B has been found as a concentrated trace element in sea water
and is absorbed by illite in the marine environments, while Ga is
derived from the weathered subsurface soils and is largely attacked
by smectite in terrigenous environments (Dominik and Stanley,
1993). B/Ga ratios could be used in the marine e terrestrial influenced
evaluation (Lan et al., 1987). B distribution ranges from
20 ppm to 26 ppm in the fluvial lithosomes, decreasing landwards.
Values range from 32 ppm to 48 ppm for shallow marine lithosomes
and 25 ppme41 ppm in the marginal marine lithosomes.
Ga ranges from 9 ppm to 14 ppm in the fluvial lithosomes, decreases
to 5ppme8ppm in the shallow marine lithosomes, and
7 ppme13 ppm in the marginal marine lithosomes. This is expected
for shallow and marginal marine lithosomes because of the limited
amount of terrigenous sediments with low accumulation of
smectite in which Ga is embedded (Keith and Degens, 1959; Lan
et al., 1987). The high and low values indicate regression and
transgression respectively which produces sequence of lithosomes
(Table 5).