The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Leszek Starkel - One of the best experts on this subject based on the ideXlab platform.
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younger dryas preboreal transition documented in the Fluvial Environment of polish rivers
Global and Planetary Change, 2003Co-Authors: Leszek StarkelAbstract:Abstract The rapid climatic change at the Younger Dryas–Preboreal transition has been documented in the sequence of annually laminated sediments of Lake Gościąz in the middle course of the Vistula Valley. The author correlates this key profile with about 50 localities of alluvial sediments and abandoned channels in the Vistula and Warta catchments. Discussed deposits have been radiocarbon-dated. The interpretation is supported by pollen diagrams. It is concluded that in most cases, either abundance of large paleochannels or a change from channel to overbank facies or to organic sedimentation took place just at the transition time. Also, in the fills of the Late glacial paleochannels, a decline in Fluvial activity is observed that is evidenced by a change in grain size composition. However, an exact dating of this rapid transition is difficult as it coincides with the radiocarbon plateau at 10 ka BP.
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Younger Dryas–Preboreal transition documented in the Fluvial Environment of Polish rivers
Global and Planetary Change, 2002Co-Authors: Leszek StarkelAbstract:Abstract The rapid climatic change at the Younger Dryas–Preboreal transition has been documented in the sequence of annually laminated sediments of Lake Gościąz in the middle course of the Vistula Valley. The author correlates this key profile with about 50 localities of alluvial sediments and abandoned channels in the Vistula and Warta catchments. Discussed deposits have been radiocarbon-dated. The interpretation is supported by pollen diagrams. It is concluded that in most cases, either abundance of large paleochannels or a change from channel to overbank facies or to organic sedimentation took place just at the transition time. Also, in the fills of the Late glacial paleochannels, a decline in Fluvial activity is observed that is evidenced by a change in grain size composition. However, an exact dating of this rapid transition is difficult as it coincides with the radiocarbon plateau at 10 ka BP.
V. Torres - One of the best experts on this subject based on the ideXlab platform.
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Late Eocene marine incursion in north-western South America
Palaeogeography Palaeoclimatology Palaeoecology, 2008Co-Authors: C. Santos, Milton Rueda, Germán Bayona, Carlos Jaramillo, V. TorresAbstract:ARTICLE I NFO During the late Eocene in the Colombian Subandean basins, one of the most important oil-bearing rocks of the country was deposited: the Mirador Formation. Palaeogeographical models have interpreted a typically Fluvial Environment for the lower Mirador Formation and marginal to marine Environments for its upper layers. The potential of marine influence in the upper Mirador beds and the overlying lower Carbonera formation as a correlation tool, and the palaeogeographic distribution of the event have not yet been defined. In order to determine the palaeogeography of this probable incursion, 80 wells and four sections were analysed using palynological techniques. The presence of a marine influence in the sediments was determined by using a Salinity Index (SI) that describes the negative relationship between continental and marine palynomorphs. The marine influence has been recognized in two areas: the first, in the Putumayo basin, and the second, in the Eastern Cordillera and Central Llanos Foothills. In the Putumayo basin the Salinity Index pattern reveals a southern provenance of the marine incursion, flooding the Colombian territory in a South-North trend through the Ecuadorian coast. The marine influence of the Eastern Cordillera and the Central-Eastern Llanos Foothills is more difficult to explain. We propose a possible corridor through the proto-Lower Magdalena Valley that connected the Caribbean Sea and the Central Llanos Foothills. Palaeogeographic models for the late Eocene of north-western South America should consider this marine incursion and its geographical distribution. Published by Elsevier B.V.
Gerardo Benito - One of the best experts on this subject based on the ideXlab platform.
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Late Holocene Fluvial chronology of Spain: The role of climatic variability and human impact
Catena, 2006Co-Authors: Varyl R. Thorndycraft, Gerardo BenitoAbstract:Abstract A database of published and unpublished radiocarbon dates from Late Holocene Fluvial Environments in Spain was critically analysed in order to obtain a Fluvial chronology for this period. The principal types of depositional Environment represented in the record were slackwater flood deposits (28 dates), alluvial overbank facies (12 dates) and alluvial channel facies (7 dates). The sedimentary context of each date was classified in order to identify those samples that specifically dated change in the Fluvial Environment. Analysis of the different depositional Environment data-sets using summed probability plots identified phases of alluviation at 2800–2350 and 800–500 cal. BP. Increased frequency of large magnitude floods occurred at 2850–2500, 1000–800 and 520–250 cal. BP. The results indicate that in Mediterranean regions slackwater flood deposits are valuable archives of climatic variability even during periods of increased human impact.
