2026-10-15T13:30:56Z https://oai.datacite.org/oai

doi:10.1594/pangaea.741863 2024-08-16T05:32:43Z PANGAEA PANGAEA.REPOSITORY

Isotope measurements from late Paleocene - early Eocene of 5 cores from Atlantic and Pacific Ocean Cramer, Benjamin S Wright, James D Kent, Dennis V Aubry, Marie-Pierre PANGAEA 2003 Issued: 2003 doi:10.1029/2003pa000909 Drilling/drill rig Leg80 Leg86 Leg113 Leg171B Glomar Challenger Joides Resolution Deep Sea Drilling Project (DSDP) Ocean Drilling Program (ODP) High-resolution stable carbon isotope records for upper Paleocene - lower Eocene sections at Ocean Drilling Program Sites 1051 and 690 and Deep Sea Drilling Project Sites 550 and 577 show numerous rapid (40 - 60 kyr duration) negative excursions of up to 1 per mill. We demonstrate that these transient decreases are the expected result of nonlinear insolation forcing of the carbon cycle in the context of a long carbon residence time. The transients occur at maxima in Earth's orbital eccentricity, which result in high-amplitude variations in insolation due to forcing by climatic precession. The construction of accurate orbital chronologies for geologic sections older than ~ 35 Ma relies on identifying a high-fidelity recorder of variations in Earth's orbital eccentricity. We use the carbon isotope records as such a recorder, establishing a robust orbitally tuned chronology for latest Paleocene-earliest Eocene events. Moreover, the transient decreases provide a means of precise correlation among the four sites that is independent of magnetostratigraphic and biostratigraphic data at the <10^5-year scale. While the eccentricity-controlled transient decreases bear some resemblance to the much larger-amplitude carbon isotope excursion (CIE) that marks the Paleocene/Eocene boundary, the latter event is found to occur near a minimum in the ~400-kyr eccentricity cycle. Thus the CIE occurred during a time of minimal variability in insolation, the dominant mechanism for forcing climate change on 104-year scales. We argue that this is inconsistent with mechanisms that rely on a threshold climate event to trigger the Paleocene/Eocene thermal maximum since any threshold would more likely be crossed during a period of high-amplitude climate variations. Supplement to: Cramer, Benjamin S; Wright, James D; Kent, Dennis V; Aubry, Marie-Pierre (2003): Orbital climate forcing of d13C excursions in the late Paleocene-early Eocene (chrons C24n–C25n). Paleoceanography, 18(4), 1097 en Collection Supplementary Publication Series of Datasets application/zip Creative Commons Attribution 3.0 Unported https://creativecommons.org/licenses/by/3.0/legalcode