820 resultados para outcrop


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Pollen analyses and 14C-datings were carried out on two late glacial profiles from Ruegen Island, Mecklenburg-Vorpommern at the southwestern Baltic coast. The palaeoclimatic and palaeoecologic interpretations were supported by carpological investigations. The organogenic deposits of the 'Hoelle' outcrop near Dwasieden Park were chosen because of their unique stratigraphic position, which according to PANZIG (1989), lay under a m3m-Glacial Till of the Mecklenburg Advance (W3). The results indicated that the initial phase of the late glacial sedimentation in a relatively small and asymmetrical lake basin (in comparison with the larger Nieder- and Credner lake to the southwest), probably had its origin in the older Alleroed (II a) after FIRBAS (1949). The basal clastic sediments were rapidly followed by peat deposits and later, due to a rising water table, by muds rich in organic matter. The area was covered with sparse Betula-(Pinus) forests having heliophilous late-glacial elements typical of the surrounding areas during the younger Alleroed (II b). With the climatic change to colder and drier conditions at the beginning of the Younger Dryas (III), the vegetation decreased and enhanced erosional processes led to the fill up of the depression with fine clastic sediments. The intense relief differences of the surroundings coupled with high water saturation in the sediments led to solifluction in the m3m-Glacial Till and its placement discordantly over the organogenic sequence.

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This data set presents a comprehensive characterisation of the sedimentary structures from important groundwater hosting formations in Germany (Herten aquifer analog) and Brazil (Descalvado aquifer analog). Multiple 2-D outcrop faces are described in terms of hydraulic, thermal and chemical properties and interpolated in 3D using stochastic techniques. For each aquifer analog, multiple 3D realisations of the facies heterogeneity are provided using different stochastic simulations settings. These are unique analogue data sets that can be used by the wider community to implement approaches for characterising aquifer formations.

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A wide variety of environmental records is necessary for analysing and understanding the complex Late Quaternary dynamics of permafrost-dominated Arctic landscapes. A NE Siberian periglacial key region was studied in detail using sediment records, remote sensing data, and terrain modelling, all incorporated in a geographical information system (GIS). The study area consists of the Bykovsky Peninsula and the adjacent Khorogor Valley in the Kharaulakh Ridge situated a few kilometres southeast of the Lena Delta. In this study a comprehensive cryolithological database containing information from 176 sites was compiled. The information from these sites is based on the review of previously published borehole data, outcrop profiles, surface samples, and our own field data. These archives cover depositional records of three periods: from Pliocene to Early Pleistocene, the Late Pleistocene and the Holocene. The main sediment sequences on the Bykovsky Peninsula consist of up to 50 m thick ice-rich permafrost deposits (Ice Complex) that were accumulated during the Late Pleistocene. They were formed as a result of nival processes around extensive snowfields in the Kharaulakh Ridge, slope processes in these mountains (such as in the Khorogor Valley), and alluvial/proluvial sedimentation in a flat accumulation plain dominated by polygonal tundra in the mountain foreland (Bykovsky Peninsula). During the early to middle Holocene warming, a general landscape transformation occurred from an extensive Late Pleistocene accumulation plain to a strongly thermokarst-dominated relief dissected by numerous depressions. Thermokarst subsidence had an enormous influence on the periglacial hydrological patterns, the sediment deposition, and on the composition and distribution of habitats. Climate deterioration, lake drainage, and talik refreezing occurred during the middle to late Holocene. The investigated region was reached by the post-glacial sea level rise during the middle Holocene, triggering thermo-abrasion of ice-rich coasts and the marine inundation of thermokarst depressions.

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