Environmental Engineering Reference
In-Depth Information
Taplow gravels
Flood plain gravels
Alluvium
London clay
N
Paddington
Paddington
station
Marble
arch
Piccadily
Waterloo
bridge
Hyde
park
Charing
cross
Waterloo
station
South
bank
Green
park
St.
Jame's
park
St. Georges
hospital
Buckingham
palace
Albert
hall
Houses
of
parlia-
ment
Victoria
Victoria
station
0
1/4
1/2
3/4
1 mile
(a)
Flood
plain
gravels
Made ground
and alluvium
Taplow gravels
+100
O.D.
-100
-200
-300
ft.
0
London clay
W
d read
ing b
T
Chalk
an
1/4
1/2
3/4
1 mile
(b)
FIGURE 7.56
Geologic map and section from Paddington to the south bank of the Thames, London: (a) geologic map
showing the position of the three sites of
Figure 7.57
and (b) geologic section. (From Skempton, A. W. and
Henkel, D. J.,
Proceedings of the 4th International Conference on Soil Mechanics and Foundation Engineering
, London,
1957, p. 100. With permission.)
7.4.5
Lacustrine Environment (Nonglacial)
General
Materials deposited in a lake environment are termed lacustrine, and include granular
soils along the shoreline, in the forms of beaches, dunes, and deltas, and silts and clays fill-
ing the lake basin.
In geologic time many lakes are relatively short-lived features terminating as large flat
areas, swamps, and marshes. Land areas that were former lake beds can be expected to
present difficult foundation conditions.
Origin and Occurrence of Lakes
Significance
Because lakes occur in depressions, which normally do not result from erosion activity, the
cause of their existence aids in understanding regional geology. Numerous lakes are made
by beavers and humans; the natural causes are described below.
Tectonic Basins
Many of the largest lakes are formed from movements of the Earth's crust, which cause
faulting, folding, and gentle uplifting of the surface. Uplifting can cut off a portion of the
