The Tethys is a critical region for investigating the mechanism(s) of
the Paleocene-Eocene global change, because of its potential in
producing warm saline water masses, a possible driving force for the
deep ocean warming at this time. To examine climatic, oceanographic and
ecologic changes in the deep Tethys basin, we conducted high resolution
faunal, isotopic and mineralogic analyses across the P-E transition at
the Alamedilla section (paleodepth between 1000 m and 2000 m) in
southern Spain. At this location, foraminiferal delta(18)O values show
little temperature change in surface waters, but a 4 degrees C warming
in bottom waters. Comparison with deep-sea sites indicates that
Antarctic intermediate water was consistently colder than Tethys bottom
water. During the course of the P-E global change, however, the
temperature difference between these two water masses was reduced from a
previous 5 degrees C to 3 degrees C. Clay mineralogic analyses at the
Alamedilla section indicate increased aridity in the Tethys region that
contrasts with a humid episode on Antarctica during high-latitude
warming. Foraminiferal delta(13)C values at Alamedilla show a negative
excursion of 1.7 parts per thousand in both surface and bottom waters
with little change in the vertical delta(13)C gradient. Accumulation of
organic and inorganic carbon in sediments decreased significantly,
suggesting changes in the size and structure of the oceanic carbon
reservoir. Associated with these climatic and oceanographic changes is a
reorganization of the Tethys ecosystem, a benthic foraminiferal mass
extinction, and planktonic foraminiferal assemblages marked by increased
species turnover rates and high relative abundance of short-lived,
opportunistic species that suggest increased instability.