DEGRADATION OF ONE-HUNDRED-METER-SCALE ROCKY EJECTA CRATERS AT THE INSIGHT LANDING SITE ON MARS AND IMPLICATIONS FOR SURFACE PROCESSES AND EROSION RATES

2018 ◽  
Author(s):  
Nicholas H. Warner ◽  
◽  
Julianne Sweeney ◽  
Vamsi Ganti ◽  
Matthew P. Golombek ◽  
...  
2021 ◽  
Author(s):  
Riccardo Reitano ◽  
Claudio Faccenna ◽  
Francesca Funiciello ◽  
Fabio Corbi ◽  
Pietro Sternai ◽  
...  

<p>In convergent systems, tectonics, erosion, and sedimentation control orogenic evolution. The nature of the interaction between these factors is still to be unraveled, because of their complex feedback that goes through different time and spatial scales. Here, we try to bind tectonics, erosion, and sedimentation by running laboratory-scale coupled analog models of landscape evolution, in which both tectonic forcing and surface processes are modeled, trying to unravel the nature of these multiple-interrelated processes. The analog apparatus consists of a rectangular box filled with a water-saturated granular material. The deformation is imposed by the movement of a rigid piston (backstop), while surface processes are triggered by simulated rainfall and runoff. We systematically vary the convergence velocity and the rainfall rate, testing how different boundary conditions affect the balance between tectonics and surface processes and the onset of steady-state configurations. We measure the competition between input fluxes (tectonics) and output fluxes (erosion) of material. The results show how analog models never achieve a steady-state configuration in which tectonic rates are perfectly balanced by erosion rates. Tectonics add more material to the accretionary wedge than is removed by erosion (about 2-5 times more). Still, erosional fluxes seem to reach an equilibrium with the applied tectonic flux. The foreland is always overfilled with sediments, and we argued how the storage of sediments in front of a wedge can strongly divert the orogenic system from the “classical” steady state configuration. This work analyzes which are the main differences between analog and theoretical models and if/how the results coming from analog models can be exportable when interpreting natural landscape morphologies and force balance.</p>


1999 ◽  
Vol 28 ◽  
pp. 282-290 ◽  
Author(s):  
Jean Braun ◽  
Dan Zwartz ◽  
Jonathan H. Tomkin

AbstractWe have developed a new surface-processes model incorporating large-scale fluvial processes, local hill-slope processes and glacial erosion. Ice thickness and velocity are calculated under a shallow-ice approximation. Simulation experiments in fast-growing orogens comparing the efficiencies of fluvial and glacial erosion, where the two are operating simultaneously over several glacial cycles, show that: glacial landscapes can support greater ice masses than fluvial landscapes; glacial valley and lake shapes create a disequilibrium between landform and land-forming process that leads to pulses of high erosion at the end of glacial periods; glacial erosion rates can reach a constant value in a uniformly growing orogen; and glacial erosion is capable of eroding drainage divides when the ice is moderately thick.


Geomorphology ◽  
2015 ◽  
Vol 228 ◽  
pp. 409-420 ◽  
Author(s):  
Lisa M. Tranel ◽  
James A. Spotila ◽  
Steven A. Binnie ◽  
Stewart P.H.T. Freeman

Science ◽  
2020 ◽  
Vol 367 (6484) ◽  
pp. 1358-1361 ◽  
Author(s):  
J. Starke ◽  
T. A. Ehlers ◽  
M. Schaller

Vegetation influences erosion by stabilizing hillslopes and accelerating weathering, thereby providing a link between the biosphere and Earth’s surface. Previous studies investigating vegetation effects on erosion have proved challenging owing to poorly understood interactions between vegetation and other factors, such as precipitation and surface processes. We address these complexities along 3500 kilometers of the extreme climate and vegetation gradient of the Andean Western Cordillera (6°S to 36°S latitude) using 86 cosmogenic radionuclide–derived, millennial time scale erosion rates and multivariate statistics. We identify a bidirectional response to vegetation’s influence on erosion whereby correlations between vegetation cover and erosion range from negative (dry, sparsely vegetated settings) to positive (wetter, more vegetated settings). These observations result from competing interactions between precipitation and vegetation on erosion in each setting.


2020 ◽  
Author(s):  
Lorenz Michel ◽  
Ritske S. Huismans ◽  
Sebastian G. Wolf

<p>Disentangling the interactions and possible feedbacks between tectonic and earth surface processes has been a focus of geoscientific research for the past decades. Recent work has highlighted the importance of erosional processes at the Earth’s surface for impacting e.g. the evolution of topography, deformation or the sedimentary yield. Many of these studies were conducted in convergent settings and fewer studies focused on extensional settings. Here, we present the results from forward numerical models, using a geodynamic model (Fantom) coupled with a landscape evolution model (Fastscape) in order to explore the coupling and interactions between tectonics and earth surface processes in extensional continental rift settings.</p><p>We model the formation of continental extensional rift systems and compare, how the structure of the subsequent rifts, topography and sedimentary yield evolve over time depending on the combination of five key parameters. For this, we run and compare a series of model experiments, varying crustal rheology (weak to strong crust), duration of extension (5 – 20 Myr), distribution of inherited strain (single vs. distributed weakness), efficiency of erosion (through different rock erodibilities) and the base level for erosion. The modeling results show that structure and topography of the intra-continental rift strongly depend on crustal strength, on the distribution of inherited strain and on the duration of extension. Formation of a major rift basin followed by considerable uplift of the rift shoulders and generation of topography is facilitated by models with a strong crust. The distribution of inherited strain controls the distribution of deformation, such that models with a distributed area of inherited strain yield wider rift zones with partly several, smaller basins. Additional to the respective base level of erosion, the build-up of topography plays a key role in driving the efficiency of erosion, such that high erosion rates are observed for models with significant topography. Hence, models that produce high topography (i.e. models with high crustal strength) display a significant sediment flux during the syn-rift phase. Furthermore, the activity of single faults is impacted by sediment loading, resulting in different styles of deformation, depending on the amount of delivered sediment. For all simulations, topography is erased rapidly (i.e. <5 Myr) following the cessation of rifting activity and rock uplift, if the erosional efficiency is high.</p><p>Taken together, our results suggest a strong dependency of the formation of topography, sediment flux and erosion on the respective tectonic circumstances. However, given that surface processes are efficient, the style of rifting can be impacted. Hence, our simulations suggest significant feedbacks between tectonic and surface processes.</p>


2000 ◽  
Vol 179 ◽  
pp. 155-160
Author(s):  
M. H. Gokhale

AbstractData on sunspot groups have been quite useful for obtaining clues to several processes on global and local scales within the sun which lead to emergence of toroidal magnetic flux above the sun’s surface. I present here a report on such studies carried out at Indian Institute of Astrophysics during the last decade or so.


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