Arkansas ; Biogenic process ; Fauna ; Mountain ; Regolith ; Soil ; Tree ; United States of America ; Weathering
The goal of this paper is to determine the processes and/or environmental controls responsible for the distribution of rock fragments in soils and weathering mantles in the Ouachita Mountains, and the implications for regolith evolution
. The regolith is a dynamic feature, reflecting the influences of vertical and horizontal processes, of active weathering at the bedrock interface, and of surficial sediment movements. The role of trees in redistributingrock fragments suggests that significant
regolith mixing occurs over time scales associated with forest vegetation communities.
Biomechanical effects of trees on soil and regolith : beyond treethrow
Arbre ; Arkansas ; Effet biomécanique ; Etats-Unis ; Modèle conceptuel ; Propriétés du sol ; Régolithe ; Sol ; Sol forestier ; Transport sédimentaire
Arkansas ; Conceptual model ; Forest soil ; Regolith ; Sediment transport ; Soil ; Soil properties ; Tree ; United States of America
The aim of this study was to investigate biomechanical effects of trees beyond treethrow, particularly displacement by tree growth and the potential for transport of regolith material into stump holes. Specifically, they sought to document
the extent of surface displacement (as indicated by rock fragments) and formation of stump rot depressions; to estimate the importance of these biomechanical effects relative to uprooting; and to identify common patterns of soil and regolith development
The enrichment of quartz in regolith, and the resulting bias in cosmogenic erosion rate estimates, can be quantified using concentrations of immobile elements (such as zirconium) in bedrock and regolith. Here the AA. show that the erosion rate bias
introduced by regolith dissolution is less than 12%, across 22 granitic catchments that span a wide range of temperate climates. Except in extreme weathering environments, biases due to regolith dissolution will be a small component of the overall uncertainty
Utilisation de l'analyse multivariée pour étudier les relations entre les formes de relief, les dimensions des particules du regolithe et les processus de géomorphogenèse dans le Bassin linthorpe, District Darling Downs, Queensland Sud-Est.
An experimental form of mapping has been tried, initially at 1 :5 000 000 scale covering the whole of Australia and then at 1 : 1 000 000 scale over the Kalgoorlie area of SE Western Australia. With appropriate interpretation the Kalgoorlie Regolith
Estimates of the rate of regolith production using 10Be and 26Al from an alpine hillslope
The production of regolith is a fundamental geomorphic process because most surface processes transport only unconsolidated material. The AA. use concentrations of the cosmogenic radionuclides (CRNs) 10Be and 26Al in regolith and bedrock to deduce
the rate of production of regolith on an alpine hillslope in the Wind River Range, Wyoming. These calculations are based on a theoretical model which is developed here. This model shows that it is important to consider dissolution of regolith in regolith
Comparative study ; Diabase ; Geochemistry ; Granite ; Micromorphology ; Porosity ; Regolith ; United States of America ; Virginia ; Weathering
Here, the AA. investigate what controls the depth of regolith formed on ridges of 2 rock compositions with similar initial porosities in Virginia (USA). A priori, they predicted that the regolith on diabase would be thicker than on granite because
oxidizing biotite at 20 m depth, and the lower iron (Fe) content in the felsic rock. Such porosity allows pervasive advection and deep oxidation in the granite. These observations may explain why regolith worldwide is thicker on felsic compared to mafic rock
under similar conditions. To understand regolith formation will require better understanding of such deep oxidation reactions and how they impact fluid flow during weathering.
Regolith residence time and the concept of surface age of the Piedmont peneplain in Appalachian geomorphology.
The A. presents a model for the continuous production and removal of Appalachian Piedmont upland regolith, and compares the mass flux (mass/area-time) from the Piedmont, determined from independent geochemical and geomorphic measurements
On the relationship between bedrock lowering and regolith thickness
Une équation générale est proposée pour la relation entre l'abaissement du niveau de la roche-mère et l'épaisseur des régolithes. Elle inclut comme cas d'espèce les hypothèses de Ahnert, Armstrong, Culling, Kirkby et Young, au moins approximées.
Regolith behaviour and physical weathering of clayey mudrock as dependent on seasonal weather conditions in a badland area at Vallcebre, Eastern Pyrenees
This work describes some properties of the regolith through the seasons, together with the known factors that control physical weathering (humidity and temperature oscillations), and some of the hydrological and erosive controls effected
Rill development and badland regolith properties in Rill erosion. Processes and significance.
The AA. consider the characteristics of rill systems developed on Eocene and Miocene marls at two sites in Granada Province, Spain, and on smectitic mudstones in western Canada. Rill system development is closely related to regolith hydrologic
properties and is viewed as being analogous to, and governed by, essentially the same properties as artificial field drains. Close similarities in regolith characteristics and response to rainfall in the two areas are noted.
