Ancient pre-glacial erosion surfaces preserved beneath the West Antarctic Ice Sheet
Summary: We use ice-penetrating-radar data to identify a laterally continuous, gently sloping topographic block, comprising two surfaces separated by a distinct break in slope, preserved beneath the Institute and Möller ice streams, West Antarctica. We interpret these features as extensive erosion surfaces, showing that ancient (pre-glacial) surfaces can be preserved at low elevations beneath ice sheets. Different erosion regimes (e.g. fluvial and marine) may have formed these surfaces.
K. C. Rose, N. Ross, T. A. Jordan, R. G. Bingham, H. F. J. Corr, F. Ferraccioli, A. M. Le Brocq, D. M. Rippin, and M. J. Siegert Earth Surf. Dynam., 3, 139-152, 2015 AbstractFinal Revised Paper (PDF, 8312 KB)Discussion Paper (ESURFD)
16 Feb 2015
Macro-roughness model of bedrock–alluvial river morphodynamics
Summary: The saltation-abrasion model captures bedrock incision due stones striking bedrock. We present the Macro-Roughness-based Saltation-Abrasion-Alluviation (MRSAA) model, which tracks spatiotemporal variation of both bedload and alluvial thickness. It captures migrating waves of incision upstream and alluviation downstream. We apply it to incision problems not captured by saltation-abrasion, including the response to alluviation and stripping, and a simplified graben with uplift and subsidence.
A reduced-complexity model for river delta formation – Part 2: Assessment of the flow routing scheme
Summary: In this work we assess the flow-routing component (FlowRCM) of our delta formation model, DeltaRCM. We found that with the level of complexity reduction, FlowRCM is able to produce channel network-scale hydrodynamic details, which provide further insights into the connection between delta flow structures and the morphodynamic outcome.
A reduced-complexity model for river delta formation – Part 1: Modeling deltas with channel dynamics
Summary: In this work we present DeltaRCM, a reduced-complexity model for river delta formation. It is a rule-based cellular morphodynamic model, in contrast to reductionist models based on detailed computational fluid dynamics. DeltaRCM is able to resolve channel dynamics and to produce stratigraphy. We also explain the meaning of complexity reduction, especially the essential processes to be included in modeling deltas.
Re-evaluating luminescence burial doses and bleaching of fluvial deposits using Bayesian computational statistics
Summary: Rivers transport sediment from mountains to coast, but on the way sediment is trapped and re-eroded multiple times. We looked at Rhine river sediments to see if they preserve evidence of how geomorphic variables have changed over time. We found that measured signals potentially relate to water level and river management practices. These relationships can be treated as hypotheses to guide further research, and our statistical approach will increase the utility of research in this field.
Erosional response of an actively uplifting mountain belt to cyclic rainfall variations
Summary: We have derived a simple solution to the stream power law equation governing the erosion of rapidly uplifting tectonic areas assuming that rainfall varies as a periodic function of time. We show that the erosional response of this forcing is characterized by an amplification of the resulting erosional flux variations as well as a time lag. We show how this time lag can be important in interpreting several geological observations.
An overview of underwater sound generated by interparticle collisions and its application to the measurements of coarse sediment bedload transport
Summary: The paper deals with the measurement of coarse gravel transport in rivers and coastal environments. Quantifying this bedload is generally challenging. The approach adopted here is to use the acoustic sediment-generated noise, SGN, radiated from the interparticle collisions of the mobile bed material. A theoretical model of the radiated sound due to the collisions is presented, and the results are related to the application of SGN to the measurement of bedload transport and mobile particle size.
Dynamics and mechanics of bed-load tracer particles
Summary: This study tracked the episodic motion of coarse sediment cobbles over 2 years to unravel how floods in mountain rivers move sediment. Despite large fluctuations in river discharge and natural variability in climate and topography, observed sediment dynamics agree well with theory and small-scale laboratory experiments; results demonstrate that sediment particle motion can be predicted from a record of river flow depth, providing a direct link between climate and sediment transport.