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Titel |
"OAE 3" – regional Atlantic organic carbon burial during the Coniacian–Santonian |
VerfasserIn |
M. Wagreich |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1814-9324
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Digitales Dokument |
URL |
Erschienen |
In: Climate of the Past ; 8, no. 5 ; Nr. 8, no. 5 (2012-09-20), S.1447-1455 |
Datensatznummer |
250005834
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Publikation (Nr.) |
copernicus.org/cp-8-1447-2012.pdf |
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Zusammenfassung |
The Coniacian–Santonian time interval is the inferred time of oceanic anoxic
event 3 (OAE 3), the last of the Cretaceous OAEs. A detailed look on the
temporal and spatial distribution of organic-rich deposits attributed to OAE
3 suggests that black shale occurrences are restricted to the equatorial to
mid-latitudinal Atlantic and adjacent basins, shelves and epicontinental
seas like parts of the Caribbean, the Maracaibo Basin and the Western
Interior Basin, and are largely absent in the Tethys, the North Atlantic,
the southern South Atlantic, and the Pacific. Here, oxic bottom waters
prevailed as indicated by the widespread occurrence of red deep-marine CORBs
(Cretaceous Oceanic Red Beds). Widespread CORB sedimentation started during
the Turonian after Oceanic Anoxic Event 2 (OAE 2) except in the Atlantic
realm where organic-rich strata continue up to the Santonian. The temporal
distribution of black shales attributed to OAE 3 indicates that organic-rich
strata do not define a single and distinct short-time event, but are
distributed over a longer time span and occur in different basins during
different times. This suggests intermittent and regional anoxic conditions
from the Coniacian to the Santonian. A comparison of time-correlated
high-resolution δ13C curves for this interval indicates several
minor positive excursions of up to 0.5‰, probably as a result of massive
organic carbon burial cycles in the Atlantic. Regional wind-induced
upwelling and restricted deep basins may have contributed to the development
of anoxia during a time interval of widespread oxic conditions, thus
highlighting the regional character of inferred OAE 3 as regional Atlantic
event(s). |
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