Clay assemblage and oxygen isotopic constraints on the weathering response to the Paleocene-Eocene thermal maximum, east coast of North America

Abstract

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 yearround 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 δ 18 O of the <2-µm-size fraction exhibits a shift toward lower values during the event. On the basis of a coeval shift in clay assemblages, the shift in δ 18 O Clays 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 fi nding points to accelerated exhumation and erosion of kaolinitic soils, most likely Cretaceous laterites.

Paleocene–Eocene Thermal Maximum environmental change in the New Jersey Coastal Plain: benthic foraminiferal biotic events

“…related to global warming during the PETM, and include an intensified hydrologic cycle with variable seasonal precipitation patterns (intense wet season and prolonged dry season), and accelerated hinterland erosion of exposed kaolinite-rich Cretaceous deposits (Kopp et al, 2009;John et al, 2012). Intensified erosion resulted in increasing sediment loads in the rivers, supplying large amounts of suspended clay (Gibson et al, 1993;Zachos et al, 2006;Kopp et al, 2009), and leading to enhanced sediment accumulation rates at all sites.…”

“…Limited precursor events occurred prior to the PETM, such as the start of the Apectodinium bloom and a higher Spiniferites-Areoligera ratio (Sluijs and Brinkhuis, 2009), rising surface water temperatures (Sluijs et al, 2007b), increased accumulation rates and declining grain-size at Wilson Lake (Stassen et al, 2012c) and increased kaolinite input (John et al, 2012). These pre-PETM environmental changes are corroborated by the increasing %P and diversity from WL 110.47 m and BR 357.71 m onwards, starting 40 to 45 kyr prior to the main environmental changes (Fig.…”

Climate‐driven generation of a fluvial sheet sand body at the Paleocene–Eocene boundary in north‐west Wyoming (USA)

“…Increases in fire frequency during the PETM, as witnessed in other locations (Collinson et al, 2007), may have also contributed to formation of the Boundary Sandstone by clearing the landscape of vegetation and accelerating lateral mobility. Finally, the Boundary Sandstone adds to a growing appreciation for anomalous sedimentation events at the Paleocene-Eocene Boundary both in terrestrial (Schmitz & Pujalte, 2007;Fricke et al, 2011;Foreman et al, 2012) and marine settings (Robert & Kennett, 1994;Bolle & Adatte, 2001;Pagani et al, 2006John et al, 2012. Finally, the Boundary Sandstone adds to a growing appreciation for anomalous sedimentation events at the Paleocene-Eocene Boundary both in terrestrial (Schmitz & Pujalte, 2007;Fricke et al, 2011;Foreman et al, 2012) and marine settings (Robert & Kennett, 1994;Bolle & Adatte, 2001;Pagani et al, 2006John et al, 2012.…”

Volume 364: Chicxulub: Drilling the K-Pg Impact Crater

“…There was an intensified hydrological cycle and warming across the PETM (Zachos et al, 2001), and inputs of kaolinite, illite, palygorskite, and/or sepiolite, as well as major elements related to silicate weathering (Schulte et al, 2011) into sedimentary basins during this period, have been linked to an increase in runoff (John et al, 2012). Suevite, impact melt rock, and basement rocks forming the peak ring…”