AOC G3
Progress and Preliminary Results of the
Study of the Sediments of Rongelap Lagoon
W.
1.
Anikouchine
Size analysis by sieving (coarse fraction)
and settling
(fine fraction) has been completed on top, middle and
bottom segments of the 71 cores obtained from the lagoon .
in September 1959, and on the 32 samples of unconsoli-
dated Beach Rock (i.e. beach sand) obtained from Kabelle Island.
2.
These analyses yielded data which were punched on IBM
cards and fed into a 650 computer which calculated
statistical parameters for each sample.
include:
Mean particle size
The parameters
Sorting coefficients
Skewness measures
Kurtosis measures
Various plots of these parameters have been made in an
endeavor to discover sample groups which indicate distinct
sediment types.
In the event that such types exist, their
areal distribution will be plotted so that relationships
between sediment type and causative factors may be discerned.
Sorting has been plotted against mean particle size.
This plot shows beach sand as belonging to a distinct and
separate sediment type having a mean particle size of about
1/2 mm. and exhibiting quite good sorting.
Within this sedi-
ment type the sorting improves with decreasing average particle size.
The bulk of the middle and lower segments of the lagoon
core samples show a mean particle size of about 1/3 mm. with
considerably poorer sorting.
These samples also exhibit an
increase in sovting with decrease in average particle size.
The top inch of the cores show much more variation in these
parameters.
Many samples have mean particle sizes between
2 and 4 mm. and show sorting almost as good as in the beach
material.
A preliminary intrepetation of these observations
is that the sediments at the water-sediment interface are of
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