Detection of significant climatic precession variability in early Pleistocene glacial cycles ...

• Main Authors: Liautaud, PR, Hodell, DA, Huybers, PJ
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier BV 2020
• Subjects: Milankovitch; Pleistocene; precession; glacial cycle; spectral analysis; orbital forcing; North Atlantic
• Online Access: https://dx.doi.org/10.17863/cam.49020; https://www.repository.cam.ac.uk/handle/1810/301943

Despite having a large influence on summer insolation, climatic precession is thought to account for little variance in early Pleistocene proxies of ice volume and deep-water temperature. Various mechanisms have been suggested to account for the dearth of precession variability, including meridional insolation gradients, interhemispheric cancellation of ice-volume changes, and antiphasing between the duration and intensity of summer insolation. We employ a method termed Empirical Nonlinear Orbital Fitting (ENOF) to estimate the amplitudes of obliquity and precession forcing in early Pleistocene proxies and their respective leads or lags relative to the timing of orbital variations. Analysis of a high-resolution North Atlantic benthic δ18O record, comprising data from IODP sites U1308 and U1313, indicates a significantly larger precession contribution than previously recognized, with an average precession-to-obliquity amplitude ratio of 0.51 (0.30-0.76 95% confidence interval) in the rate-of-change of δ18O ...