Geophysical and remote sensing-based approach to model regolith thickness in a data-sparse environment
Géotechnique ; Modèle ; Modèle numérique de terrain ; Pakistan ; Pakistan du Nord ; Risque naturel ; Risque sismique ; Régolithe ; Régression linéaire ; SPOT ; Télédétection
Digital elevation model ; Geotechnics ; Linear regression ; Model ; Natural hazards ; Pakistan ; Regolith ; Remote sensing ; SPOT ; Seismic hazard
The AA. developed a generic remote sensing and geophysics based approach to model regolith thickness for areas with limited possibility of direct field observations. The approach was tested in a seismically-active and depositional landscape
in northern Pakistan. Regolith thickness was sampled at exposed bedrock outcrops along the river bed and scarps. At unexposed sites the regolith-bedrock interface was identified through electrical resistivity survey, thus providing an indirect measurement
of regolith thickness. A geomorphic classification of landforms and topographic attributes were derived from a remote sensing-based (ASTER) digital elevation model and SPOT-5 satellite imagery. A multivariate linear model based on landform, elevation
and distance to stream was able to predict the regolith thickness including field-observed abrupt changes at landform boundaries.
Regolith ; Soil ; Spatial analysis ; Spatial variation ; Statistical analysis ; Stratigraphy ; Texas ; United States of America ; Weathering
Complexity in weathering profiles may reflect variability in the parent material and/or complex feedback relationships within regolith weathering systems. Because regolith formation modifies or destroys the parent material, it is difficult
The Araguás experimental catchment has been monitored to study badland dynamics in the Central Pyrenees. Previous studies of weathering processes within the catchment reported strong regolith dynamics associated with seasonal variations
in the temperature and moisture regimes. A preliminary analysis of hydrological response and suspended sediment transport data recorded at a gauging station also demonstrated seasonal trends. The main objective of this study is to understand the effect of regolith
dynamics on sediment detachment and infiltration processes, based on field studies using simulated rainfall. The experiment design was based on seasonal differences in the physical conditions of surface regolith and the general trends of hydro
-sedimentological responses. Rainfall simulations were conducted on small plots using a pressure nozzle. Results and discussion. In conclusion, it is indicated that seasonal differences in detachment and infiltration depend on the nature of regolith development.
Regolith stripping and the control of shallow translational hillslope failure : application of a two-dimensional coupled soil hydrology-slope stability model, Hawke's Bay, New Zealand
Dynamique de versant ; Glissement de terrain ; Géotechnique ; Humidité du sol ; Hydrologie ; Modèle ; North Island ; Nouvelle-Zélande ; Précipitation ; Régolithe ; Seuil ; Versant
Geotechnics ; Hydrology ; Landslide ; Model ; New Zealand ; North Island ; Precipitation ; Regolith ; Slope ; Slope dynamics ; Soil moisture ; Threshold
This paper explores the hypothesised influence of progressive regolith stripping and redeposition on slope failure using a recently developed process-based model. This model couples dynamic hydrology with slope stability analysis, allowing to relax
Erosion rate ; Geochemistry ; Granite ; Mathematical model ; Model ; Regolith ; Weathering
where albite is completely depleted in the weathering zone. With an increase in erosion rate, transition and kinetic regimes are established. The steady-state thickness of regolith decreases with increasing erosion rate in the local equilibrium
and transition regimes, but in the kinetic regime, this thickness is independent of erosion rate. Analytical expressions derived from the model are used to show that regolith production rates decrease exponentially with regolith thickness. This model illustrates
Rock damage and regolith transport by frost : an example of climate modulation of the geomorphology of the critical zone
Changement climatique ; Colorado ; Dynamique de versant ; Etats-Unis ; Gelée ; Modèle ; Météorisation ; Porosité ; Propriétés du sol ; Périglaciaire ; Régolithe ; Température du sol ; Versant
Climatic change ; Colorado ; Frost ; Model ; Periglacial features ; Porosity ; Regolith ; Slope ; Slope dynamics ; Soil properties ; Soil temperature ; United States of America ; Weathering
comprise rock detachment into the mobile layer, mobile regolith transport, and a channel incision or aggradation boundary condition. They extend this system into the deep critical zone by considering a weathering damage zone below the mobile regolith
the example of rock damage by frost-generated crack growth. Finally the AA. link the frost cracking damage model, a mobile regolith production rule in which rock entrainment is conditioned by the damage state of the rock, and a frost creep transport model
Active layer ; England ; Freeze-thaw cycle ; Geochemistry ; Mesozoic ; Model ; Nottinghamshire ; Palaeo-environment ; Periglacial features ; Regolith ; Sandstone ; United Kingdom ; Weathering
This paper examines the weathering processes that have combined to produce the distribution of soil-regolith (SR) thickness across the Triassic Sherwood Sandstone Group outcrop in Nottinghamshire. Firstly, the AA. examine the long-term chemical
weathering processes in relation to the physical properties of the soil-regolith-saprolite. Then, they propose that the mechanism through which the clay cement was eased apart was through freeze–thaw processes associated with the summer active layer
starting conditions for input variables. These were combined with known data for thermal conductivity, bulk density and moisture content of the Sherwood Sandstone regolith. Model predictions of the distribution of SR thickness accurately reflect