The Experts below are selected from a list of 33 Experts worldwide ranked by ideXlab platform
Jørn Bo Jensen - One of the best experts on this subject based on the ideXlab platform.
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Late Quaternary sedimentary processes and ocean circulation changes at the Southeast Greenland margin
Marine Geology, 2003Co-Authors: Antoon Kuijpers, Simon Troelstra, Maarten A. Prins, K. Linthout, A Akhmetzhanov, S Bouryak, M.f Bachmann, S Lassen, S Rasmussen, Jørn Bo JensenAbstract:A study has been made of late Quaternary depositional processes and bottom current activity on the Southeast Greenland margin, using seismic, sub-bottom profiling and deep-tow side-scan sonar data as well as sediment core information. The seabed data demonstrate the occurrence of strong, southerly bottom currents prevailing on the slope and rise. Well-defined longitudinal bedforms indicate maximum mean near-bottom current velocities of up to at least 1.0 m/s at the depth stratum of Labrador Sea water (800–1500 m). Similarly strong currents occur in Denmark Strait overflow water (DSOW) at the base of the slope, whereas more basinward the maximum DSOW flow speed is lower. Iceberg plow marks were found down to about 700 m water depth. Both at the shelf edge and on the lower slope and rise the seafloor morphology is indicative of downslope sediment transport and mass flow deposition, which is concluded to be a typically Glacial Feature. After generally more sluggish deep-water circulation during the last Glacial maximum, DSOW basin ventilation was re-established shortly before 13.3 ka. On the shelf, in front of the retreating Greenland ice margin, permanent or semi-permanent sea ice conditions prevailed until about 12.5 ka. At that time increased Irminger Current activity had resulted in warming, and East Greenland Current (EGC)-controlled iceberg drift increased. No evidence was found for a return to extreme Glacial conditions or a ceasing of DSOW flow during the Younger Dryas. Abundant coarse IRD collected at greater water depth from shallow sub-seabed strata has a provenance mainly in the northern part of East Greenland (68–73°N), which demonstrates the existence of a pre-Holocene EGC system initially extending to beyond the shelf edge.
Régis Braucher - One of the best experts on this subject based on the ideXlab platform.
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Cosmogenic 10Be dating of ice sheet marginal belts in Mecklenburg-Vorpommern, Western Pomerania (northeast Germany)
Quaternary Geochronology, 2014Co-Authors: Vincent Rinterknecht, Andreas Börner, Didier Bourlès, Régis BraucherAbstract:Abstract Northeastern Germany was repeatedly covered by the Scandinavian Ice Sheet during the last glaciation and a succession of distinct ice marginal belts is present in Mecklenburg-Vorpommern. We used surface exposure dating to develop a time frame for the retreat of the ice margin. Two samples from the Saalian ice marginal belt give Weichselian ages, a problem that has also been encountered further south when attempting to date the same ice marginal belt (the Hoher Flaming) in Brandenburg. One sample from the Frankfurt moraine is too young to be associated with this Glacial Feature. Another single sample from the Velgast extent gives also an exposure age that is too young to be associated with this Glacial Feature. These two examples highlight the necessity to sample multiple boulders on the same Feature to obtain a reliable exposure age. Fourteen samples were collected on the Pomeranian moraine and 12 were used to calculate an average deposition time of 15.6 ± 0.6 10 Be kyr. Two samples were removed from the age distribution based on statistical grounds. This result is in good agreement with results obtained in Brandenburg where the Pomeranian moraine was dated at 16.4 ± 0.7 10 Be kyr. Five samples from the Mecklenburgian moraine give an average age of 13.7 ± 0.6 10 Be kyr in good chronological order with the Pomeranian moraine age. One sample (MVP-21) from the Mecklenburgian moraine was corrected for burial effect based on historical documents demonstrating that if known, the recent past history of exposure of a surface can be appropriately used to calculate an exposure age. Together, this new data set highlights: 1. the difficulty to date surfaces older than the Weichselian glaciation when using only one cosmogenic radionuclide, 2. the consistency of the results obtained for the Pomeranian moraine across northeastern Germany using cosmogenic Be-10.
Antoon Kuijpers - One of the best experts on this subject based on the ideXlab platform.
