Atmospheric oxygenation driven by unsteady growth of the continental sedimentary reservoir

Abstract

Atmospheric oxygen concentration has increased over Earth history, from ∼0 before 2.5 billion years ago to its present-day concentration of 21%. The initial rise in pO 2 approximately 2.3 billion years ago required oxygenic photosynthesis, but the evolution of this key metabolic pathway was not sufficient to propel atmospheric oxygen to modern levels, which were not sustained until approximately two billion years later. The protracted lag between the origin of oxygenic photosynthesis and abundant O 2 in the surface environment has many implications for the evolution of animals, but the reasons for the delay remain unknown. Here we show that the history of sediment accumulation on continental crust covaries with the history of atmospheric oxygen concentration. A forward model based on the empirical record of net organic carbon burial and oxidative weathering of the crust predicts two significant rises in pO 2 separated by three comparatively stable plateaus, a pattern that reproduces major biological transitions and proxy-based pO 2 records. These results suggest that the two-phased oxygenation of Earth's surface environment, and the long delays between the origin of life, the evolution of metazoans, and their subsequent diversification during the Cambrian Explosion, were caused by step-wise shifts in the ability of the continents to accumulate and store sedimentary organic carbon. The geodynamic mechanisms that promote and inhibit sediment accumulation on continental crust have, therefore, exerted a first-order control on the evolution of Earth's life and environment.

Macrostrat: a platform for geological data integration and deep-time Earth crust research

“…2). Although evidence suggests that there is indeed a global expression of the Great Unconformity 16,74 , testing this hypothesis requires geographic expansion of column coverage. We hope that this objective will be facilitated by engaging geoscientists with regional expertise and leveraging their in-hand knowledge.…”

“…Determining whether this strong signal of increased sediment quantity on the continents is North America-specific or a global phenomenon is critical to addressing many fundamental questions about the evolution of Earth and life 16 . A current major limitation of Macrostrat is the geographically restricted nature of its surface-subsurface data (i.e., columns).…”

“…11) shifted emphasis away from Ronov's laborious approach of compiling data on the rock record and towards the production of new geochemical proxy records, some of which could be extracted with more efficiency and with much higher temporal resolution in one or more well correlated stratigraphic sections. Nevertheless, many of the models used to interpret geochemical proxy records require that assumptions be made about burial and weathering fluxes, assumptions that are difficult to assess without independent data on the rock record [12][13][14][15][16] . When interrogating Earth history, there thus remains a great need for spatially and temporally complete quantitative descriptions of the rock record that can be combined with geochemical models.…”

Plate tectonic regulation of global marine animal diversity

“…The Macrostrat database records the lithologic, environmental, spatial, and temporal attributes of geologic units derived from published stratigraphic columns (26,61,62). Although some data are global in scope, Macrostrat's coverage is complete only for North America.…”

Macrostrat: A Platform for Geological Data Integration and Deep‐Time Earth Crust Research

“…The subsequent emergence of isotope‐based approaches to deciphering changes in Earth systems (e.g., Des Marais et al, ) shifted emphasis away from Ronov's laborious approach of compiling data on the rock record and toward the production of new geochemical proxy records, which could be extracted with more efficiency and with higher temporal resolution in one or more well‐correlated stratigraphic sections. Nevertheless, most of the models that are used to interpret geochemical proxy records require that assumptions be made about burial and weathering fluxes, which are difficult to assess without independent data on the rock record (Bergman et al, ; Berner & Kothavala, ; Halevy et al, ; Husson & Peters, ; Schrag et al, ). Thus, there remains a need for spatially and temporally complete quantitative descriptions of the rock record that can be combined with geochemical models and other proxy records.…”