Environmental and depositional changes across the Late Cenomanian
oceanic anoxic event (OAE2) in the Sinai, Egypt, are examined based on
biostratigraphy, mineralogy, delta(13)C values and phosphorus analyses.
Comparison with the Pueblo, Colorado, stratotype section reveals the
Whadi El Ghaib section as stratigraphically complete across the late
Cenomanian-early Turonian. Foraminifera are dominated by high-stress
planktic and benthic assemblages characterized by low diversity,
low-oxygen and low-salinity tolerant species, which mark shallow-water
oceanic dysoxic conditions during OAE2. Oyster biostromes suggest
deposition occurred in less than 50 m depths in low-oxygen, brackish,
and nutrient-rich waters. Their demise prior to the peak delta(13)C
excursion is likely due to a rising sea-level. Characteristic OAE2
anoxic conditions reached this coastal region only at the end of the
delta(13)C plateau in deeper waters near the end of the Cenomanian.
Increased phosphorus accumulations before and after the delta(13)C
excursion suggest higher oxic conditions and increased detrital input.
Bulk-rock and clay mineralogy indicate humid climate conditions,
increased continental runoff and a rising sea up to the first delta(13)C
peak. Above this interval, a dryer and seasonally well-contrasted
climate with intermittently dry conditions prevailed. These results
reveal the globally synchronous delta(13)C shift, but delayed effects of
OAE2 dependent on water depth.