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Late Quaternary sedimentary processes and ocean circulation changes at the Southeast Greenland margin
Marine Geology, 2003Co-Authors: Antoon Kuijpers, Simon Troelstra, Maarten A. Prins, K. Linthout, A Akhmetzhanov, S Bouryak, M.f Bachmann, S Lassen, S Rasmussen, Jørn Bo JensenAbstract:A study has been made of late Quaternary depositional processes and bottom current activity on the Southeast Greenland margin, using seismic, sub-bottom profiling and deep-tow side-scan sonar data as well as sediment core information. The seabed data demonstrate the occurrence of strong, southerly bottom currents prevailing on the slope and rise. Well-defined longitudinal bedforms indicate maximum mean near-bottom current velocities of up to at least 1.0 m/s at the depth stratum of Labrador Sea water (800–1500 m). Similarly strong currents occur in Denmark Strait overflow water (DSOW) at the base of the slope, whereas more basinward the maximum DSOW flow speed is lower. Iceberg plow marks were found down to about 700 m water depth. Both at the shelf edge and on the lower slope and rise the seafloor morphology is indicative of downslope sediment transport and mass flow deposition, which is concluded to be a typically Glacial Feature. After generally more sluggish deep-water circulation during the last Glacial maximum, DSOW basin ventilation was re-established shortly before 13.3 ka. On the shelf, in front of the retreating Greenland ice margin, permanent or semi-permanent sea ice conditions prevailed until about 12.5 ka. At that time increased Irminger Current activity had resulted in warming, and East Greenland Current (EGC)-controlled iceberg drift increased. No evidence was found for a return to extreme Glacial conditions or a ceasing of DSOW flow during the Younger Dryas. Abundant coarse IRD collected at greater water depth from shallow sub-seabed strata has a provenance mainly in the northern part of East Greenland (68–73°N), which demonstrates the existence of a pre-Holocene EGC system initially extending to beyond the shelf edge.
Vincent Rinterknecht - One of the best experts on this subject based on the ideXlab platform.
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Cosmogenic 10Be dating of ice sheet marginal belts in Mecklenburg-Vorpommern, Western Pomerania (northeast Germany)
Quaternary Geochronology, 2014Co-Authors: Vincent Rinterknecht, Andreas Börner, Didier Bourlès, Régis BraucherAbstract:Abstract Northeastern Germany was repeatedly covered by the Scandinavian Ice Sheet during the last glaciation and a succession of distinct ice marginal belts is present in Mecklenburg-Vorpommern. We used surface exposure dating to develop a time frame for the retreat of the ice margin. Two samples from the Saalian ice marginal belt give Weichselian ages, a problem that has also been encountered further south when attempting to date the same ice marginal belt (the Hoher Flaming) in Brandenburg. One sample from the Frankfurt moraine is too young to be associated with this Glacial Feature. Another single sample from the Velgast extent gives also an exposure age that is too young to be associated with this Glacial Feature. These two examples highlight the necessity to sample multiple boulders on the same Feature to obtain a reliable exposure age. Fourteen samples were collected on the Pomeranian moraine and 12 were used to calculate an average deposition time of 15.6 ± 0.6 10 Be kyr. Two samples were removed from the age distribution based on statistical grounds. This result is in good agreement with results obtained in Brandenburg where the Pomeranian moraine was dated at 16.4 ± 0.7 10 Be kyr. Five samples from the Mecklenburgian moraine give an average age of 13.7 ± 0.6 10 Be kyr in good chronological order with the Pomeranian moraine age. One sample (MVP-21) from the Mecklenburgian moraine was corrected for burial effect based on historical documents demonstrating that if known, the recent past history of exposure of a surface can be appropriately used to calculate an exposure age. Together, this new data set highlights: 1. the difficulty to date surfaces older than the Weichselian glaciation when using only one cosmogenic radionuclide, 2. the consistency of the results obtained for the Pomeranian moraine across northeastern Germany using cosmogenic Be-10.
Christopher Juhlin - One of the best experts on this subject based on the ideXlab platform.
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the structure and stratigraphy of the sedimentary succession in the swedish sector of the baltic basin new insights from vintage 2d marine seismic data
Tectonophysics, 2016Co-Authors: Daniel Sopher, Mikael Erlstrom, Nicholas Bell, Christopher JuhlinAbstract:Abstract We present five interpreted regional seismic profiles, describing the full sedimentary sequence across the Swedish sector of the Baltic Sea. The data for the study are part of an extensive and largely unpublished 2D seismic dataset acquired between 1970 and 1990 by the Swedish Oil Prospecting Company (OPAB). The Baltic Basin is an intracratonic basin located in northern Europe. Most of the Swedish sector of the basin constitutes the NW flank of a broad synclinal depression, the Baltic Basin. In the SW of the Swedish sector lies the Hano Bay Basin, formed by subsidence associated with inversion of the Tornquist Zone during the Late Cretaceous. The geological history presented here is broadly consistent with previously published works. We observe an area between the Hano Bay and the Baltic Basin where the Palaeozoic strata has been affected by transpression and subsequent inversion, associated with the Tornquist Zone during the late Carboniferous–Early Permian and Late Cretaceous, respectively. We propose that the Christianso High was a structural low during the Late Jurassic, which was later inverted in the Late Cretaceous. We suggest that a fan shaped Feature in the seismic data, adjacent to the Christianso Fault within the Hano Bay Basin, represents rapidly deposited, coarse-grained sediments eroded from the inverted Christianso High during the Late Cretaceous. We identify a number of faults within the deeper part of the Baltic Basin, which we also interpret to be transpressional in nature, formed during the Caledonian Orogeny in the Late Silurian–Early Devonian. East of Gotland a number of sedimentary structures consisting of Silurian carbonate reefs and Ordovician carbonate mounds, as well as a large Quaternary Glacial Feature are observed. Finally, we use the seismic interpretation to infer the structural and stratigraphic history of the Baltic and Hano Bay basins within the Swedish sector.