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Late Holocene Fluvial chronology of Spain: The role of climatic variability and human impact
CATENA, 2006Co-Authors: Varyl R. Thorndycraft, Gerardo BenitoAbstract:A database of published and unpublished radiocarbon dates from Late Holocene Fluvial Environments in Spain was critically analysed in order to obtain a Fluvial chronology for this period. The principal types of depositional Environment represented in the record were slackwater flood deposits (28 dates), alluvial overbank facies (12 dates) and alluvial channel facies (7 dates). The sedimentary context of each date was classified in order to identify those samples that specifically dated change in the Fluvial Environment. Analysis of the different depositional Environment data-sets using summed probability plots identified phases of alluviation at 2800–2350 and 800–500 cal. BP. Increased frequency of large magnitude floods occurred at 2850–2500, 1000–800 and 520–250 cal. BP. The results indicate that in Mediterranean regions slackwater flood deposits are valuable archives of climatic variability even during periods of increased human impact.This research was funded by the International Council for Science (ICSU) project “Past hydrological events related to understanding global change” and the INQUA project “The significance of past hydrological events: using existing 14C data to reconstruct Holocene Fluvial activity in temperate and tropical regions.”Peer reviewe
C. Santos - One of the best experts on this subject based on the ideXlab platform.
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Late Eocene marine incursion in north-western South America
Palaeogeography Palaeoclimatology Palaeoecology, 2008Co-Authors: C. Santos, Milton Rueda, Germán Bayona, Carlos Jaramillo, V. TorresAbstract:ARTICLE I NFO During the late Eocene in the Colombian Subandean basins, one of the most important oil-bearing rocks of the country was deposited: the Mirador Formation. Palaeogeographical models have interpreted a typically Fluvial Environment for the lower Mirador Formation and marginal to marine Environments for its upper layers. The potential of marine influence in the upper Mirador beds and the overlying lower Carbonera formation as a correlation tool, and the palaeogeographic distribution of the event have not yet been defined. In order to determine the palaeogeography of this probable incursion, 80 wells and four sections were analysed using palynological techniques. The presence of a marine influence in the sediments was determined by using a Salinity Index (SI) that describes the negative relationship between continental and marine palynomorphs. The marine influence has been recognized in two areas: the first, in the Putumayo basin, and the second, in the Eastern Cordillera and Central Llanos Foothills. In the Putumayo basin the Salinity Index pattern reveals a southern provenance of the marine incursion, flooding the Colombian territory in a South-North trend through the Ecuadorian coast. The marine influence of the Eastern Cordillera and the Central-Eastern Llanos Foothills is more difficult to explain. We propose a possible corridor through the proto-Lower Magdalena Valley that connected the Caribbean Sea and the Central Llanos Foothills. Palaeogeographic models for the late Eocene of north-western South America should consider this marine incursion and its geographical distribution. Published by Elsevier B.V.
Szilard Szabo - One of the best experts on this subject based on the ideXlab platform.
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aerial laser scanning data as a source of terrain modeling in a Fluvial Environment biasing factors of terrain height accuracy
Sensors, 2020Co-Authors: Z Szabo, Csaba Toth, I J Holb, Szilard SzaboAbstract:Airborne light detection and ranging (LiDAR) scanning is a commonly used technology for representing the topographic terrain. As LiDAR point clouds include all surface features present in the terrain, one of the key elements for generating a digital terrain model (DTM) is the separation of the ground points. In this study, we intended to reveal the efficiency of different denoising approaches and an easy-to-use ground point classification technique in a floodplain with Fluvial forms. We analyzed a point cloud from the perspective of the efficiency of noise reduction, parametrizing a ground point classifier (cloth simulation filter, CSF), interpolation methods and resolutions. Noise filtering resulted a wide range of point numbers in the models, and the number of points had moderate correlation with the mean accuracies (r = −0.65, p < 0.05), indicating that greater numbers of points had larger errors. The smallest differences belonged to the neighborhood-based noise filtering and the larger cloth size (5) and the smaller threshold value (0.2). The most accurate model was generated with the natural neighbor interpolation with the cloth size of 5 and the threshold of 0.2. These results can serve as a guide for researchers using point clouds when considering the steps of data preparation, classification, or interpolation in a flat terrain.