a
b
Bouma (1962)
Divisions
Interturbidite
(generally shale )
Plane pa rallel
lam inae
Turbidity Currents
63
Interpretation
Pel ag ic
sed imentation or
fine grained, low
density turbidity
current deposition
0>
C
en
0(1)
~E
u-(1)0>
-o~
~ I ~
0° :::l'+-0
o
'-(.!)
Fig. 2.1S a, b. Origin of graded layers. a Experiment of Ph. H. Kuenen. J Turbid, sediment-laden
water is introduced into the tank; 2 water in tank remains still and clear over the bottom, where the
denser muddy water rushes downslope; 3 turbulent front of the turbidity current. Depending on its
strength, a turbidity current can erode and redeposit enormous amounts of sediment. [J. Gilluly et
aI. , 1968 , Principles of geology. W. H. Freeman. San Francisco, after photos by H. S. Bell, Cal.
Tech.] b Standard sequence of divisions in a turbidite laye . as proposed by A. H. Bouma. The lower
parI is the graded bed. produced by a turbidity current. The upper pari results from " normal"
sedimentation; it contains almost all the geologic time represented. Sudden loading of these pelagic
clays may produce "load casts". High velocities of the currents are indicated by drag and flute marks
at the base of the turbidite. [G. V. Middleton, M. A. Hampton. 1976, in D. 1. Stanley, D. J. P. Swift.
Marine sediment transport and environmental management, John Wiley, New York.]
Before the turbidite hypothesis became a standard tool in the interpretation of
sediments, the "desolate thousand-fold alternation of sandstone, limestone, and shale"
which faced the alpine geologist in the flysch was a complete mystery. Now these
alternations are generally regarded as a record of pelagic sedimentation with periodic
b
Bouma (1962)
Divisions
Interturbidite
(generally shale )
Plane pa rallel
lam inae
Turbidity Currents
63
Interpretation
Pel ag ic
sed imentation or
fine grained, low
density turbidity
current deposition
0>
C
en
0(1)
~E
u-(1)0>
-o~
~ I ~
0° :::l'+-0
o
'-(.!)
Fig. 2.1S a, b. Origin of graded layers. a Experiment of Ph. H. Kuenen. J Turbid, sediment-laden
water is introduced into the tank; 2 water in tank remains still and clear over the bottom, where the
denser muddy water rushes downslope; 3 turbulent front of the turbidity current. Depending on its
strength, a turbidity current can erode and redeposit enormous amounts of sediment. [J. Gilluly et
aI. , 1968 , Principles of geology. W. H. Freeman. San Francisco, after photos by H. S. Bell, Cal.
Tech.] b Standard sequence of divisions in a turbidite laye . as proposed by A. H. Bouma. The lower
parI is the graded bed. produced by a turbidity current. The upper pari results from " normal"
sedimentation; it contains almost all the geologic time represented. Sudden loading of these pelagic
clays may produce "load casts". High velocities of the currents are indicated by drag and flute marks
at the base of the turbidite. [G. V. Middleton, M. A. Hampton. 1976, in D. 1. Stanley, D. J. P. Swift.
Marine sediment transport and environmental management, John Wiley, New York.]
Before the turbidite hypothesis became a standard tool in the interpretation of
sediments, the "desolate thousand-fold alternation of sandstone, limestone, and shale"
which faced the alpine geologist in the flysch was a complete mystery. Now these
alternations are generally regarded as a record of pelagic sedimentation with periodic