Contributors:Anxin Lu, Yang Gao, Yanbin Lei, Yang Xiang, Pablo Iribarren Anacona, Shenghai Li, Weicai Wang, Guoqing Zhang
Glacial lake outburst floods (GLOFs) have recently become one of the primary natural hazards in the Himalayas. There is therefore an urgent need to assess GLOF hazards in the region. Cirenmaco, a moraine-dammed lake located in the upstream portion of Zhangzangbo valley, Central Himalayas, has received public attention after its damaging 1981 outburst flood. Here, by combining remote sensing methods, bathymetric survey and 2D hydraulic modeling, we assessed the hazard posed by Cirenmaco in its current status. Inter-annual variation of Cirenmaco lake area indicates a rapid lake expansion from 0.10±0.08km2 in 1988 to 0.39±0.04km2 in 2013. Bathymetric survey shows the maximum water depth of the lake in 2012 was 115±2m and the lake volume was calculated to be 1.8×107m3. Field geomorphic analysis shows that Cirenmaco glacial lake is prone to GLOFs as mass movements and ice and snow avalanches can impact the lake and the melting of the dead ice in the moraine can lower the dam level. HEC-RAS 2D model was then used to simulate moraine dam failure of the Cirenmaco and assess GLOF impacts downstream. Reconstruction of Cirenmaco 1981 GLOF shows that HEC-RAS can produce reasonable flood extent and water depth, thus demonstrate its ability to effectively model complex GLOFs. GLOF modeling results presented can be used as a basis for the implementation of disaster prevention and mitigation measures. As a case study, this work shows how we can integrate different methods to GLOF hazard assessment.
Contributors:Mariela E. González, María C. Álvarez, Cristian A. Kaufmann, Agustina Massigoge, María A. Gutiérrez, Nahuel A. Scheifler, Daniel J. Rafuse
Inspired by the early fieldwork of G. Haynes with large sized predators in wilderness areas, the following paper presents data on bone damage patterns in a sample of guanacos killed by one of the largest predators in South America, the puma (Puma concolor, Felidae, Carnivora). We describe the bone modification pattern on the carcasses, including skeletal part representation, bone fractures, and tooth marks. Also, tooth mark modifications on bones collected from a puma enclosure at a local zoo were analyzed. Our results indicate a light modification of guanaco carcass by puma; bone damages located mainly in the upper portions of rear and forelimbs, rib cage, and scapular and pelvic girdles; and the presence of a low percentage of fractured bones. Scores, pits, and punctures are the best represented tooth marks. On average, punctures are 3.5–5 mm in diameter, although larger tooth impressions are observed. The light consumption of guanaco by the puma would provide a potential source for scavenging by other carnivores and humans.
Contributors:Marco Cavalli, Francesco Comiti, Francesco Brardinoni, Lorenzo Marchi, Beatrice Goldin
Digital elevation models (DEMs) built from repeated topographic surveys permit producing DEM of Difference (DoD) that enables assessment of elevation variations and estimation of volumetric changes through time. In the framework of sediment transport studies, DEM differencing enables quantitative and spatially-distributed representation of erosion and deposition within the analyzed time window, at both the channel reach and the catchment scale. In this study, two high-resolution Digital Terrain Models (DTMs) derived from airborne LiDAR data (2m resolution) acquired in 2005 and 2011 were used to characterize the topographic variations caused by sediment erosion, transport and deposition in two adjacent mountain basins (Gadria and Strimm, Vinschgau - Venosta valley, Eastern Alps, Italy). These catchments were chosen for their contrasting morphology and because they feature different types and intensity of sediment transfer processes. A method based on fuzzy logic, which takes into account spatially variable DTMs uncertainty, was used to derive the DoD of the study area. Volumes of erosion and deposition calculated from the DoD were then compared with post-event field surveys to test the consistency of two independent estimates. Results show an overall agreement between the estimates, with differences due to the intrinsic approximations of the two approaches. The consistency of DoD with post-event estimates encourages the integration of these two methods, whose combined application may permit to overcome the intrinsic limitations of the two estimations. The comparison between 2005 and 2011 DTMs allowed to investigate the relationships between topographic changes and geomorphometric parameters expressing the role of topography on sediment erosion and deposition (i.e., slope and contributing area) and describing the morphology influenced by debris flows and fluvial processes (i.e., curvature). Erosion and deposition relations in the slope-area space display substantial differences between the Gadria and the Strimm basins. While in the former erosion and deposition clusters are reasonably well discriminated, in the latter, characterized by a complex stepped structure, we observe substantial overlapping. Erosion mostly occurred in areas that show persistency of concavity or transformation from convex and flat to concave surfaces, whereas deposition prevailingly took place on convex morphologies. Less expected correspondences between curvature and topographic changes can be explained by the variable sediment transport processes, which are often characterized by alternation of erosion and deposition between different events and even during the same event.
