Search results for "PROCESSES"
showing 10 items of 3831 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…
A review of climate reconstructions from terrestrial climate archives covering the first millennium AD in northwestern Europe
2018
AbstractLarge changes in landscape, vegetation, and culture in northwestern (NW) Europe during the first millennium AD seem concurrent with climatic shifts. Understanding of this relation requires high-resolution palaeoclimate reconstructions. Therefore, we compiled available climate reconstructions from sites across NW Europe (extent research area: 10°W–20°E, 45°–60°N) through review of literature and the underlying data, to identify supraregional climatic changes in this region. All reconstructions cover the period from AD 1 to 1000 and have a temporal resolution of ≤50 yr. This resulted in 22 climate reconstructions/proxy records based on different palaeoclimate archives: chironomids (1)…
The early Upper Palaeolithic of Cova de les Cendres (Alicante, Spain)
2019
Abstract This paper presents a synthesis of the Early Upper Palaeolithic of Cova de les Cendres. Points of special attention are the sedimentary and micromorphological characterisation of level XVI, the analysis of the vegetal and animal resources and their incidence on the economy of the Gravettian human groups, and the characterisation of the landscape during this period. Furthermore, the paper offers important information of the lithic and bone assemblages, economic behaviour and radiocarbon dates of sub-levels XVIA and XVIB, related to the Gravettian, and XVIC and XVID, corresponding to the Aurignacian. Finally, the Gravettian and Aurignacian regional contexts in the Mediterranean Basin…
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…
Landscape reconstruction and major flood events of the River Main (Hesse, Germany) in the environs of the Roman fort at Groβkrotzenburg
2020
Abstract Detailed geoarchaeological studies were conducted at the Groβkrotzenburg floodplain (Southern Hesse, Germany) in order to reconstruct the fluvial palaeogeography and search for Roman harbour installations. Another objective was to reconstruct the local flood history based on stratigraphic and geochronological data. Prospection based on electrical resistivity tomography, vibracoring and direct push electrical conductivity logging were carried out to detect and analyze subsurface stratigraphies. Altogether, 6 sediment cores, up to 7 m long, were drilled along transects along and perpendicular to the present course of the River Main. Based on sedimentological and geochemical data, we …
Does glacial environment produce glacial mineral grains? Pro- and supra-glacial Icelandic sediments in microtextural study
2022
Abstract Mineral grains from proglacial and supraglacial sedimentary settings in central south-eastern Iceland are considered in this study and analysed with the use of scanning electron microscope (SEM) techniques. By applying this, it is attempted to answer the key research question of whether quartz grains that come from a glacial-related sedimentary environment are indeed of glacial origin. The study also attempts to provide a linkage between microtextures produced on coarser and finer grains and to verify whether mineral grains from adjacent cryconite holes are similar or different. The preliminary assumption was that the more intense glacial grain record was based on several glacial a…
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.
Accelerated transgressive processes in a Mediterranean coastal barrier: Subsidence, anthropic action and geomorphological changes since the Little Ic…
2020
Abstract Subsidence, changes in sediment supply and environments, sea storms, current sedimentary deficit and recent anthropic action are factors determining coastal geomorphological processes and evolution of a transgressive Mediterranean coastal barrier. At a longer timescale, the barrier landward migration is partially due to local subsidence of tectonic origin. Peatmarsh remains under seawater at around 100 m from the present-day coastline (4821–4566 and 4874‒4820 cal BP) show evidence of the more advanced position towards the sea of the late Holocene coastal barrier, which has not been preserved. Furthermore, behind the present gravel barrier, wide sandy washover fans dating about 665 …