Statistical Analysis of Directional Features - Geomathematics: Theoretical Foundations, Applications and Future Developments - page 279

Fig. 8.3 Reconstruction of approximate preferred paleocurrent direction and shape of paleodelta
from preferred current directions, Member C, Bjorne Formation, Melville Island (After Agterberg
et al. 1967 ). (a) Preferred directions of paleocurrent indicators at measurement stations; 0-isopach
applies to lower part of Member C only. (b) Graphical representation of solution of differential
equation for paleocurrent trends. Inferred approximate direction of paleoriver near its mouth is
N54.4 E (Source: Agterberg 1974 , Fig. 13)
All flow lines in Fig. 8.4a converge to a single line-shaped source. They have the
same asymptote in common which suggests the location of a river. An independent
method for locating the source of the sand consists of mapping the grade of the
largest clasts contained in the sandstone at a given place. Four grades of larges
clasts could be mapped in the area of study. They are: (1) pebbles, granule, coarse
sand; (2) cobbles, pebbles; (3) boulders, cobbles; and (4) boulders (max. 60 cm).
The size of the clasts is larger where the velocity of the currents was higher.
Approximate grade contours for classes 1-4 are shown in Fig. 8.4c for comparison.
This pattern corresponds to the contours constructed for the delta.