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3.2 - CMDIAGRAM OF THE UNIT 2 AND MORPHODYNAMIC
IMPLICATIONS (fig. 3)
To obtain an understanding of the transport processes
associated with the deposition of the sandy and silty
members, particularly those in Unit 2, grain size
properties of samples from the main silty and sandy
beds were analysed on a Passega CM diagram (Passega,
1957, 1964, 1977; Passega & Byramjee, 1969).
Following particle size analysis, the C (coarsest 1
percentile in microns) and the M (median size in
microns) values were plotted on a log: log graph. The
plots suggest three groups in a general continuum of
values (fig. 3).
Group 1, the coarsest samples 31-2a, 31-2f, 31-2g
and 33e, show an M range of 45-120 microns and a Cu
range of 1-4 mm. These sediments would be classified
as a type III “graded” (grains maintained in the flow by
turbulence) suspension with bed rolled grains by a
moderately turbulent flow, and 33e with higher