89
23942405,/2385,, ratios of 27.5 and 33.3 found in the two deeper segments of
the core are similar to several other ratios found in surface sediments of the
lagoon which were collected away from the region south of Tewa Crater.
9.3-2
Northwest Lagoon Quadrant Profiles
Three sediment cores were collected from this region of
the lagoon (stations B-2, B-20 and B-21).
The distribution of radionuclides
in surface sediments (section 5) and the distribution of finely divided sediments (section 5.3) in this region of the lagoon have been discussed previously.
Pulverized sediments were found at all three stations, although the radionuclide concentrations were significantly lower at Station B-21 than at B-20
and B-2.
The distribution of
239+2405
>
24]
Am and
tected at Station B-2 is shown in Figure 23.
60
~“Co in the sediment core col-
Several features of this long
core were found to be similar to features in other sediment cores collected
from the northwest quadrant.
The distribution of
24] Am
2394240, | , 155 Eu and 137 Cs concentrations
measured in this core were very similar, except that: (1) the absolute concentrations of
137
Cs measured were lower than the
by a factor of 10, and (2) the
2394240
24)
Am and
155
Eu concentrations
Pu concentrations measured were slightly
more irregular with depth than the concentrations measured for 24 an or W95ey,
In the top 11 cm of the core, the concentrations of
and
239+240
Pu,
24]
An,
155,
137 Cs decrease regularly with depth to 50% of their respective concentra-
tions as measured in surface sediment.
The sediments in this part of the core
consisted of mixtures of pulverized material and Halimeda, beginning in the
8-10 cm section.
In the 12-26 cm regions of the core, the concentrations of
239+240
155
Pu,
241
Am
Eu and
137
Cs decreased nearly logarithmically with depth.
In the 28-38 cm region of the core, the concentrations again decreased slowly