With regard to its etchplain character, it is proposed by the A. that the development of the Baltic Shield relief can be ascribed to the chemical weathering that took place in Northern Europe during the Silurian-Carboniferous and the Jurassic
-Tertiary periods. The resulting weathering crust was probably removed during the Permian-Triassic (stripping) and Quaternary (glaciations). Neotectonic crust movements continuously modify the relief of the Baltic Shield.
Weathering and weathering residuals on the Canadian Shield
A study of the distribution and characteristics of saprolites on the southeast section of the Canadian Shield showed that a close relationship exists between bedrock lithology, site of the saprolite by respect to local iceflow direction, and its
the Phanerozoic. This has important applications for the evaluation of Phanerozoic crustal movements as well as implications for the assessment of glacial erosion. The approach is thought to be most valuable for comparative studies of shield geomorphology
in general and with the Laurentian Shield in particular.
Calculation of the cosmogenic nuclide production topographic shielding scaling factor for large areas using DEMs
surface process models (SPMs), necessitate a fast and accurate algorithm for the calculation of topographic shielding. This paper describes a method that uses relief shadow modelling to calculate the proportion of the incoming cosmic radiation
that is shielded by the surrounding topography for large areas using DEMs.
Quantifying the shapes of U.S. landfalling tropical cyclone rain shields
This study utilizes geographic information systems to spatially analyze radar returns and calculate several metrics that quantify the shapes of TC (Tropical Cyclone) rain shields. Three stepwise discriminant analyses are performed to determine which
of the shape metrics distinguish among TCs categorized by : intensity, distance, traveled inland, and orientation of terrain encountered. Results confirm that TC rain shields often assume noncircular shapes. Utilizing shape indices to model rain shields could
Plan-curvature effect on the formation of tumuli on shield volcanoes : an example from Leitin lava flow field in Iceland
On the Leitin shield volcano in SW Iceland the area distribution of tumuli is mainly controled by the plan curvature. A density increase in tumuli is associated with peaks in the plan convexity. This follows because high plan convexity forces
This study investigates the ability of the Shields relation to predict the initiation of sediment transport by overland flow on desert hillslopes. The Shields relation is evaluated using data collected from a series of overland flow experiments
on runoff plots in southern Arizona. Because the data deviate in a systematic manner from the Shields relation, alternative threshold relations are developed and discussed.
Scaling factors for the rates of production of cosmogenic nuclides for geometric shielding and attenuation at depth on sloped surfaces
Geophysics ; Isotope analysis ; Model ; Mountain ; Numerical model ; Shield ; Slope ; Slope gradient
The decrease in rates of production of cosmogenic nuclides occurs because of shielding of cosmic rays by mountains, sloped surfaces, and local rock formations that block them. When a large part of the sky is blocked, this correction is large
Effects of terrain smoothing on topographic shielding correction factors for cosmogenic nuclide-derived estimates of basin-averaged denudation rates
One important issue that has yet to be addressed is the effect of the accuracy and resolution of terrain representation by a digital elevation model (DEM) on topographic shielding correction factors. Topographic metrics scale with the resolution
of the elevation data, and terrain smoothing has a potentially large effect on the correction of terrestrial cosmogenic nuclide production rates for skyline shielding. For rough, high-relief landscapes, the effect of terrain smoothing can easily exceed analytical
errors, and should be taken into account. Here the AA. demonstrate the effect of terrain smoothing on topographic shielding correction factors for various topographic settings, and introduce an empirical model for the estimation of topographic shielding
The influence of roughness geometry and shields parameter on flow resistance in gravel-bed channels
friction factor parameter values and the ones calculated by the proposed semi-logarithmic relationship are explained by the ratio between the Shields parameter and its critical value. The analysis shows that estimates of the friction factor parameter
Sedimentary links and the spatial organization of Atlantic salmon (Salmo salar) spawning habitat in a Canadian Shield river
First, the AA. propose an extension of the sedimentary link concept for lower relief, old mountain landscapes and test its utility along the Ste Marguerite River (SMR), a salmon river draining the Canadian Shield in the Saguenay region of Québec
Supplementary data confirming the relationship between critical Shields stress, grain size and bed slope
for a range of flows at different bed slopes. A reference transport method was used to define the beginning of sediment motion. The experimental data confirm the recent finding that the critical Shields stress for motion of coarse uniform sediment varies
Lithological mapping and structural analysis of Proterozoic rocks in part of the Southern Arabian Shield using Landsat images in Special issue : Advances in geological remote sensing.