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Tunnel valley genesis

Tunnel valley genesis
Much controversy exists in literature concerning the processes by which tunnel valleys evolve, and a number of theories now exist in this regard. This article aims to evaluate critically the literature on tunnel valleys, focusing specifically
on the major theories which attempt to explain their formation. Before doing so, however, it summarizes salient aspects of tunnel valley geomorphology, and the sedimentology of their infills. Tunnel valleys incised into both bedrock and unconsolidated sediments
1996

Wind-tunnel modelling of the influence of vegetation structure on saltation threshold
This paper is concerned with the development of predictive relations for application to the natural or spontaneous vegetation cover of arid and semiarid lands. Wind-tunnel experiments using arrays of model roughness elements to simulate vegetation
1996

The role of streamline curvature in sand dune dynamics: evidence from field and wind tunnel measurements
Field measurements on an unvegetated, 10 m high barchan dune in Oman are compared with measurements over a 1:200 scale fixed model in a wind tunnel. This particularly concerns the determination of the pattern of shear stress on the windward slope
1996

Saltation and wind-flow interaction in a variable slope wind tunnel
This paper describes how the characteristics of the boundary layer have been tested in a long horizontal wind tunnel. Then the AA. present data from a series of measurements in the SWT where they have studied flow characteristics over saltation
1996

Radiocarbon dating by high-sensitivity liquid scintillation counting of wood from the Fox permafrost tunnel near Fairbanks, Alaska
1996

Published accounts of outburst floods from glacier-dammed lakes show that a significant number of such floods are associated not with drainage through a tunnel incised into the basal ice, the process generally assumed, but rather with ice-marginal
drainage, mechanical failure of part of the ice dam, or both. The AA. develop a simple physical model of the breach-widening process for non-tunnel floods. Calculations based on the model simulate quite well outbursts from Lake George, Alaska.
1996

Climate-controlled glacial erosion in the unconsolidated sediments of Northwestern Europe, based on a genetic model for tunnel valley formation
1996

This paper deals with the effect of rainfall on the process of wind erosion of beach sands and presents results from both field and wind tunnel experiments. The study was carried out using fine, well sorted beached sand of one particular beach
. The influence of the surface moisture content on the initiation of wind erosion and on the vertical distribution of transported sand particles was studied in a wind tunnel. Moisture significantly increased threshold wind velocities for the initiation of sediment
1996

This paper reports on a laboratory wind tunnel based comparison of the stability of mono-specific crusts formed by each of 3 selected photoautotrophs: Chlamydomonas acidophila, Lyngbya sp., and Nostoc commune. Only filamentous cyanobacteria
1996

The vertical distribution of the wind-blown sand flux in a 40 cm low layer above the ground surface was investigated through laboratory wind-tunnel tests and field measurements on the mobile dune surface during sand storms in the Taklamakan Desert
1996

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