ABSTRACT We present a new method that can be used to quantitatively evaluate the consistency betw... more ABSTRACT We present a new method that can be used to quantitatively evaluate the consistency between balanced section restorations and thermochronological datasets from orogenic belts. We have applied our method to a crustal-scale area-balanced cross-section restoration along a profile in the Central Pyrenees. This restoration is well constrained and supported by a wide variety of geological and geophysical data. Moreover, an extensive thermochronological dataset has been collected independently in the area. We use the structural-kinematic software 2D-Move™ to constrain a set of velocity fields that describes the kinematics of the Central Pyrenees. Using these velocity fields as input for the thermo-kinematic code PECUBE, we derive predictions of the thermal history and a range of thermochronometric ages for the modeled area. We find that the kinematic history of the belt as inferred from section balancing is in good agreement with the published thermochronological data. High-temperature (zircon fission-track and K-feldspar Ar-Ar) data constrain the thermal structure of the belt as well as the timing of underplating. Low-temperature (apatite fission-track and (U-Th)/He) data require late syn-orogenic sedimentary burial of the southern flank of the Pyrenees between Late-Eocene (40 Ma) to Late-Miocene (9 Ma) times, consistent with previous studies, and imply that no such burial occurred on the northern flank.
Many studies (e.g., von Blanckenburg, 2005; Wittmann et al., 2007) have shown that in-situ produc... more Many studies (e.g., von Blanckenburg, 2005; Wittmann et al., 2007) have shown that in-situ produced cosmogenic nuclide measurements of stream sediments provide a powerful tool to study erosion processes at catchment scales and lead to better constrain interactions between tectonics, climate and surface processes within mountain belts. This study aims to quantify erosion processes on post-glacial timescales in the Pelvoux-Ecrins
In mechanical studies of pumping a playground swing, two methods of energy insertion have been id... more In mechanical studies of pumping a playground swing, two methods of energy insertion have been identified: parametric pumping and driven oscillation. While parametric pumping involves the systematic raising and lowering of the swinger's center of mass (CM) along the swing's radial axis (rope), driven oscillation may be conceived as rotation of the CM around a pivot point at a fixed distance to the point of suspension. We examined the relative contributions of those two methods of energy insertion by inviting 18 participants to pump a swing from standstill and by measuring and analyzing the swing-swinger system (defined by eight markers) in the sagittal plane. Overall, driven oscillation was found to play a major role and parametric pumping a subordinate role, although the relative contribution of driven oscillation decreased as swinging amplitude increased, whereas that of parametric pumping increased slightly. Principal component analysis revealed that the coordination pattern of the swing-swinger system was largely determined (up to 95%) by the swing's motion, while correlation analysis revealed that (within the remaining 5% of variance) trunk and leg rotations were strongly coupled.
ABSTRACT We present a new method that can be used to quantitatively evaluate the consistency betw... more ABSTRACT We present a new method that can be used to quantitatively evaluate the consistency between balanced section restorations and thermochronological datasets from orogenic belts. We have applied our method to a crustal-scale area-balanced cross-section restoration along a profile in the Central Pyrenees. This restoration is well constrained and supported by a wide variety of geological and geophysical data. Moreover, an extensive thermochronological dataset has been collected independently in the area. We use the structural-kinematic software 2D-Move™ to constrain a set of velocity fields that describes the kinematics of the Central Pyrenees. Using these velocity fields as input for the thermo-kinematic code PECUBE, we derive predictions of the thermal history and a range of thermochronometric ages for the modeled area. We find that the kinematic history of the belt as inferred from section balancing is in good agreement with the published thermochronological data. High-temperature (zircon fission-track and K-feldspar Ar-Ar) data constrain the thermal structure of the belt as well as the timing of underplating. Low-temperature (apatite fission-track and (U-Th)/He) data require late syn-orogenic sedimentary burial of the southern flank of the Pyrenees between Late-Eocene (40 Ma) to Late-Miocene (9 Ma) times, consistent with previous studies, and imply that no such burial occurred on the northern flank.
Many studies (e.g., von Blanckenburg, 2005; Wittmann et al., 2007) have shown that in-situ produc... more Many studies (e.g., von Blanckenburg, 2005; Wittmann et al., 2007) have shown that in-situ produced cosmogenic nuclide measurements of stream sediments provide a powerful tool to study erosion processes at catchment scales and lead to better constrain interactions between tectonics, climate and surface processes within mountain belts. This study aims to quantify erosion processes on post-glacial timescales in the Pelvoux-Ecrins
In mechanical studies of pumping a playground swing, two methods of energy insertion have been id... more In mechanical studies of pumping a playground swing, two methods of energy insertion have been identified: parametric pumping and driven oscillation. While parametric pumping involves the systematic raising and lowering of the swinger's center of mass (CM) along the swing's radial axis (rope), driven oscillation may be conceived as rotation of the CM around a pivot point at a fixed distance to the point of suspension. We examined the relative contributions of those two methods of energy insertion by inviting 18 participants to pump a swing from standstill and by measuring and analyzing the swing-swinger system (defined by eight markers) in the sagittal plane. Overall, driven oscillation was found to play a major role and parametric pumping a subordinate role, although the relative contribution of driven oscillation decreased as swinging amplitude increased, whereas that of parametric pumping increased slightly. Principal component analysis revealed that the coordination pattern of the swing-swinger system was largely determined (up to 95%) by the swing's motion, while correlation analysis revealed that (within the remaining 5% of variance) trunk and leg rotations were strongly coupled.
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Papers by Peter Beek