Paleontological studies on the Upper Paleocene-Lower Eocene succession at Darb Gaga, southeastern
Kharga Oasis, Western Desert, Egypt document the changes associated with the Paleocene-Eocene
Thermal Maximum (PETM), such as 1) a radical alteration of the relative and absolute abundance of
planktonic foraminifera; 2) a massive occurrence of the excursion planktonic foraminiferal taxa; 3) a
widespread deposition of calcarenite yielding atypical (extremely high) faunal abundance associated
with the younger phase of warming; and 4) a concentration of coprolites associated with the middle
phase of warming. We also document the Lowest Occurrence (LO) of dimorphic larger benthic and
excursion foraminifera during the earlier phase of warming at Darb Gaga, as recorded in Bed 1 of the
Dababiya Quarry Member. The absence of these faunas in Bed 1 at Dababiya (the GSSP for the P/E
Boundary) is likely to be due to both intense deficiency in dissolved oxygen and massive carbonate
dissolution. Only remains (fish remains) of faunas that can tolerate the toxicity produced by low oxygen
conditions are found in the stratigraphic record of this (oldest) phase at Dababiya.
The Dababiya Quarry Member (DQM) at Darb Gaga reflects the unfolding of the sedimentary and biotic
changes associated with the PETM global warming at, and following, the Paleocene/Eocene boundary on
the southern Tethys platform. The changes began with a rapid increase in bottom and “intermediate”
water temperature. The temperature increase was accompanied by removal of oxygen during the early
and middle stages of warming. This led to the absence of both subbotinids and calcareous benthic
foraminifera in the early and second coprolite-bearing phases (Beds 2 and 3 of the DQM). Dissolution
seems to have no role during these stages as shown by the unusual abundance and good preservation of
the warm-tolerant Ac. sibaiyaensis. This species reaches its maximum abundance in Bed 2 where it exhibits
a broad range of size (63e250 mm) and shape that probably reflect optimal growth under the
warmest water conditions. Thus, we infer that temperature and dissolved oxygen content of the seawater
were the main factors controlling the distribution pattern(s) of the microplankton and microbenthos
during the PETM.