Advancing towards an astronomically-calibrated Devonian timescale: Harmonizing cyclostratigraphies between Europe and North America

Astronomical insolation forcing is well established as the underlying metronome of Quaternary ice ages and Cenozoic climate changes. However, its effects on earlier eras (Mesozoic, Paleozoic, and pre-Cambrian) are less understood. In the first part of this presentation, I will argue that formally defining 405,000-year eccentricity cycles as chronostratigraphic units (astrochronozones) throughout the Phanerozoic eon is a crucial research goal for the next decade. Establishing a common cyclostratigraphic framework to harmonize cyclostratigraphies between key sections in Europe and North America (in particular for the Devonian) is of primary importance. The goal of defining Phanerozoic astrochronozones would enhance our understanding of how astronomical forcing has shaped Earth's climate over geologic time.

Subsequently, I will discuss several lines of evidence suggesting that Devonian oxygen deficiency was sensitive to rhythmic astronomical forcing. Nonetheless, the question of why some anoxic events were more severe than others remains unresolved. Therefore, it is increasingly important to employ cyclostratigraphy to distinguish between different climate modes of the Devonian and to improve our understanding of the role of astronomical forcing in Devonian ocean anoxic events.