36
work demonstrating the complexity of the effects of
climate and sea-level change is discussed in Chaps.
12 and 13.
Developments in sediment transport mechanics,
bedform classification, flow regime concepts, and
quantitative geomorphology, on which the study of
paleohydraulics rests, have been summarized earlier
in this review. The remainder of this section contains
a brief discussion of some of the published applications of such knowledge to geological problems.
The fining-upward point-bar cycle has been the
most widely used paleohydraulic indicator, almost
since the genesis of the cycle as the product oflateral
accretion was first deduced in the early 1960s. The
discovery of '� f psildh11 cross-bedding and its interpretation as superimposed point-bar accretion
slopes helped to confirm this interpretation. Allen
(!965b) was the first to realize the paleohydraulic
significance of these cycles, in his study of the Old
Red Sandstone of Anglesey, North Wales:
"It appears that the streams which deposited the alluvial
fades were already substantial rivers on reaching
Anglesey. Each epsilon cross-stratified unit has been interpreted as a point-bar deposit. The thickness of such units
therefore corresponds to the stream channel depth at the
bankfull state (Wolman and Leopold 1957, pp. 92, 95), and
the mean unit thickness is 6 ft 3ln. Leopold and Maddock
(19_53, Appendix A} gave data leading to relationships
between stream wjdth, mean depth and drainage basin
area, and Hack (1957, p. 63) later presented an equation
connecting stream drainage area and stream length. When
the mean unit thickness is substituted for the mean channel depth in these relationships, it becomes statistically
very unlikely that the streams were less than 40 miles long,
including meanders, and 70 ft wide. Statistically the
streams were most likely to have been 400 miles long and
300 ft wide. Needless to say, these figures do not represent
predictions, for very many factors combine to determine
stream geometry, but are intended merely to convey the
probable order of importance of the streams which deposited the Old Red Sandstone of Anglesey."
Schumm (1968b) studied the present and prior
courses of the Murrumbidgee River, Australia, and
used the empirical geomorphological relationships
he had been developing for American and Australian
rivers to determine their various paleohydraulic
parameters. Sedimentological information, such as
sedimentary structures and facies relationships,
were not used in this work.
Eicher (1969) attempted to estimate river size,
discharge, and slope for a Cretaceous fluvial system
in Colorado. His only input datum consisted of
stream length, derived from regional paleogeoHistorical Background
graphic reconstruction, whence the other hydraulic
parameters were estimated using empirical geomorphological relationships. The building of an edifice
of interpretation from one or two items . of data by
using one estimated parameter as input for the next
estimate is one of the principal weaknesses of the
paleohydraulic method.
Allen (197Gb) used knowledge of bedform hydraulics and flow patterns in meander bends to deduce a generalized paleohydraulic model for a suite
of Devonian fining-upward cycles. No attempt was
made to proceed from this model to generalizations
regarding discharge or drainage area.
Cotter (1971) combined Allen's (1965b, !970b)
observations (in part quoted above) with Schumm's
family of equations to produce a paleohydraulic interpretation of a Cretaceous fluvial unit jn Utah,
including estimates of river length, drainage area,
discharge, sinuosity, and slope. Co�ter was aware of
the possible sources of error in his e$timates deriving
from differences in climate and vegetation in the
past, and emphasized that <
the environment interpreted in other ways."
Similar exercises to those quoted !;lbove were used
by Friend and Moody-Stuart (1972), Padgett and
Ehrlich (1976), Cant and Walker (1976), and Miall
(1976) in paleohydraulic reconstructions performed
on fluvial units in Spitzbergen, Morocco, Atlantic
and Arctic Canada. The routes throt:J.gh the various
equations differ in each case; fo r example, Friend
and Moody-Stuart (1972) and Cant and Walker
(1976) based much of their work on flow velocity
and power deductions derived from sedimentary
structures and grain size. Miall (1976) introduced a
sinuosity estimation based on paleocurrent measurements.
Baker ( 1973, 1978b) studied the catastrophic Lake
Missoula fl ood and provided a pa i eohydraulic reconstruction of some giant bedforms. Leeder (1973)
compiled data concerning epsilon cross-bedding,
and suggested some refinements of the methods for
using this structure and cycle thickness as paleohydraulic indicators. Bridge (1975) used much of the
earlier work on bedform hydraulics and flow patterns in a computer simulation of sedimentation in
meandering streams. Allen ( 1977) and Shaw and
Kellerhals (1977) examined ripples and antidunes,
respectively, as paleohydraulic indicators.
