Search results for "PLE"
showing 10 items of 22773 documents
Evaluating ice fabrics using fabric analyser techniques in Sørsdal Glacier, East Antarctica
2011
AbstractIce cores (∼4 m long) obtained from areas of different surface velocities near the terminus of Sørsdal Glacier, East Antarctica, have been investigated using two versions of a fabric analyser (G50). In sections parallel to the flow plane, the microstructure is typically interlocking with elongate grains that parallel air-bubble elongation, X, reflecting their development in an earlier ductile regime. The c-axis fabric patterns vary with respect to X and vary from single–double maxima to asymmetric small-circle girdles oblique to the planar foliation, which can be attributed to a simple shear regime. The siteto-site variations in the c-axis patterns can be related to areas of differe…
Sandy fan‐like forms in the central‐eastern mazovian lowland (central poland): textural record and chronology
2016
A unique, continuous, fan-shaped belt of sandy landforms in the central-eastern Mazovian Lowland, Central Poland has been investigated using a multiproxy dataset of sediment physical properties and chronological framework. Although there are several previous studies of similar fan-like forms elsewhere in Central Poland, this central-eastern part has not been investigated in detail. A combined methodological approach, using grain-size distributions, the roundness, surface character and microtexture of quartz grains, and the mineral composition of the light and heavy fractions, indicate a predominantly aeolian origin for the fan-like forms. Overlying them are dunes, the sediment within which …
Missing Records and Depositional Breaks in French Late Pleistocene Cave Sediments
1993
AbstractCave entrance and rock shelter infillings are positioned within the Pleistocene chronology for three areas of France (northern Alps, Franche-Comté, and Périgord). Despite minor local variations, it is possible to identify regional types with a consistent depositional record over long intervals of time. The interregional variability relates to the frequency and position of the gaps within the infillings. Sites in the northern Alps have not yielded any artifacts older than the Upper Paleolithic (Magdalenı́an), and dated sedimentary sequences do not go back beyond the Older Dryas. More complete sequences in Franche-Comté contain Mousterian industries. Two major gaps occur here, one las…
Breaking the waves: Human use of marine bivalves in a microtidal range coast during the Upper Pleistocene and the Early Holocene, Vestíbulo chamber, …
2016
Abstract This paper presents the results obtained from the study of the bivalves recovered during the archaeological excavations in the Vestibulo chamber of Nerja Cave (Malaga, southern Spain) carried out by Professor Francisco Jorda Cerda between 1983 and 1987. These excavations recovered the archaeological record of the sequence from the Gravettian to the Neolithic. The mollusc remains from the Vestibulo chamber of Nerja Cave record constitute an extraordinary collection, composed of more than 136000 specimens which correspond to more than 78 kg. In this work, only marine bivalves were studied. The bivalve remains are more than 124000 specimens, corresponding to more than 65 kg from 31 ta…
Paleoclimatic evolution of the Uvs Nuur basin and adjacent areas (Western Mongolia)
2000
Abstract The investigations presented in this paper focus on the shifts in Pleistocene glaciations and the geomorphic changes in landforms, as well as lake level changes and aeolian deposits of the last glacial–interglacial cycle, including the Holocene. Geomorphic evidence and high lake levels show that the climate was more humid before the last glacial maximum (LGM); however, at least one arid phase also occurred. During the second half of the LGM the climate was dry and cold, turning to wet and cold during the Late Glacial of the last Ice Age. Fluctuations in humidity and temperature occurred during the Holocene. Since about 2000 yr BP the impact of human activity has increased.
Speleothems from the Middle East: An Example of Water Limited Environments in the SISAL Database
2019
The Middle East (ME) spans the transition between a temperate Mediterranean climate in the Levant to hyper-arid sub-tropical deserts in the southern part of the Arabian Peninsula (AP), with the complex alpine topography in the northeast feeding the Euphrates and Tigris rivers which support life in the Southeastern Fertile Crescent (FC). Climate projections predict severe drying in several parts of the ME in response to global warming, making it important to understand the controls of hydro-climate perturbations in the region. Here we discuss 23 ME speleothem stable oxygen isotope (δ18Occ) records from 16 sites from the SISAL_v1 database (Speleothem Isotope Synthesis and Analysis database), …
Soil physicochemical and microbial drivers of temperature sensitivity of soil organic matter decomposition under boreal forests
2020
Abstract Soil organic matter (SOM) in boreal forests is an important carbon sink. The aim of this study was to assess and to detect factors controlling the temperature sensitivity of SOM decomposition. Soils were collected from Scots pine, Norway spruce, silver birch, and mixed forests (O horizon) in northern Finland, and their basal respiration rates at five different temperatures (from 4 to 28 °C) were measured. The Q10 values, showing the respiration rate changes with a 10 °C increase, were calculated using a Gaussian function and were based on temperature-dependent changes. Several soil physicochemical parameters were measured, and the functional diversity of the soil microbial communit…
Carbon sequestration potential of Italian orchards and vineyards
2017
From 2004 to 2012 carbon (C) fluxes between the soil-vegetation system and the atmosphere in apple, grape, olive and orange orchards planted in different Italian regions were measured. Above-ground net primary productivity (ANPP) ranged from 4 (olive) to 9 (apple) Mg C ha-1. Alley grass contribution to total ANPP significantly varied among the systems, reaching a maximum of 60% in vineyards. The harvest index ranged from 46% for apple, to 58% for orange, 60% for grape and 41% for olive, while abscised leaves accounted for 30% of ANPP, on average. Soil respiration fluxes ranged from 6 (orange) to 10 (grape) Mg C ha-1. Results indicate the potential of these fruit crop to sequester atmospheri…
More is more? : Forest management allocation at different spatial scales to mitigate conflicts between ecosystem services
2017
Context: Multi-objective management can mitigate conflicts among land-use objectives. However, the effectiveness of a multi-objective solution depends on the spatial scale at which land-use is optimized. This is because the ecological variation within the planning region influences the potential for site-specific prioritization according to the different objectives. Objectives: We optimized the allocation of forest management strategies to maximize the joint production of two conflicting objectives, timber production and carbon storage, at increasing spatial scales. We examined the impacts of the extent of the planning region on the severity of the conflict, the potential for its mitigation…
Mn/Ca in shells of Arctica islandica (Baltic Sea) – A potential proxy for ocean hypoxia?
2021
Oxygen depletion threatens an increasing number of shallow water environments, specifically habitats below the seasonal halocline in coastal settings of the Baltic Sea. To understand the natural variations of dissolved oxygen levels on seasonal and inter-annual time-scales prior to the instrumental era, high-resolution archives are urgently required. The present study evaluates the potential use of Mn/Ca values in shells of the bivalve, Arctica islandica to infer concentrations of past dissolved oxygen concentrations. This study is based on laser ablation – inductively coupled plasma – mass spectrometry (LA-ICP-MS) data of six contemporaneous specimens and demonstrates that background varia…