Middle Ordovician astrochronology decouples asteroid breakup from glacially-induced biotic radiations
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Middle Ordovician astrochronology decouples asteroid breakup from glacially-induced biotic radiations. / Rasmussen, Jan Audun; Thibault, Nicolas; Mac Ørum Rasmussen, Christian.
I: Nature Communications, Bind 12, Nr. 1, 6430, 12.2021.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Middle Ordovician astrochronology decouples asteroid breakup from glacially-induced biotic radiations
AU - Rasmussen, Jan Audun
AU - Thibault, Nicolas
AU - Mac Ørum Rasmussen, Christian
N1 - Publisher Copyright: © 2021, The Author(s).
PY - 2021/12
Y1 - 2021/12
N2 - Meso-Cenozoic evidence suggests links between changes in the expression of orbital changes and millennia-scale climatic- and biotic variations, but proof for such shifts in orbital cyclicity farther back in geological time is lacking. Here, we report a 469-million-year-old Palaeozoic energy transfer from precession to 405 kyr eccentricity cycles that coincides with the start of the Great Ordovician Biodiversification Event (GOBE). Based on an early Middle Ordovician astronomically calibrated cyclostratigraphic framework we find this orbital change to succeed the onset of icehouse conditions by 200,000 years, suggesting a climatic origin. Recently, this icehouse was postulated to be facilitated by extra-terrestrial dust associated with an asteroid breakup. Our timescale, however, shows the meteor bombardment to post-date the icehouse by 800,000 years, instead pausing the GOBE 600,000 years after its initiation. Resolving Milankovitch cyclicity in deep time thus suggests universal orbital control in modulating climate, and maybe even biodiversity accumulation, through geological time.
AB - Meso-Cenozoic evidence suggests links between changes in the expression of orbital changes and millennia-scale climatic- and biotic variations, but proof for such shifts in orbital cyclicity farther back in geological time is lacking. Here, we report a 469-million-year-old Palaeozoic energy transfer from precession to 405 kyr eccentricity cycles that coincides with the start of the Great Ordovician Biodiversification Event (GOBE). Based on an early Middle Ordovician astronomically calibrated cyclostratigraphic framework we find this orbital change to succeed the onset of icehouse conditions by 200,000 years, suggesting a climatic origin. Recently, this icehouse was postulated to be facilitated by extra-terrestrial dust associated with an asteroid breakup. Our timescale, however, shows the meteor bombardment to post-date the icehouse by 800,000 years, instead pausing the GOBE 600,000 years after its initiation. Resolving Milankovitch cyclicity in deep time thus suggests universal orbital control in modulating climate, and maybe even biodiversity accumulation, through geological time.
U2 - 10.1038/s41467-021-26396-4
DO - 10.1038/s41467-021-26396-4
M3 - Journal article
C2 - 34741034
AN - SCOPUS:85118527331
VL - 12
JO - Nature Communications
JF - Nature Communications
SN - 2041-1723
IS - 1
M1 - 6430
ER -
ID: 284773483