2.2
The Lagoon Bottom Around BAKER GZ
The following is an excerpt from Reference C-2 that describes the
lagoon bottom surrounding the BAKER target area.
The characteristic sediment in the target -area,
prior to Test B, consisted chiefly of remains of the
calcareous alga Halimeda.
This alga, green when living
consists of flat oval plates, 2mm. to 5mm. in diameter,
joined together in series like a string of beads.
When
the plant dies, the green tissue decomposes and the
plates fall apart, leaving a residue of small white or
pale brown plates resembling uncooked rolled oats.
With this Halimeda debris there usually is admixed a
variable amount of mud (silt and clay-sized particles),
sand, and shells.
Five cores taken in the vicinity of the explosion
point two weeks after Test B in the summer of 1946
showed that this sediment no longer occurred in the
target area.
Instead, a layer of mud covered the
bottom, with coarser material below.
However, the 33
cores taken during the 1947 resurvey show that the
typical sequence in the target area now is as follows:
A,
A top layer of "target area" mud
(see Figure
C-3), grading through a thin transition zone into B.
A layer of silt and
sand, the coarseness increasing
turn grades into C.
fine
with
to coarse silty
depth.
This in
A layer of clean, white Halimeda debris, with
occasional fragments of green Halimeda.
usually with a sharp contact, on -
This
D.
Pale tan or
admixed mud and sand.
debris
The bottom layer
brownish
(D)
Halimeda
of this
sediment of the target area
The
layers
Baker
three
explosion.
top
It
usually
(A,
8B,
with
sequence appears
be the original
the
rests,
D
is
not
4¢sic})
to
prior to
radioactive.
apparently
represent material that was stirred up by the explosion
and subsequently settled out roughly in a sequence
9000063
C-4