Soils in their environment - Fundamentals of the Physical Environment - page 443

c m pH

Figure 18.11
Profile of a Humic
Groundwater Gley soil.

0

Surface
accumulation
of peat

H 6.1

Ah 6.0

Winter water table

30

Mobilization
and local
precipitation
of ferric iron

Cg1 6.1

Fluctuating
Gr oundwa ter

Summer water table

60

6.6

Cg2

Reduction to
ferrous iron

90

Humic Groundwater
Gley

Plate 18.15 Groundwater Gley (FAO: Eutric Gleysol) in
carse (estuarine clay) in Stirlingshire, Scotland. Dull bluish
colours at the base indicate anaerobic conditions (Cg), whilst
brown horizons above (Ag and Bg) have brighter colours
indicating better aeration and oxidizing conditions, principally
in summer.
Photo: Ken Atkinson