ABSTRACT: This work deals with the geochemical and mineralogical characteristics of the period representing the Paleocene-Eocene Thermal Maximum (PETM) succession, at both the Gabal Dababiya Paleocene-Eocene GSSP and the Gabal Owaina sections. At both sections, the sediments deposited during this interval contain varied amounts of phosphatized and silicified fish debris, pyrite framboids, pseudomorphs of hematite spherules, calcite and detrital minerals. At Gabal Dababiya, the PETM succession is characterized by strong anomalies inmost chalcophiles, especially in the lower part of the clay bed, aswell as in the coprolite-rich and the bone-bearing strata. In contrast, such concentrations of the chalcophile elements have not been recorded at G. Owaina. This leads to the conclusion that these trace elements are incorporated in the phosphatic components (fish debris and coprolites) and in the clay-fraction and/or organic matter. The association of SiO2*-excess, and P2O5 enrichment with an abundant radiolarian fauna and enrichment of the organic matter within the first three beds of Dababiya Quarry Beds, indicates high productivity and upwelling throughout their deposition. In the course of the upwelling activity,water rich in nutrients rose to the surface, enriching sediments with organic matter. The increased consumption of oxygen caused by the sinking of organic carbon to the bottom resulted in a redox front at or just above the sediment-water interface. At G. Owaina, the internal molds of radiolarians, as well as benthic and planktonic foraminifera which are represented by hematite spherules, are abundant in the post-PETM succession. This is an indication that silica and calcite dissolution, rather than low productivity accounts for the absence of opaline silica and biogenic calcite. Solutions resulting from the dissolution of siliceous and calcareous oozes may have penetrated lower layers and formed Ca-Si-rich components (silicified fish debris and Ca-Si-rich phase).
Files
You are not registered as a current subscriber. If your institution has an active subscription, contact us to ask for help with your computer's IP address. If you have an active personal subscription, log in.
Subscribe to Stratigraphy
| Online only | Added print | |
|---|---|---|
| Institutions | $280 | $340 |
| Individuals | $140 | $200 |