The Present Research Undertaking

thermal or moisture conditions the rocks under experimentation ever experience(d) in Nature. Key issues in this are such factors as the amount of water, the chemistry of the water, the rock temperatures and, particularly, the rate of change of temperature (boT/t), and the thermal gradient. Without such data, it cannot be known whether the laboratory experiments replicate the field situation or not.

Thus, "Field corroboration is something of a misplaced concept with respect to

frost weathering. At present there is no adequate criterion to establish that

bedrock weathering or further comminution of rock fragments has been dominated

by freeze-thaw weathering. Nevertheless, it is clear that the majority of periglacial

researchers believe that freeze-thaw weathering of bedrock is an established fact,

and that it is an acceptable premise upon which to base many secondary concepts

(e.g. cryoplanation)" (Thorn, 1992, p. 11). The problems cited above with regard

to laboratory experiments (Le. the need for data on rock temperatures, moisture

content, etc.) apply equally to the use of the freeze-thaw concept in the generation

of landforms. Rather than deduction based on empirical data, it is usually the

observation of 'angular clasts' that provides the assumption of 'freeze-thaw'

weathering as factor in landform origin. Thus, the invocation of freeze-thaw as a

central tenet of nivation, cryoplanation, blockfields, tors, etc. is without empirical

foundation (Thorn, 1988, 1992).

as a result of its wide spectrum of "cold climates". It was necessary to consider all aspects of weathering (although mechanical processes were the major consideration) otherwise the predominance of processes other than freeze-thaw might not be recognised nor the potential synergistic relationships or the temporal/spatial variability in process identified. While this study deals almost exclusively with the mechanical processes, it is recognised that chemical processes must also play a role. Logistics and expertise did not allow equal consideration of the chemical weathering component.

Those factors that were monitored, as a foundation for understanding the nature

and timing of the weathering, included rock temperature, rock moisture content and

chemistry, rock properties and the study of various landforms and sediments

associated with cold environments (past and present). Rock temperature was

monitored both at the rock surface and at various depths, and the rate of change

of temperature (/1T/t) and the thermal gradient were measured. Air temperature,

as well as potentially pertinent climatic factors that might influence rock

temperatures, such as radiation and wind, were monitored where possible. Spatial

and temporal variability of the above attributes were also investigated as key

factors whenever possible (Le. a variety of sites were monitored at different

frequencies and for varying lengths of time in order to determine spatial and

temporal variability of process). Moisture data included estimation of rock

moisture levels and gradients (and their variability through time, as well as

spatially), rock moisture chemistry, and ancillary studies of the geochemistry of

moisture sources. Rock properties included, where possible, tensile strength

(determined from point load compressive strength tests via existent correlation

equations), micro-indenter strength tests, permeability, porosity saturation

coefficient, absorption coefficient, p-wave ultrasonic velocity values, and

porosimetry. In some instances it was also possible to actually measure, or obtain

an indirect measurement of, weathering rates in the field.

Together, the above data provide the field and laboratory background against which determinations regarding weathering processes and rates could be attempted. These data could then be used to facilitate meaningful laboratory experimentation to investigate the processes and rates of weathering (Fig. 3).

Laboratory results could then be, in some instances, compared to field results to further refine both the laboratory experimentation and the overall assessment of weathering process(es) and rate(s). This was seen as an extremely important component of the study for, prior to this, few (if any) laboratory experiments were based on measured field parameters. This meant that the results could be applied back to the field with some degree of certainty that they were meaningful for that situation. Other laboratory experiments were undertaken to try and filter out the specific components of weathering - Le. where one process impacts on another (e.g. the role of wet/dry weathering within freeze-thaw weathering).

The above approach enabled the monitoring and measurement of field conditions considered to be those fundamental to the understanding of weathering.

Complementary laboratory experimentation, based on the field data, provided

additional information. Field studies also included investigation of landforms and

sediments where weathering, particularly freeze-thaw weathering, were argued to

be the major, if not the sole, factor in their development. With respect to

landforms, and to a lesser extent weathering, consideration was also given to the

role of animals/organisms. Although somewhat peripheral to the main theme of

this research, weathering due to algae was found to be a major factor at one

locality whilst at a number of sites animals (penguins, elephant seals, albatrosses,

musk ox, pika, marmots, yak, goats, and grizzly bears) were seen to play a

significant role in the development of some cold region landforms. As animals had

been rarely considered in this regard and may play a greater role than hitherto

thought, the findings are included as part of the overall picture of cold region

landform development. The work presented here provides an integrated look at

the complexity of cold region weathering processes and the development of

landforms and sediments in such regions.