This paper aims to further our understanding of pre-Columbian agricultural systems in the Llanos de Moxos, Bolivia. Three different types of raised fields co-existing in the same site near the community of Exaltación, in north-western Beni, were studied. The morphology, texture and geochemistry of the soils of these fields and the surrounding area were analysed. Differences in field design have often been associated with the diversity of cultural practices. Our results suggest that in the study area differences in field shape, height and layout are primarily the result of an adaptation to the local edaphology. By using the technology of raised fields, pre-Columbian people were able to drain and cultivate soils with very different characteristics, making the land suitable for agriculture and possibly different crops. This study also shows that some fields in the Llanos de Moxos were built to prolong the presence of water, allowing an additional cultivation period in the dry season and/or in times of drought. Nevertheless, the nature of the highly weathered soils suggests that raised fields were not able to support large populations and their management required long fallow periods.
Contributors:Atindra Sapkota, Ji Shen, Kunshan Bao
The objectives of this study were to determine the concentrations and accumulation rates of trace metals in the Yancheng coastal wetland of Jiangsu province, China, and to assess their relationship to establish a history of anthropogenic metal emissions. To address these aims, we analyzed 26 major and trace elements using ICP-AES and ICP-MS in two sediment sections dated by 210Pb and 137Cs techniques (approximately spanning the last 150years). Physicochemical parameters including bulk density, water content, mass magnetic susceptibility and grain-size composition were also documented. The relationship between these factors was examined through a correlation analysis, and two principal components were discriminated by a principal component analysis (PCA) based on eigen-values>1 and explaining 85% of the total variance of the element concentrations: the first component covering As, Cd, Pb, Sb and Zn is associated with an anthropogenic source, and the second component representing Al, Cu, K, Rb, and Sr reflects a lithogenic source. The first group also includes Fe and Mn and probably reflects the influence of the redox status during the geochemical process. The accumulation rates and enrichment factors of the trace metals suggest an increasing pollution pattern, especially for the last 20years. The reconstructed history of trace metal pollution over the past 150years is consistent with the industrial development in Jiangsu province and clearly illustrates the influence of human activities on the local environment. This high resolution geochemical dataset for the Yancheng coastal wetland is helpful for understanding the deposition processes and reconstructing the past pollution history from anthropogenic activities in the area.
Contributors:Rafael Mora Torcal, Jorge Martínez-Moreno, Alfonso Benito-Calvo, Fco. Javier Plasencia Figueroa, Miquel Roy Sunyer
The exploitation of rocks from secondary deposits is attested widely in the European Middle Palaeolithic. However, few studies have focused on analysing the implications derived from the management of these deposits. The fluvial terraces near the Mousterian site of Roca dels Bous have been sampled to determine their lithological composition and cobble morphology. Comparison with artefacts recovered from level N12 indicate selection patterns in the fluvial deposits of black quartzite, as well as preferential management of blanks with specific morphological and volumetric characteristics. This approach reveals behaviours involved in the acquisition, transport, transformation and discard of stone tools necessary for Neanderthal subsistence, and indicates interest in the study of secondary deposits and local raw materials in Middle Palaeolithic contexts.
The archaeological materials from Kůlna Cave have undergone various types of analyses as part of many different studies. Some of these have indicated the need to carry out a reconstruction of the spatial distribution of finds in order to focus on the ways in which the cave was divided. Having such knowledge, we could also explain more precisely the function of individual settlement horizons. The system of documentation, employed during the excavation of the cave, has made it difficult to analyse the spatial distributions using conventional methods. It is proposed using of GIS software spatial analysis simulations brought relevant and evident visualization. The results show that the utilisation of the cave changed with time. Along with simple structures attributed to the Taubachian, we also describe evidence of complex use of the interior of Kůlna Cave during the Micoquian phase of settlement (around 50 ka calBP). Results of spatial distribution analyses indicate that the same functional division of the cave was maintained over time (e.g. layer 7a or 6a) and it consequently assumes a transmission of social knowledge within the organisation of the Kůlna Cave space.
Although the Early Pleistocene Sus lydekkeri has been uncovered from several localities in northern China, the fragmental state of the specimens results the discussion on its taxonomic status and its relationship with European Sus strozzii. A nearly complete skull with mandible was unearthed in situ from upper Nihewan Formation at the horizon paleomagnetically dated 1.6 Ma during the excavation conducted in 2013 at Yangshuizhan in the Nihewan Basin in North China. The skull is better preserved than that from the Middle Pleistocene of the Peking Man Site, the type locality of S. lydekkeri. As the best preserved skull of S. lydekkeri, it bears some key characters previously little known, e.g. the developed canine flange, small and flattened tympanic bulla, and rather weak hamulus pterygoideus of pterygoid. The morphology and metric analyses show that the material from Nihewan belongs to S. lydekkeri instead of S. strozzii and the latter is a distinct species different from S. lydekkeri. The interaction between early human and suid started at least as early as the Early Pleistocene based on the fact that S. lydekkeri is present in many early human or Palaeolithic sites.