4
1 INTRODUCTION
sediments. Paleontology can be studied as a pure subject that concerns the evolution,
morphology, and taxonomy of fossils. In these pursuits the fossils are essentially removed from their sedimentological context.
The study of fossils within their sediments is a fruitful pursuit in two ways. Stratigraphy is based on the definition of biostratigraphic zones and the study of their relationship to lithostratigraphic units (Shaw, 1964; Ager, 1993; Pearson, 1998). Sound biostratigraphy is essential for regional structural and sedimentological analysis. The second
main field of fossil study is aimed at deducing their behavior when they were alive, their
habitats, and mutual relationships. This study is termed paleoecology (Ager, 1963).
Where it can be demonstrated that fossils are preserved in place they are an important
line of evidence in environmental analysis. Environmental analysis is the determination of the depositional environment of a sediment (Selley, 1996). This review of sedimentology has now moved from the purely biological aspect to facets that involve the
biological, physical, and chemical properties of sedimentary rocks. To determine the
depositional environment of a rock, it is obviously important to correctly identify and
interpret the fossils that it contains. At a very simple level a root bed indicates a terrestrial environment, a coral reef a marine one. Most applied sedimentology, however, is
based on the study of rock chips from boreholes. In such subsurface projects it is micropaleontology that holds the key to both stratigraphy and environment. The two aspects
of paleontology that are most important to sedimentology, therefore, are the study of
fossils as rock builders (as in limestones) and micropaleontology.
Aside from biology, environmental analysis is also based on the interpretation of the
physical properties of a rock. These include grain size and texture as well as sedimentary structures. Hydraulics is the study of fluid movement. Loose boundary hydraulics
is concerned with the relationship between fluids flowing over granular solids. These
physical disciplines can be studied by theoretical mathematics, experimentally in laboratories, or in the field in modern sedimentary environments. Such lines of analysis can
be applied to the physical parameters of an ancient sediment to determine the fluid processes that controlled its deposition (Allen, 1970). Environmental analysis also necessitates applying chemistry to the study of sediments. The detrital minerals of terrigenous rocks indicate their source and predepositional history. Authigenic minerals can
provide clues to both the depositional environment of a rock as well as its subsequent
diagenetic history. Environmental analysis thus involves the application of biology,
physics, and chemistry to sedimentary rocks.
Facies analysis is a branch of regional sedimentology that involves three exercises.
The sediments of an area must be grouped into various natural types or facies, defined
by their lithology, sedimentary structures, and fossils. The environment of each facies
is deduced and the facies are placed within a stratigraphic framework using paleontology and sequence stratigraphy. Like environmental analysis, facies analysis utilizes biology, chemistry, and physics. On a regional scale, however, facies analysis involves the
study of whole basins of sediment. Here geophysics becomes important, not just to study
the sedimentary cover, but to understand the physical properties and processes of the
crust in which sedimentary basins form. One particular contribution of physics to sedimentology has been the application of geophysics, specifically the seismic method to
sedimentary rocks. Improvements in the quality of seismic data in the 1970s lead to the
development of a whole new way of looking at sediments, termed sequence stratigra-
1 INTRODUCTION
sediments. Paleontology can be studied as a pure subject that concerns the evolution,
morphology, and taxonomy of fossils. In these pursuits the fossils are essentially removed from their sedimentological context.
The study of fossils within their sediments is a fruitful pursuit in two ways. Stratigraphy is based on the definition of biostratigraphic zones and the study of their relationship to lithostratigraphic units (Shaw, 1964; Ager, 1993; Pearson, 1998). Sound biostratigraphy is essential for regional structural and sedimentological analysis. The second
main field of fossil study is aimed at deducing their behavior when they were alive, their
habitats, and mutual relationships. This study is termed paleoecology (Ager, 1963).
Where it can be demonstrated that fossils are preserved in place they are an important
line of evidence in environmental analysis. Environmental analysis is the determination of the depositional environment of a sediment (Selley, 1996). This review of sedimentology has now moved from the purely biological aspect to facets that involve the
biological, physical, and chemical properties of sedimentary rocks. To determine the
depositional environment of a rock, it is obviously important to correctly identify and
interpret the fossils that it contains. At a very simple level a root bed indicates a terrestrial environment, a coral reef a marine one. Most applied sedimentology, however, is
based on the study of rock chips from boreholes. In such subsurface projects it is micropaleontology that holds the key to both stratigraphy and environment. The two aspects
of paleontology that are most important to sedimentology, therefore, are the study of
fossils as rock builders (as in limestones) and micropaleontology.
Aside from biology, environmental analysis is also based on the interpretation of the
physical properties of a rock. These include grain size and texture as well as sedimentary structures. Hydraulics is the study of fluid movement. Loose boundary hydraulics
is concerned with the relationship between fluids flowing over granular solids. These
physical disciplines can be studied by theoretical mathematics, experimentally in laboratories, or in the field in modern sedimentary environments. Such lines of analysis can
be applied to the physical parameters of an ancient sediment to determine the fluid processes that controlled its deposition (Allen, 1970). Environmental analysis also necessitates applying chemistry to the study of sediments. The detrital minerals of terrigenous rocks indicate their source and predepositional history. Authigenic minerals can
provide clues to both the depositional environment of a rock as well as its subsequent
diagenetic history. Environmental analysis thus involves the application of biology,
physics, and chemistry to sedimentary rocks.
Facies analysis is a branch of regional sedimentology that involves three exercises.
The sediments of an area must be grouped into various natural types or facies, defined
by their lithology, sedimentary structures, and fossils. The environment of each facies
is deduced and the facies are placed within a stratigraphic framework using paleontology and sequence stratigraphy. Like environmental analysis, facies analysis utilizes biology, chemistry, and physics. On a regional scale, however, facies analysis involves the
study of whole basins of sediment. Here geophysics becomes important, not just to study
the sedimentary cover, but to understand the physical properties and processes of the
crust in which sedimentary basins form. One particular contribution of physics to sedimentology has been the application of geophysics, specifically the seismic method to
sedimentary rocks. Improvements in the quality of seismic data in the 1970s lead to the
development of a whole new way of looking at sediments, termed sequence stratigra-