56
successions consist of sequences that are basin-wide
or regional in extent, and are developed by allogenic
mechanisms such as source-area tectonism, changes
in rates of basin subsidence, basin tilting, or eustasy.
As discussed later in this book, many fl uvial successions contain fining- and coarsening-upward sequences of regional extent. Correlation and mapping
of these sequences have led to a renewed interest in
vertical proflles, but have emphasized the need for
architectural methods to discriminate the various
cycles and sequences that have similar vertical profiles, but are of several different origins.
Mia!! (1978b) noted the paucity of studies of modern rivers, and the consequently limited scope of the
data base on which fluvial sedimentology rested.
Little has changed in the intervening years. There is
still considerable room for detailed sedimentological studies of the facies composition and architecture of modern rivers, and their relationship to flow
patterns and discharge characteristics. As noted by
N.D. Smith (pers. comm., 1995) many of the fl uvial
Historical Background
styles and facies models now used by sedimentologists (Chap. 8) are based largely on studies of the
ancient record.
Several areas of research that were active up to the
end of the 1980s, and are discussed at length in this
chapter, are not dealt with in detail elsewhere in this
book. Grain-size analysis, once thought to hold great
promise as a basin-analysis tool (Sect. 2.3.4), is a far
more cumbersome technique for field research than
facies analysis, requiring considerable laboratory
followup work, and the results have been shown to
be ambiguous or plain wrong. Paleohydraulic analysis reached a kind of plateau of development with the
work of Ethridge and Schumm (1978), and has been
pursued by very few workers since that time, presumably because of the pitfalls and imprecisions in
the method that were revealed by that review. However, some of the methods of paleohydraulic analysis
have been adapted for the investigation of sandbody geometry in the subsurface, and are described
in Chap. 10.
successions consist of sequences that are basin-wide
or regional in extent, and are developed by allogenic
mechanisms such as source-area tectonism, changes
in rates of basin subsidence, basin tilting, or eustasy.
As discussed later in this book, many fl uvial successions contain fining- and coarsening-upward sequences of regional extent. Correlation and mapping
of these sequences have led to a renewed interest in
vertical proflles, but have emphasized the need for
architectural methods to discriminate the various
cycles and sequences that have similar vertical profiles, but are of several different origins.
Mia!! (1978b) noted the paucity of studies of modern rivers, and the consequently limited scope of the
data base on which fluvial sedimentology rested.
Little has changed in the intervening years. There is
still considerable room for detailed sedimentological studies of the facies composition and architecture of modern rivers, and their relationship to flow
patterns and discharge characteristics. As noted by
N.D. Smith (pers. comm., 1995) many of the fl uvial
Historical Background
styles and facies models now used by sedimentologists (Chap. 8) are based largely on studies of the
ancient record.
Several areas of research that were active up to the
end of the 1980s, and are discussed at length in this
chapter, are not dealt with in detail elsewhere in this
book. Grain-size analysis, once thought to hold great
promise as a basin-analysis tool (Sect. 2.3.4), is a far
more cumbersome technique for field research than
facies analysis, requiring considerable laboratory
followup work, and the results have been shown to
be ambiguous or plain wrong. Paleohydraulic analysis reached a kind of plateau of development with the
work of Ethridge and Schumm (1978), and has been
pursued by very few workers since that time, presumably because of the pitfalls and imprecisions in
the method that were revealed by that review. However, some of the methods of paleohydraulic analysis
have been adapted for the investigation of sandbody geometry in the subsurface, and are described
in Chap. 10.