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and longitudal profiles of Yukon Territory. 
General resolution of Landsat images, approximately 80 m 
is delusive as the criterium for limitation of the size of 
detectable landforms.Third generation of Landsat data (prints 
or diapositives) have reduced resolution due to the repro- 
duction. Also local, variable, physiographical conditions 
influence the range of detectable landforms, which could 
vary from few hundred meters to kilometers. As examples of 
well detectable landforms could be listed medial, marginal and 
frontal morains in St.Elias Mtns. ,pattern of braided river 
channels in large proglacial valleys, alluvial fans,deltas 
and laguns in Arctic coastal zone, aufeís phenomena at the 
bottom of Arctic valleys and intermontagne depressions, man 
induced landforms related to the mineral exploration and 
road construction. The largest, well detectable forms 
belong to structural relief: mountain ridges, structuraly 
controled valleys, escarpments. 
Landforms which interpretability is subdued, due to the 
scarcity of indicators, are characterised by flatness , 
lack of lineaments or diseection, conformity of vegetation. 
To this group belong surfaces of denudaton, pediments, large 
river terraces, plains with fluvial ,lacustrine, fluvioglacial 
or thick frost rubble cover. Indicators of these forms are 
located more frequently in the merginal zones, but the transi- 
tional character of many forms must be also taken under 
consideration. 
Variable, physiographical conditions of Yukon Territory 
were always analysed together with morphological interpretation 
of images. The knowledge of these variances was based on 
the study of references and reconessance field work in 
different part of Yukon. 
Example of Landsat Mosaic interpretation; Nortwest part of 
Yukon Territory. 
Photo No.1 shows fragment of Landsat mosaic in scale 
1:1,000,000covering northwest part of Yukon Territory and 
adjacent fragment of Northwest Territgry. Geographical 
coordinates are 68-70?« N and 135-1414 W. 
The area is located in arcticand subarctic zones with 
continuous permafrost (Brown,1967). According to geological 
regionalisation of Canada into provinces and their subdivisions, 
(Douglas, 1973), the area lies in the contact zone between 
Arctic Continental Shelf, represented in the subaerial zone 
by Arctic Coastal Plain and Mackenzie Delta, Cordillera Orogen, 
represented by Northern Yukon Fold Complex. 
Bostock, in his Physiographical Regionalisation (Bostock, 
1948,1967) identified Arctic Coastal Plain with divisions;Yukon 
Coastal Plain and Mackenzie Delta, Cordillera Region with 
divisions; British Mtns.,Old Crow Range,Porcupine Plateau, 
Old Crow Plain and Richardson Mtns. Bostock(1948) described 
also smaller physiographical units but without their precise 
delineation and cartographical representation. 
More detailed geological investigations in this part of 
Canada have been carried out systematjcally from 1955, 
(Operation Porcupine of Canadian Geologic Survey).