Environmental Engineering Reference
In-Depth Information
TABLE 7.1
Classification of Soils by Origin and Mode of Occurrence
Occurrence
Origin
Depositional
Primary
a
Secondary
b
Typical Material
c
Environment
Residual
In situ
Syenite
Saprolite
Low-activity clays and
Granite
granular soils
Diorite
Gabbro
Saprolite
High-activity clays
Basalt
Dolerite
Gneiss
Saprolite
Low-activity clays and
Schist
granular soils
Phyllite
Very soft rock
Sandstone
Thin cover depends on
impurities
Shales
Red
Thin clayey cover
Black, marine
Friable and weak mass, high-
activity clays
Carbonates
Pure
No soil, rock dissolves
Impure
Low-to-high activity clays
Colluvial
Slopes
Falls
Talus
Boulders to cobbles
Slides
Structure preserved
Parent material
Flows
Structure destroyed
Parent or mixed material
Alluvial
Fluvial
Streambed
Youthful stage
Very coarse granular
Mature, braided
Coarse granular
Old age, meandering
Coarse to fine, loose
Alluvial fan
Coarse to fine, loose
Floodplain
Point bar
Medium-fine sand, loose
Clay plugs
Soft clay
Natural levees
Coarse-fine sand, loose
Backswamp
Organic silt and clay
Lateral accretion
Medium granular, loose
Rejuvenated
Buried valleys
Coarse granular, dense
Terraces
Variable, medium dense
Estuarine
Delta
Parent delta
Variable, soft or loose
Subdelta
Chiefly sands, loose
Prodelta
Soft clays
Estuary
Primarily fine grained
grading to coarse
Lacustrine
Lakes
Various forms
Primarily fine grained
Swamps and marshes
Organic soils
Playas
Evaporites
Fine grained with salts
Coastal
Marine
Spits
Coarse-fine sand, medium
depositions coast
dense
Barrier beach
Coarse-fine sand, dense
Tidal marsh
Very soft organics
Beach ridges
Coarse-fine sand, dense
Marine
Offshore
Varies with water
Marine clays
depth and
Silica sands
currents
Carbonate sands
Coastal plain
Various, preconsolidated
Aeolian
Ground moisture
Dunes
Medium-fine sand, loose
deficient
Sand sheets
Medium-fine sand, loose
Loess
Silts, clays, lightly cemented
Volcanic clay
Expansive clays
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Continued
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