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The dramatic global extinction of 35%-50% of benthic foraminifera species in the deep sea in the latest Paleocene and associated negative excursions in delta(13)C and delta(18)O may be related to spreading of warm, saline bottom water from subtropical Tethyan shallow regions over the sea floor worldwide, Our study of neritic sections in Egypt shows that in the southern shallow Tethys, a prominent long-term change in bottom-water chemistry, sedimentation, and benthic foraminifera fauna was initiated at the time when the deep-sea benthic extinction event (BEE) took place, Bottom-water delta(13)C values on the Tethyan shelf show a sudden 3.0 parts per thousand negative shift at this event; however, contrary to the deep sea, in which the delta(13)C excursion was of short duration, Tethyan delta(13)C values did not fully return to preboundary values, but remained depressed by similar to 1.5 parts per thousand for at least 1 m.y. The delta(13)C values at the Egyptian shelf during the BEE are much lower than would be expected if this was a source region for global deep water, The delta(18)O values indicate no significant change in bottom-water salinity or temperature at the BEE. The long-lasting environmental changes that began on the Egyptian shelf at the BEE may be related to, for example, gateway reorganization along the Tethyan seaway. Paleogeographic changes possibly also triggered a change in the Loci of global deep-water formation; however, these loci must be sought in another part of the Tethys. ispartof: Geology vol:24 issue:4 pages:347-350 status: published |
