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Titel |
Phanerozoic environments of black shale deposition and the Wilson Cycle |
VerfasserIn |
J. Trabucho-Alexandre, W. W. Hay , P. L. Boer |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1869-9510
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Digitales Dokument |
URL |
Erschienen |
In: Solid Earth ; 3, no. 1 ; Nr. 3, no. 1 (2012-02-02), S.29-42 |
Datensatznummer |
250000833
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Publikation (Nr.) |
copernicus.org/se-3-29-2012.pdf |
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Zusammenfassung |
The spatial and temporal distribution of black shales is related to the
development of environments in which they accumulate and to a propitious
combination of environmental variables. In recent years, much has been done
to improve our understanding of the mechanisms behind the temporal
distribution of black shales in the Phanerozoic and of the environmental
variables that result in their deposition. However, the interpretation of
ancient black shale depositional environments is dominated by an
oversimplistic set of three depositional models that do not capture their
complexity and dynamics. These three models, the restricted circulation, the
(open) ocean oxygen minimum and the continental shelf models, are an
oversimplification of the variety of black shale depositional environments
that arise and coexist throughout the course of a basin's Wilson Cycle, i.e. the
dynamic sequence of events and stages that characterise the evolution of
an ocean basin, from the opening continental rift to the closing orogeny. We
examine the spatial distribution of black shales in the context of the
Wilson Cycle using examples from the Phanerozoic. It is shown that the
geographical distribution of environments of black shale deposition and the
position of black shales in the basin infill sequence strongly depend on
basin evolution, which controls the development of sedimentary environments
where black shales may be deposited. The nature of the black shales that are
deposited, i.e. lithology and type of organic matter, also depends on basin
evolution and palaeogeography. We propose that in studies of black shales
more attention should be given to the sedimentary processes that have led to
their formation and to the interpretation of their sedimentary environments. |
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