1.4 Basin Morphology
relief continental environments - lowlands - shallow
seas - deep sea.
Similarly, the sedimentation rate tends to decrease
from highland continental basins to the central parts
of large oceanic basins.
Basins with low sedimentation rates tend to accumulate sediments relatively rich in biogenic components. Such basins may persist for long time periods
and are therefore often markedly affected by
synsedimentary tectonic movements.
Chemical sediments (evaporites) of some extent
commonly form in lowlands (lakes) and special
portions of adjacent shallow seas, but rarely in the
other depositional environments.
- The sedimentary facies of rnany basin fills do not
reflect tectonic basin evolution and specific structural elements. Only in some basin types and/or
during the most rapid phase of basin evolution do
tectonic movements direetly control sedimentary
faeies. However, the geometry of basin fills, sedimentation rates, and syn- and post-depositional deformations eharaeterize the tectonic style and evolution of the basin eonsidered.
1.4.7 Summary (Basin Classification)
Sedimentary basins originate from various
endogenie processes and can be classified on the
basis ofplate tectonie models. The basin-generating forces also determine the overall geometry of
the entire basin fill.
However, the depositional environments and
sedimentary facies of the basins are to a large
extent eontrolled by exogenic processes (e.g.
terrigenous sediment influx, autoehthonous sediment produetion, hydrographie regime of the
basin, sediment distribution, ete.).
15
1.4.6 Facies Architecture
The prineipal sediment eharaeteristies of the various
depositional environments include features on different
scales. These range from large-seale phenomena,
relevant to the facies distribution in the total basin, to
micro-seale properties which are studied in a single
rock speeimen. As Allen (1983) and Miall (1985) have
pointed out, the sedimentary basin fill often displays a
certain type of stratigraphic architeeture, i.e., larger
units are built up by a number of srnaller, basic units.
In single outerops, generally only the smaller seale
units can be observed, whieh are often not suffieiently
diagnostie for the reeognition of the true nature of the
total basin fill or a large part of it.
The brief surnmaries for the eommon depositional
environments presented in Chapters 2 through 6 are
largely based on these principles. They preferentially
show field and outcrop phenomena and how these fit
into a larger scale faeies model. Micro-seale features
and processes are only described in special eases.
This means that (I) similar sediment types ean
oeeur in basins of eompletely different tectonic
origin, and (2) an additional basin classifieation
is needed whieh is based on the various
depositional environments.
Certain basin fills refleet pre- and syndepositional
tectonies. To understand both basin-forming
tectonics and depositional environments, basin
fills should be studied at different seales (outerops, drillholes, geometry ofthe total basin fill).
relief continental environments - lowlands - shallow
seas - deep sea.
Similarly, the sedimentation rate tends to decrease
from highland continental basins to the central parts
of large oceanic basins.
Basins with low sedimentation rates tend to accumulate sediments relatively rich in biogenic components. Such basins may persist for long time periods
and are therefore often markedly affected by
synsedimentary tectonic movements.
Chemical sediments (evaporites) of some extent
commonly form in lowlands (lakes) and special
portions of adjacent shallow seas, but rarely in the
other depositional environments.
- The sedimentary facies of rnany basin fills do not
reflect tectonic basin evolution and specific structural elements. Only in some basin types and/or
during the most rapid phase of basin evolution do
tectonic movements direetly control sedimentary
faeies. However, the geometry of basin fills, sedimentation rates, and syn- and post-depositional deformations eharaeterize the tectonic style and evolution of the basin eonsidered.
1.4.7 Summary (Basin Classification)
Sedimentary basins originate from various
endogenie processes and can be classified on the
basis ofplate tectonie models. The basin-generating forces also determine the overall geometry of
the entire basin fill.
However, the depositional environments and
sedimentary facies of the basins are to a large
extent eontrolled by exogenic processes (e.g.
terrigenous sediment influx, autoehthonous sediment produetion, hydrographie regime of the
basin, sediment distribution, ete.).
15
1.4.6 Facies Architecture
The prineipal sediment eharaeteristies of the various
depositional environments include features on different
scales. These range from large-seale phenomena,
relevant to the facies distribution in the total basin, to
micro-seale properties which are studied in a single
rock speeimen. As Allen (1983) and Miall (1985) have
pointed out, the sedimentary basin fill often displays a
certain type of stratigraphic architeeture, i.e., larger
units are built up by a number of srnaller, basic units.
In single outerops, generally only the smaller seale
units can be observed, whieh are often not suffieiently
diagnostie for the reeognition of the true nature of the
total basin fill or a large part of it.
The brief surnmaries for the eommon depositional
environments presented in Chapters 2 through 6 are
largely based on these principles. They preferentially
show field and outcrop phenomena and how these fit
into a larger scale faeies model. Micro-seale features
and processes are only described in special eases.
This means that (I) similar sediment types ean
oeeur in basins of eompletely different tectonic
origin, and (2) an additional basin classifieation
is needed whieh is based on the various
depositional environments.
Certain basin fills refleet pre- and syndepositional
tectonies. To understand both basin-forming
tectonics and depositional environments, basin
fills should be studied at different seales (outerops, drillholes, geometry ofthe total basin fill).