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Late Paleocene to middle Eocene clay mineral associations have been considered at fifteen locations from the Atlantic Ocean and the adjacent sector of the Southern Ocean, and compared to the results of previous investigations.

Globally warm climates and alternating wet and arid seasons are deduced from the widespread abundance of pedogenic smectite at every location. Near the Paleocene-Eocene boundary, enhanced humidity at high latitudes and in continental hinterlands is indicated by more abundant kaolinite, while in coastal areas from low and middle latitudes increased aridity resulted in more abundant palygorskite (and/or sepiolite).

Concomitant increases of kaolinite and fibrous clays are correlated with lower delta-O-18 of benthic and planktonic foraminifers in most oceanic areas, indicating that warmer conditions were associated with enhanced evaporation at low to middle latitudes, and increased precipitation at high latitudes. This is consistent with an improvement of meridional transfers of energy, which probably contributed to the compensation of the equator to pole thermal disequilibrium increased by the global warming.

During the middle Eocene, both kaolinite and palygorskite contents decreased at most southern locations, coeval with higher delta-O-18. Inferred cooling and reduced thermal exchanges especially characterized the southern high latitudes, and possibly resulted from plate tectonic evolution.