Appendix Alphabetical List of Definitions and Descriptions of Terms Used in the Present Paper

Appendix Alphabetical list of definitions and descriptions of terms used in the present paper.

Alluvial fan: Fan-shaped accumulation mainly of gravelly to cobbly sediment, with slope dip decreasing from an apical maximum of about 15° to a few degrees to subhorizontal at distal end. Dominated by ephemeral surface runoff and/or by debris flows.

Apex (latin: peak): The uppermost part of a talus slope or of an alluvial fan.

Aqueous flow: Flow of a fluid, herein water, that per definition has zero shear strength (Newtonian fluid). In an aqueous flow with more than about 9% suspended cohesionless grains, depending on grain size distribution, grain collisions start to impart shear strength to the flow (Fisher 1971, p 916). Such heavily sediment-laden suspension are 'hyperconcentrated flows' that persist only over short intervals of time, and that typically show debris-flow behaviour during deposition (Collinson and Thompson 1989).

Carbonate mud: Herein used for mini-micritic to siltitic carbonate sediment of calcium-carbonatic to dolomitic mineralogy. In talus, a significant porportion of carbonate mud is of clastic origin.

Cirque, glacial cirque (German: Kar): Subcircular depression that is or was occupied by a cirque glacier ('Kargletscher').

Clast axes: a-axis = longest diameter; b-axis = intermediate diameter; c-axis = shortest diameter (Collinson and Thompson 1989). See also 'Clast fabrics' below.

Clast fabrics: t = transversal; p = parallel; i = imbricated. Example: a(p,t)/b(p,i) is downstream imbrication as formed by bedload transport in fluid flows (Collinson and Thompson 1989).

Clast-matrix relationship (see Francou 1990, p 250): openwork = devoid of primary matrix; clast-supported = clast support and pore space filled by matrix.

Conglobreccia: Corresponds to the term 'breccio-conglomerate' of Kearey (2001). Herein understood as a ruditic deposit composed of subequal amounts of both angular to subangular and subrounded to well-rounded clasts.

Debris flow: Flow of a fluid with critical shear strength (Bingham fluid, non-Newtonian fluid). On talus slopes, debris flows can be composed of (a) cohesionless clasts plus air (grain flows per original definition; Lowe 1976, p 188), (b) cohesionless clasts plus water (herein, these also are designated as grain flows), (c) of cohesionless clasts and up to more than 10% of fine-grained, more-or-less cohesive matrix (cohesive debris flows; e. g. Van Steijn 1988), (d) mixtures of matrix and/or clasts with snow or slush, and (e) frost-coated clasts plus air or snow (Hétu and Gray 2000). In the present context, pebbly mudflows and pure mudflows are insignificant.

Degradation (cliff degradation): Geomorphological term for lowering of a landscape feature by linear erosion and/or denudation.

Glacial chute (German: Gletschergasse): Deeply incised, trough-shaped, commonly dry valley flanked by cliffs that was incised by glacial erosion.

Plunge step: Vertical step a few decimeters to more than a metre in height in a bed of a bouldery to gravelly creek. Plunge steps are formed by arrays of boulders to cobbles, and give rise to a very short waterfall (see Montgomery and Buffington 1997).

Riffle: Plane to gently convex-upward stream bed of gravels (commonly with downstream-imbricated clasts) down stream of plunge steps (see Montgomery and Buffington 1997).

Rock cliff: Rocky slope steeper than 45° (Clowes and Comfort 1987, p 41).

Scale subdivision of form and size range (Summerfield, 1991, Table 1.1) as pertinent for present paper (our designation indicated in parentheses): 8th order: 1 km2 to 10 km2 ('macro-scale'). 9th order: 1 m2 to 1 km2 ('meso- scale'). 1oth order: 1 mm2 to 1 m2 ('micro-scale'). The designation in parentheses are ours, for sake of brevity in the present paper.

Slope steepness: > 45°: cliff; 30-45°: very steep; 18-30°: steep; 10-18°: moderately steep; 5-10°: moderate; 2-5°: gentle; < 2°: flat (Clowes and Comfort 1987, p 41) Talus cone: Cone-shaped accumulation mainly of gravelly to cobbly sediment, with slope dip decreasing from apical maximum of up to about 35° to a few degrees at distal end. Lower termination of talus cones commonly over a lateral distance of a few meters to a few tens of meters. Dominated by debris flows, ephemeral surface runoff, rockfall, snow avalanches.

References

Clowes A, Comfort P (1987) Process and Landform: An outline of contemporary geomorphology. Oliver and Boyd, Edinburgh, 335 pp

Collinson JD, Thompson DB (1989) Sedimentary Structures. Unwin Hyman, London, 207 pp

Fisher RV (1971) Features of coarse-grained, high-concentration fluids and their deposits. J Sed Pet 41:916-927

Francou B (1990) Stratification mechanisms in slope deposits in high subequatorial mountains. Permafr Perigl Proc 1:249-263

Hétu B, Gray JT (2000) Effects of environmental change on scree slope development throughout the postglacial period in the Chic-Choc Mountains in the northern Gaspé Peninsula, Québec. Geomorphology 32:335-355

Kearey P (2001) The New Penguin Dictionary of Geology. Penguin Group, London, 327 pp

Lowe DR (1976) Grain flow and grain flow deposits. J Sed Pet 46:188-199

Montgomery DR, Buffington JM (1997) Channel-reach morphology in mountain drainage basins. Geol Soc Amer Bull 109:596-611

Summerfield MA (1991) Global Geomorphology. Longman Scientific and Technical, Essex, 537 pp

Van Steijn H (1988) Debris flows involved in the development of Pleistocene stratified slope deposits. Z Geomorph N F Suppl 71:45-58