Several papers in Miall (1978a) reported field
studies of paleohydraulics, and this. section of the
work demonstrating the complexity of the effects of
climate and sea-level change is discussed in Chaps.
12 and 13.
Developments in sediment transport mechanics,
bedform classification, flow regime concepts, and
quantitative geomorphology, on which the study of
paleohydraulics rests, have been summarized earlier
in this review. The remainder of this section contains
a brief discussion of some of the published applications of such knowledge to geological problems.
The fining-upward point-bar cycle has been the
most widely used paleohydraulic indicator, almost
since the genesis of the cycle as the product oflateral
accretion was first deduced in the early 1960s. The
discovery of '� f psildh11 cross-bedding and its interpretation as superimposed point-bar accretion
slopes helped to confirm this interpretation. Allen
(!965b) was the first to realize the paleohydraulic
significance of these cycles, in his study of the Old
Red Sandstone of Anglesey, North Wales:
"It appears that the streams which deposited the alluvial
fades were already substantial rivers on reaching
Anglesey. Each epsilon cross-stratified unit has been interpreted as a point-bar deposit. The thickness of such units
therefore corresponds to the stream channel depth at the
bankfull state (Wolman and Leopold 1957, pp. 92, 95), and
the mean unit thickness is 6 ft 3ln. Leopold and Maddock
(19_53, Appendix A} gave data leading to relationships
between stream wjdth, mean depth and drainage basin
area, and Hack (1957, p. 63) later presented an equation
connecting stream drainage area and stream length. When
the mean unit thickness is substituted for the mean channel depth in these relationships, it becomes statistically
very unlikely that the streams were less than 40 miles long,
including meanders, and 70 ft wide. Statistically the
streams were most likely to have been 400 miles long and
300 ft wide. Needless to say, these figures do not represent
predictions, for very many factors combine to determine
stream geometry, but are intended merely to convey the
probable order of importance of the streams which deposited the Old Red Sandstone of Anglesey."
Schumm (1968b) studied the present and prior
courses of the Murrumbidgee River, Australia, and
used the empirical geomorphological relationships
he had been developing for American and Australian
rivers to determine their various paleohydraulic
parameters. Sedimentological information, such as
sedimentary structures and facies relationships,
were not used in this work.
Eicher (1969) attempted to estimate river size,
discharge, and slope for a Cretaceous fluvial system
in Colorado. His only input datum consisted of
stream length, derived from regional paleogeoHistorical Background
graphic reconstruction, whence the other hydraulic
parameters were estimated using empirical geomorphological relationships. The building of an edifice
of interpretation from one or two items . of data by
using one estimated parameter as input for the next
estimate is one of the principal weaknesses of the
paleohydraulic method.
Allen (197Gb) used knowledge of bedform hydraulics and flow patterns in meander bends to deduce a generalized paleohydraulic model for a suite
of Devonian fining-upward cycles. No attempt was
made to proceed from this model to generalizations
regarding discharge or drainage area.
Cotter (1971) combined Allen's (1965b, !970b)
observations (in part quoted above) with Schumm's
family of equations to produce a paleohydraulic interpretation of a Cretaceous fluvial unit jn Utah,
including estimates of river length, drainage area,
discharge, sinuosity, and slope. Co�ter was aware of
the possible sources of error in his e$timates deriving
from differences in climate and vegetation in the
past, and emphasized that <
the environment interpreted in other ways."
Similar exercises to those quoted !;lbove were used
by Friend and Moody-Stuart (1972), Padgett and
Ehrlich (1976), Cant and Walker (1976), and Miall
(1976) in paleohydraulic reconstructions performed
on fluvial units in Spitzbergen, Morocco, Atlantic
and Arctic Canada. The routes throt:J.gh the various
equations differ in each case; fo r example, Friend
and Moody-Stuart (1972) and Cant and Walker
(1976) based much of their work on flow velocity
and power deductions derived from sedimentary
structures and grain size. Miall (1976) introduced a
sinuosity estimation based on paleocurrent measurements.
Baker ( 1973, 1978b) studied the catastrophic Lake
Missoula fl ood and provided a pa i eohydraulic reconstruction of some giant bedforms. Leeder (1973)
compiled data concerning epsilon cross-bedding,
and suggested some refinements of the methods for
using this structure and cycle thickness as paleohydraulic indicators. Bridge (1975) used much of the
earlier work on bedform hydraulics and flow patterns in a computer simulation of sedimentation in
meandering streams. Allen ( 1977) and Shaw and
Kellerhals (1977) examined ripples and antidunes,
respectively, as paleohydraulic indicators.
Several papers in Miall (1978a) reported field
studies of paleohydraulics, and this. section of the