aquifer system dynamics and hydrogeochemical evolution of groundwater. The following factors were recognized as influencing the evolution of groundwater identified in every geochemical area: (1) geological characteristics including sedimentary rock type and till mineralogy; (2) hydrogeological characteristics represented by the level of confinement and the hydraulic gradient; and (3) the geological history including the latest glaciation and the Champlain Sea invasion. With its integrated approach, this hydrogeochemical study contributes to the characterization and understanding of complex groundwater flow systems, and provides an example of the long-term geochemical evolution of hydrogeological systems after a major perturbation, in this case seawater invasion.     

Variability of the solar shape (before space dedicated missions)

Shrinking or expansion of the solar shape and irradiance variations are ultimately related to solar activity. We give here a review on existing ground-based or space solar radius measurements, extending the concept to shape changes. We show how helioseismology results allow us to look at the variations below the surface, where changes are not uniform, putting in evidence a new shallow layer, the leptocline, which is the seat of solar asphericities, radius variations with the 11-yr cycle and the cradle of complex physical processes: partial ionization of the light elements, opacities changes, superadiabaticity, strong gradient of rotation and pressure. Based on such physical grounds, we show why it is important to get accurate measurements from scheduled dedicated space missions: PICARD, SDO, DynaMICCS, ASTROMETRIA, SPHERIS. Such measurements will provide us a unique opportunity to study in detail the relationship between global solar properties and changes in the Sun's interior.     

The Comparison of δ<Superscript>13</Superscript>C Values of a Deposit- and a Suspension-Feeder Bio-Indicates Benthic vs. Pelagic Couplings and Trophic Status in Contrasted Coastal Ecosystems

δ¹³C and δ¹⁵N values of two generalists primary consumers, a strict deposit-feeder polychaete (Arenicola marina), and a strict suspension-feeder bivalve (Crassostrea gigas), were investigated to typify the trophic functioning of two contrasted marine coastal ecosystems (eutrophic and mesotrophic, east and west Cotentin peninsula, respectively, English Channel, Normandy, France). On average, δ¹³C and δ¹⁵N values of lugworms mirrored those of sediment organic matter (SOM), whereas δ¹³C and δ¹⁵N of oysters mirrored those of suspended particulate organic matter (SPOM). δ¹³C values of the two species displayed significant differences on the west coast (mesotrophic) contrary to the east coast (eutrophic; significant interactions). δ¹⁵N values differed only between sites and not between species. Diet of A. marina relied exclusively on microphytobenthos (MPB) and detritus of macroalgae (ULV) on the mesotrophic coast, whereas diet of C. gigas relied mainly on SPOM. Conversely, on the eutrophic ecosystem (the east coast), both species displayed the same diet, which was a mixture of pelagic sources (SPOM), benthic sources (MPB and ULV) and to a lesser extent riverine particulate organic matter (rPOM). These results were explained by the intensity of benthic vs. pelagic couplings (i.e. benthic-pelagic and pelagic-benthic) which differed in the two ecosystems. Low trophic coupling occurred on the mesotrophic (west) coast, whereas benthic-pelagic (SOM resuspension) and pelagic-benthic (settling of SPOM such as phytoplankton blooms) couplings were typified on the eutrophic (east) coast. This higher particulate organic matter (POM) pelagic-benthic coupling on the east coast was probably enhanced by nutrient enrichment caused by eutrophication. Comparison of δ¹³C ratios of both the strict deposit-feeder (e.g. A. marina) and the strict suspension-feeder (e.g. C. gigas) was then proposed as a bio-indicator of the trophic status and of POM benthic vs. pelagic couplings of soft-bottom coastal ecosystems.