Two shallow water late Cenomanian to early Turonian sequences of NE
Egypt have been investigated to evaluate the response to OAE2. Age
control based on calcareous nannoplankton, planktic foraminifera and
ammonite biostratigraphies integrated with delta(13)C stratigraphy is
relatively good despite low diversity and sporadic occurrences. Planktic
and benthic foraminiferal faunas are characterized by dysoxic, brackish
and mesotrophic conditions, as indicated by low species diversity, low
oxygen and low salinity tolerant planktic and benthic species, along
with oyster-rich limestone layers. In these subtidal to inner neritic
environments the OAE2 delta(13)C excursion appears comparable and coeval
to that of open marine environments. However, in contrast to open marine
environments where anoxic conditions begin after the first delta(13)C
peak and end at or near the Cenomanian-Turonian boundary, in shallow
coastal environments anoxic conditions do not appear until the early
Turonian. This delay in anoxia appears to be related to the sea-level
transgression that reached its maximum in the early Turonian, as
observed in shallow water sections from Egypt to Morocco. (C) 2011
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