34
H. Khozyem
anoxic condition that could be linked to oxygen exhalation due to partial oxidation
of methane, this anoxia is marked in Dababiya by a negative Ce-anomaly and the
precipitation of individual euhedral pyrite crystals within the sediments, and (3)
methane oxidation to CO 2 at the water/atmosphere interface.
The excess of CO 2 in the atmosphere is acting as greenhouse gases and increases
the weathering of silicate rocks. This period of increased weathering is observed
at the Dababiya GSSP 60 cm above the P/E boundary and is characterized by high
phyllosilicate contents including kaolinite, high CIA and CIW, high Ti, Cr and K
input, δ
13 C Carb minimum value (Fig. 8). The top of that interval is characterized by
anoxic conditions marked by (1) a negative Ce-anomaly, (2) enrichment of redoxsensitive trace elements and their ratios (V, U, V/Cr, Ni/Co, V/V + Ni), (3) abundant
pyrite framboids (>2 μm in diameter), which indicate anoxic conditions within the
water column, (4) increased productivity sensitive trace elements (Pb, Zn, Cu, Co
and Mo) that could only be enriched under anoxic conditions associated with high
organic matter accumulation leading to the development of anoxic conditions, (5) a
strong and persistent decrease in δ
15 N org reflecting significant bacterial activity such
as sulfur reducing and cyanobacteria activities as indicated by low N isotope and the
presence of EPS-like structures within the PETM interval; and (6) δ
13 C org minimum
recorded value.
The PETM recovery phase starts at the top of the interval marked by intense
weathering (top of the upper anoxic level). The high nutrients input delivered into
the ocean reactivates the biological pump leading to the re-establishment of more
Fig. 8 CIA and CIW curve indicates the intensive weathering during the PETM, Ce- anomaly and
the redox parameters showing the different anoxic intervals recorded at the Dababiya GSSP, and
phosphorus as an indicator of Paleoproductivity at the recovery interval. The SEM pictures show
the observed features during the anoxic interval of the PETM in Dababiya GSSP. Modified after
[138]
H. Khozyem
anoxic condition that could be linked to oxygen exhalation due to partial oxidation
of methane, this anoxia is marked in Dababiya by a negative Ce-anomaly and the
precipitation of individual euhedral pyrite crystals within the sediments, and (3)
methane oxidation to CO 2 at the water/atmosphere interface.
The excess of CO 2 in the atmosphere is acting as greenhouse gases and increases
the weathering of silicate rocks. This period of increased weathering is observed
at the Dababiya GSSP 60 cm above the P/E boundary and is characterized by high
phyllosilicate contents including kaolinite, high CIA and CIW, high Ti, Cr and K
input, δ
13 C Carb minimum value (Fig. 8). The top of that interval is characterized by
anoxic conditions marked by (1) a negative Ce-anomaly, (2) enrichment of redoxsensitive trace elements and their ratios (V, U, V/Cr, Ni/Co, V/V + Ni), (3) abundant
pyrite framboids (>2 μm in diameter), which indicate anoxic conditions within the
water column, (4) increased productivity sensitive trace elements (Pb, Zn, Cu, Co
and Mo) that could only be enriched under anoxic conditions associated with high
organic matter accumulation leading to the development of anoxic conditions, (5) a
strong and persistent decrease in δ
15 N org reflecting significant bacterial activity such
as sulfur reducing and cyanobacteria activities as indicated by low N isotope and the
presence of EPS-like structures within the PETM interval; and (6) δ
13 C org minimum
recorded value.
The PETM recovery phase starts at the top of the interval marked by intense
weathering (top of the upper anoxic level). The high nutrients input delivered into
the ocean reactivates the biological pump leading to the re-establishment of more
Fig. 8 CIA and CIW curve indicates the intensive weathering during the PETM, Ce- anomaly and
the redox parameters showing the different anoxic intervals recorded at the Dababiya GSSP, and
phosphorus as an indicator of Paleoproductivity at the recovery interval. The SEM pictures show
the observed features during the anoxic interval of the PETM in Dababiya GSSP. Modified after
[138]