| Title: | Benthic foraminiferal extinctions across mid Cretaceous OAES: Evolutionary turn-over or rock record bias? |
| Author: | Ann Holbourn |
| Date Submitted: | 05/01/2002 |
| Address: | Olshausenstr. 40
Kiel
Germany
24118
|
| Phone: | 49-431-880-2924 |
| Email: | ah@gpi.uni-kiel.de |
| Co-Authors: | Kuhnt, Wolfgang, IfG, Christian Albrechts University, 24118 Kiel, Olshausenstr. 40 Germany |
| Affiliation: | IfG, Christian Albrechts University |
| | |
| Abstract URL: | http://cis.whoi.edu/science/GG/ccod/viewAbstracts.cfm?RefNumber=19725592 |
| Keywords: | mid-Cretaceous, benthic foraminifers, Oceanic Anoxic Events, evolution, OAE |
| Abstract: | We examined records of well preserved benthic foraminiferal
assemblages across Cretaceous oceanic anoxic events OAE 1a-c
and OAE2 from bathyal and abyssal DSDP/ODP Sites (Sites
1049, 1052, Blake Nose, Site 551, Goban Spur, Site 603, and
Site 641) and from bathyal to neritic onshore sections in
Morocco, Spain, Southeast France and North Germany.
Diversity, taxonomic composition and preservation potential
of benthic foraminiferal assemblages at shelf localities are
strongly influenced by changes in paleo-water depth,
particularly at times of major sea-level change. Thus, most
of the observed faunal changes at shelf sites express
environmental change and taphonomic bias, rather than true
extinction and radiation events. We found no evidence for a
major benthic foraminiferal turn-over during OAE1 and OAE2
both at middle and upper bathyal sites. Most taxa recorded
at these locations have stratigraphic ranges extending
across oceanic anoxic events. The changes in biofacies
recorded across the OAEs coincide with changes in
hydrography and sedimentological facies. By contrast,
abyssal benthic foraminifers underwent a marked radiation
after the late Cenomanian OAE-2 in the Atlantic Ocean and
the Mediterranean Tethys, which may be triggered by a
general change towards better oxygenated deep-wate |
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