Journal of the Royal Society of Western Australia, 87(4), December 2004 
A: Soil 
No addition of wetland 
sediment above this surface 
A hortzon zone of organic enrichment, 
leaching, and extreme modification 
of parent material 
B hortzon: zone of lk_Mat1on, 
predpftatton, and moderate 
modWcatlon of parent material 
C hortzon: relatively unaltered 
parent material 
Soil development: 
chemical and physical 
transfprmdTlon of parent 
material from the surface 
downwards 
B: Infiltrational sediment deposit 
wetland sediment 
nflrtrartea Into sand 
below the surface 
via vadpse water delivery 
and/or bloturbation 
quartz sand 
at casement 
C: Accretionary sediment deposit 
c 
• "t • * 
O *> 4 • * O 
wetland sediment depositee 
on and vertically accreted 
above the surface of the 
quartz sqnd bqsement; 
sediment not derived from 
breakdown or basement sand 
burled surface of 
basement sand 
quartz sand 
at casement 
D: Combined infiltrational and 
accretionary sediment deposit 
r 
accumulation of 
weflana sediment 
above the burled surface 
of the basement sand 
. burled surface of 
basement sand 
, wetland sediment infiltrated 
below former surface 
O 
D 
Q 
ro 
8 o 
O O 
CD (D 
D 
Q 
o * 
O CD 
CD 
co 
Q 
D 
Cl 
CO 
o 
3 
u 
D 
CD CD 
Cl a 
5 " 3 
CD 
~ D 
o 
D 
Q 
O' 
O 
o 
CD 
o' 
D 
Q 
Figure 2. Concepts of soil versus sediment, as used in this study. A. Soil as a near surface alteration of parent material, using quartz sand 
as an example. B Sediment autochthonously formed within a wetland and infiltrated into a porous basement substrate, in this case 
mud infiltrating the sand.; this type of deposit is infiltrational sedimentation. C. Sediment autochthonously formed within a wetland 
"I 7 T abov f a basement substrate, in this case mud overlying sand; this type of deposit is accretionary sedimentation. 
autoch ^ ho I nousl y formed within a wetland and first infiltrated into a porous basement substrate, and then vertically 
accreted above a mud-clogged basement substrate. y 
142 
