Description: Establishing a sediment budget in the newly created “Kleine Noordwaard” wetland area in the Rhine–Meuse delta Eveline Christien van der Deijl, Marcel van der Perk, and Hans Middelkoop Earth Surf. Dynam., 6, 187-201, https://doi.org/10.5194/esurf-6-187-2018, 2018 To study the effectiveness of river delta restoration, we used field observations and elevation data to quantify the magnitude and spatial patterns of aggradation and erosion in a restored wetland in the Rhine-Meuse delta. Erosion and aggradation rates decrease over time, but aggradation compensates for sea-level rise and soil subsidence. Channels in the centre had aggraded, whereas the inlet and outlet eroded. Furthermore, sediment is in general uniformly distributed over the intertidal area.

Description: Tectonic controls of Holocene erosion in a glaciated orogen Byron A. Adams and Todd A. Ehlers Earth Surf. Dynam. Discuss., https//doi.org/10.5194/esurf-2018-9,2018 Manuscript under review for ESurf (discussion: open, 0 comments) Recent work has highlighted a strong, worldwide, glacial impact of orogen erosion rates over the last 2 Ma. While it may be assumed that glaciers increased erosion rates when active, the degree to which past glaciations influence Holocene erosion rates through the adjustment of topography is not known. In this study, we investigate the influence of long-term tectonic and post-glacial topographic controls on erosion in a glaciated orogen, the Olympic Mountains, USA. We present 14 new 10 Be and 26 Al analyses which constrain Holocene erosion rates across the Olympic Mountains. Basin-averaged erosion rates scale with basin-averaged values of 5-km local relief, channel steepness, and hillslope angle throughout the range, similar to observations from non-glaciated orogens. These erosion rates are not related to mean annual precipitation or the marked change in Pleistocene alpine glacier size across the range, implying that glacier modification of topography and modern precipitation parameters do not exert strong controls on these rates. Rather, we find that despite intense spatial variations in glacial modification of topography, patterns of recent erosion are similar to those from estimates of long-term tectonic rock uplift. This is consistent with a tectonic model where erosion and rock uplift patterns are controlled by the deformation of the Cascadia subduction zone.

Description: Effect of changing vegetation on denudation (part 2): Landscape response to transient climate and vegetation cover Manuel Schmid, Todd A. Ehlers, Christian Werner, Thomas Hickler, and Juan-Pablo Fuentes-Espoz Earth Surf. Dynam. Discuss., https//doi.org/10.5194/esurf-2018-13,2018 Manuscript under review for ESurf (discussion: open, 1 comment) We present a numerial modelling investigation into the interactions between transient climate and vegetation cover with hillslope and fluvial processes. We use a state-of-art landscape evolution model library (Landlab) and designed model experiments to investigate the effect of climate change and associated changes in surface vegetation cover on main basin metrics. This paper is a companion paper to Part 1 (this journal) which investigates the effect of climate change to surface vegetation cover.

Description: A lattice grain model of hillslope evolution Gregory E. Tucker, Scott W. McCoy, and Daniel E. J. Hobley Earth Surf. Dynam. Discuss., https//doi.org/10.5194/esurf-2018-4,2018 Manuscript under review for ESurf (discussion: open, 0 comments) This article presents a new technique for computer simulation of slope forms. The method provides a way to study how events that disturb soil or turn rock into soil add up over time to produce landforms. The model represents a cross section of a hypothetical landform is represented as a lattice of cells, each of which may represent air, soil, or rock. Despite its simplicity, the model does a good job of simulating a range of common of natural slope forms.

Description: Glacial Isostatic Adjustment modelling: historical perspectives, recent advances, and future directions Pippa L. Whitehouse Earth Surf. Dynam. Discuss., https//doi.org/10.5194/esurf-2018-6,2018 Manuscript under review for ESurf (discussion: open, 2 comments) This article is a contribution to a special issue on “Two centuries of modelling across scales”. It describes the historical observations, evolving hypotheses, and early calculations that led to the development of the field known as Glacial Isostatic Adjustment (GIA) modelling, which seeks to understand feedbacks between ice-sheet change, sea-level change, and solid Earth deformation. Recent advances are discussed. Future research in the field is likely to involve an interdisciplinary approach.

Description: Tracking the 26 Al/ 10 Be source-area signal in sediment-routing systems of arid central Australia Martin Struck, John D. Jansen, Toshiyuki Fujioka, Alexandru T. Codilean, David Fink, Réka-Hajnalka Fülöp, Klaus M. Wilcken, David M. Price, Steven Kotevski, L. Keith Fifield, and John Chappell Earth Surf. Dynam. Discuss., https//doi.org/10.5194/esurf-2017-76,2018 Manuscript under review for ESurf (discussion: final response, 3 comments) Measurements of cosmogenic nuclides 10 Be and 26 Al in sediment along central Australian streams show that lithologically-controlled magnitudes of source-area erosion rates (0.2–11 m/m.y.) are preserved downstream despite sediment mixing. Conversely, downstream-increasing sediment burial signals (〉 400 k.y.) indicate sediment incorporation from adjacent, long-exposed storages, which, combined with low sediment supply and discontinuous flux, likely favours source-area 10 Be- 26 Al signal masking.

