Mechanisms of Climate Warming at the End of the Paleocene

Abstract

An abrupt episode of global warming marked the end of the Paleocene epoch. Oxygen and carbon isotope records from two widely separated sites support the notion that degassing of biogenic methane hydrate may have been an important factor in altering Earth's climate. The data show evidence for multiple injections of methane, separated by intervals in which the carbon cycle was in stasis. Correlations between the two sites suggest that even these small-scale events were global in nature.

The Paleocene–Eocene Thermal Maximum at DSDP Site 277, Campbell Plateau, southern Pacific Ocean

“…1). A similar pattern of warming is evident in the Atlantic Ocean, where the δ 18 O records for ODP sites 690 and 1051 suggest that peak warming occurred at the onset of the PETM in the southern Atlantic (Site 690) but at the same level as the CIE minimum in the western North Atlantic (Bains et al, 1999;Stoll, 2005). We cannot be sure that there was not a second warming pulse above the onset of the PETM on the Campbell Plateau because the main phase of the PETM may not be preserved at Site 277.…”

“…The negative CIE of ∼ 2 ‰ is slightly smaller than the average for marine sections ( 2.7 ‰; McInerney and Wing, 2011) and occurs gradually over the lower 20 cm of the PETM. In contrast, the 3 ‰ negative δ 18 O excursion (OIE) is abrupt at the base of the PETM and is larger in magnitude than is known elsewhere (e.g., Bains et al, 1999;Dunkley Jones et al, 2013). If this is a primary feature and due solely to a change in temperature, this excursion would equate to ∼ 12 • C of warming (Fig.…”

δ13Corgchemostratigraphy of the Permian‐Triassic boundary in the Maitai Group, New Zealand: Evidence for high‐latitudinal methane release

“…Climatic warming associated with the release of gas hydrates has been suggested as the cause of global negative 8 13 C shifts during the latest Paleocene (Dickens et al 1995(Dickens et al , 1997Bains et al 1999), early Eocene (Sloan et al 1992), and mid Cretaceous (Jahren 1998). During the Paleogene, increased slump frequency has been documented during four periods, at the Cretaceous-Tertiary boundary, the PaleoceneEocene boundary, the top of the lower Eocene, and in the middle Eocene (Mountain & Tucholke 1985;Mountain 1987).…”

Origin and fate of deep-sea seeping methane bubbles at Kuroshima Knoll, Ryukyu forearc region, Japan

“…Enormous quantities of carbon occur in marine sediments in seafloor methane hydrates have been suggested as possible causes of sudden climate changes in the geological past (MacDonald, 1990;Dickens et al, 1997;Bains et al, 1999;Svensen et al, 2004). Besides to having environmental significance, seafloor CH 4 bubbles might also be a possible geohazard and have a resource significance (Sills and Wheeler, 1992).…”