A Jurassic record encodes an analogous Dansgaard\u2013Oeschger climate periodicity

Slah Boulila,Pierre Pellenard,Silvia Gardin,Bruno Galbrun

doi:10.1038/s41598-022-05716-8

Abstract

Earth’s past climate exhibits short-term (1500-year) pronounced fluctuations during the last glacial period, called Dansgaard–Oeschger (DO) glacial events, which have never been detected in pre-Quaternary times. The record of DO equivalent climate variability in Mesozoic strata can provide constraints on understanding these events. Here we highlight a prominent 1500-year cyclicity in a Jurassic (~ 155 Ma) ice-free sedimentary record from the Tethyan Basin. This Jurassic 1500-year cyclicity is encoded in high-resolution magnetic susceptibility (MS) proxy data reflecting detrital variations, and expressed as marl-limestone couplets. Additionally, MS data detect the modulation of these DO-scale couplets by supercouplet sets, reflecting the precession and its harmonics. We suggest that this Jurassic DO-like cyclicity may originate from paleo-monsoon-like system, analogous to the record of DO events in the Pleistocene East Asian monsoon archives. Paleogeographic reconstructions and atmosphere–ocean simulations further support the potential existence of strong, ancient monsoon circulations in the Tethyan Basin during the Jurassic.

Highlights

Earth’s past climate exhibits short-term (1500-year) pronounced fluctuations during the last glacial period, called Dansgaard–Oeschger (DO) glacial events, which have never been detected in preQuaternary times
Amplitude modulation (AM) analysis of these two close cyclicities indicates that they are strongly modulated by the precession and its harmonics (Fig. 4 and Supplementary figures S2-S7)
Field observation reveals a striking modulation of the elementary marl-limestone couplets by supercouplet sets matching especially the precession and its first harmonic (Supplementary figures S2-S5)

Summary

Introduction

Earth’s past climate exhibits short-term (1500-year) pronounced fluctuations during the last glacial period, called Dansgaard–Oeschger (DO) glacial events, which have never been detected in preQuaternary times. We highlight a prominent 1500-year cyclicity in a Jurassic (~ 155 Ma) ice-free sedimentary record from the Tethyan Basin. MS data detect the modulation of these DO-scale couplets by supercouplet sets, reflecting the precession and its harmonics We suggest that this Jurassic DO-like cyclicity may originate from paleo-monsoon-like system, analogous to the record of DO events in the Pleistocene East Asian monsoon archives. Earth’s past climate exhibits a prominent millennial-scale quasi-cyclic (period of about 1500 years) variability, the origin of which is intensively debated. Such cyclicity, known as the Dansgaard–Oeschger (DO) glacial variations, is characterized by brief, decadal-scale shifts from stadial cold to interstadial warm climates, called the DO events, followed by slow transitions back to stadials within centuries to millennia[1]. CNRS‐UMR8028, Observatoire de Paris, PSL University, Sorbonne Université, 77 Avenue Denfert‐Rochereau, 75014 Paris, France. 3MNHN, CNRS, Centre de Recherche Sur La Paléobiodiversité Et Les Paléoenvironnements, CR2P, Sorbonne Université, 75005 Paris, France. 4UMR 6282, uB/CNRS, Université Bourgogne Franche-Comté, 6

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