Abstract
Three-dimensional fabric analysis was done in order to characterize the fabric of slope deposits gathered from various sources. Although the distribution of periglacial slope deposits on a logarithmic ratio plot partly overlaps those of nonperiglacial deposits such as soil creep, sediment flow plots, debris flow plots, talus, outwash and stratified slopes (in openwork beds) indicate low values of both C and K compared with those of periglacial slope deposits (Fig. 1, Table 1). This result leads to the conclusion that (1) the periglacial slope deposits have higher C and K values than non-periglacial deposits except for glacial ones; (2) the periglacial slope deposits are plotted in a zone with C ranging over 2.5, K ranging over 0.5 on the logarithmic ratio plot; and (3) it is, therefore, possible to distinguish the periglacial slope deposits from the non-periglacial ones by means of logarithmic ratio plots.
Three-dimensional fabric analysis of 2, 350 clasts in the site located on the fossil periglacial slope deposits in the Hidaka Mountains has been done to evaluate the relations of macro fabrics to both length of a-axis (Table 2) and clast shape (Table 3). The main results are that (1) clasts with a longer a-axis have macro fabrics with little deviation from mean orientation (Figs. 2 and 3); and (2) clast shape has little effect on fabric in the longer a-axis range (Fig. 4, Table 4).
Taking these results into consideration, azimuths and dips of clasts with longer a-axis have to be measured in order to gain fabrics with little deviation from mean orientation in periglacial slope deposits.
