wAbstract
@The Paleocene-Eocene thermal maximum, a transient global warming
event, is characterized by extensive evidence of a more active
hydrological cycle. This includes a widespread pulse of kaolinite
accumulation on continental margins, viewed as the by-product
of either enhanced chemical weathering consistent with much more
humid conditions and/or increased erosion of previously deposited
laterites. The former would be more consistent with year-round
humid conditions, whereas the latter might be indicative of extreme
seasonal precipitation patterns. To assess these hypotheses, we
present a new high-resolution clay mineral assemblage and oxygen
isotope record from Bass River, a site on the New Jersey margin
(east coast of North America), which shows a sharp rise in the
abundance of kaolinite beginning a few thousand years before the
onset of the carbon isotope excursion (CIE). The ƒÂ18O
of the ƒ2-ƒÊm-size fraction exhibits a shift toward lower values
during the event. On the basis of a coeval shift in clay assemblages,
the shift in ƒÂ18OClays can be
explained by a shift in the relative percent of the primary clay
phases rather than a change in the isotopic composition of kaolinite,
as would be expected if the kaolinite had been produced primarily
during the Paleocene-Eocene thermal maximum. This finding points
to accelerated exhumation and erosion of kaolinitic soils, most
likely Cretaceous laterites.x
Introduction
Results
Discussion
@Timing of clay mineral input at Bass River
@Implications of the oxygen isotope signature of the clay fraction
Conclusions
Acknowledgments
References cited