Description: Temporal variability in detrital 10 Be concentrations in large Himalayan catchments Elizabeth H. Dingle, Hugh D. Sinclair, Mikael Attal, Ángel Rodés, and Vimal Singh Earth Surf. Dynam. Discuss., https//doi.org/10.5194/esurf-2017-73,2018 Manuscript under review for ESurf (discussion: open, 3 comments) Accurately quantifying sediment fluxes in large rivers draining tectonically active landscapes is complicated by the stochastic nature of sediment inputs. Cosmogenic 10 Be concentrations measured in modern river sands have been used to estimate 10 2 –10 4 year sediment fluxes in these types of catchments, where upstream drainage areas are often in excess of 10,000 km 2 . It is commonly assumed that within large catchments, the effects of stochastic sediment inputs are buffered such that 10 Be concentrations at the catchment outlet are relatively stable in time. We present eighteen new 10 Be concentrations of modern river and dated Holocene terrace and floodplain deposits from the Ganga River near to the Himalayan mountain front. We demonstrate that 10 Be concentrations measured in modern Ganga River sediments display a notable degree of variability, with concentrations ranging between ~ 9,000–19,000 atoms g −1 . We propose that this observed variability is driven by two factors. Firstly, by the nature of stochastic inputs of sediment (e.g. the dominant erosional process, surface production rates, depth of landsliding, degree of mixing) and, secondly, by the evacuation timescale of individual sediment deposits which buffer their impact on catchment-averaged concentrations. Despite intensification of the Indian Summer Monsoon and subsequent doubling of sediment delivery to the Bay of Bengal at ~ 11–7 ka, we also find that Holocene sediment 10 Be concentrations documented at the Ganga outlet have remained within the error of modern river concentrations. We demonstrate that in these systems, sediment flux cannot be simply approximated by converting detrital concentration into mean erosion rates and multiplying by catchment area as it is possible to generate considerably larger volumetric sediment fluxes whilst maintaining comparable average 10 Be concentrations.

Description: U–Th and 10 Be constraints on sediment recycling in proglacial settings, Lago Buenos Aires, Patagonia Antoine Cogez, Frédéric Herman, Éric Pelt, Thierry Reuschlé, Gilles Morvan, Christopher M. Darvill, Kevin P. Norton, Marcus Christl, Lena Märki, and François Chabaux Earth Surf. Dynam., 6, 121-140, https://doi.org/10.5194/esurf-6-121-2018, 2018 Sediments produced by glaciers are transported by rivers and wind toward the ocean. During their journey, these sediments are weathered, and we know that this has an impact on climate. One key factor is time, but the duration of this journey is largely unknown. We were able to measure the average time that sediment spends only in the glacial area. This time is 100–200 kyr, which is long and allows a lot of processes to act on sediments during their journey.

Description: Topographical change caused by moderate and small floods in a gravel bed ephemeral river – a depth-averaged morphodynamic simulation approach Eliisa S. Lotsari, Mikel Calle, Gerardo Benito, Antero Kukko, Harri Kaartinen, Juha Hyyppä, Hannu Hyyppä, and Petteri Alho Earth Surf. Dynam., 6, 163-185, https://doi.org/10.5194/esurf-6-163-2018, 2018 This paper analyses the timing of topographical changes of a gravel bed ephemeral river channel during consecutive and moderate- and low-magnitude floods by applying a morphodynamic model calibrated with pre- and post-event surveys using RTK-GPS and mobile laser scanning. The channel acted as a braided river during lower flows but as a meandering river during higher flows. The channel changes can be greater during the long-lasting receding phase than during the rising phase of the floods.

Description: Clay mineralogy, strontium and neodymium isotope ratios in the sediments of two High Arctic catchments (Svalbard) Ruth S. Hindshaw, Nicholas J. Tosca, Alexander M. Piotrowski, and Edward T. Tipper Earth Surf. Dynam., 6, 141-161, https://doi.org/10.5194/esurf-6-141-2018, 2018 For many applications in Earth sciences it is important to know where river and ocean sediments have originated. In this study we used geochemical and mineralogical tracers to characterise sediments from Svalbard. We find that the sediments are formed from two sources: old rocks in Greenland and younger rocks in Siberia. Glaciation influences how much of each end-member is present in the river sediments today, implying that the sediment composition can change through time as the climate changes.