Marine Ooid Sizes Record Phanerozoic Seawater Carbonate Chemistry
Abstract
Seawater carbonate chemistry links Earth's climate and carbon cycle through the production and preservation of carbonate sediments. Models and carbonate facies abundance records have generated hypotheses about trajectories of seawater carbonate chemistry, including responses to key events in the evolutionary history of carbonate biomineralizers. However, tests of these hypotheses have remained elusive. We applied a novel proxy for the carbonate mineral saturation state (Ω) of seawater based on the diameters of ooids—concentrically-coated carbonate sand grains—to estimate Ω, dissolved inorganic carbon, alkalinity, and pH of seawater spanning Phanerozoic time. Reconstructed Ω values decreased sharply around ∼120 Ma, which we interpret as the fingerprint of the Mid-Mesozoic Revolution of planktic calcifiers. Shifts in Ω across Ordovician time also suggest a possible causal relationship with the Great Ordovician Biodiversification Event. Our results demonstrate that ooid sizes are a useful tool for reconstructing Earth's ancient carbon cycle.
Additional Information
The authors thank Shaily Rahman, Rowan Martindale, Benjamin Barnes, and Giovanni Aloisi for helpful discussion. The authors declare no funding sources.Additional details
- Eprint ID
- 118494
- Resolver ID
- CaltechAUTHORS:20221219-417430800.20
- Created
-
2023-01-20Created from EPrint's datestamp field
- Updated
-
2023-01-22Created from EPrint's last_modified field