264-10 Reconstructing Seawater Carbonate Saturation Through Time

Abstract:

One of Brad Sageman’s enduring scientific contributions has been to illuminate the processes that regulate carbon burial and the feedbacks by which they shape Earth’s climate and ocean chemistry. Together with organic carbon burial, the formation and burial of marine carbonates constitute the other principal pathway by which carbon is transferred from the ocean-atmosphere system to the solid Earth. Central to this process is the carbonate saturation state, which governs the rate and magnitude of carbonate precipitation, and the evolution of the marine carbonate factory, thereby influencing marine biogeochemical cycling, atmospheric CO₂, and climate. Yet despite its fundamental importance, the scarcity of empirical constraints on the magnitude and tempo of secular changes in carbonate saturation has led to divergent views of how seawater carbonate chemistry has evolved through Earth history. In this talk, using minimal widely accepted assumptions together with observational constraints, we present a new numerical framework for reconstructing secular variations in seawater carbonate saturation through geological time. Our results provide testable constraints on the evolution of seawater carbonate saturation, and offer a complementary perspective on the long-term co-evolution of carbon burial, Earth’s surface environment, and life.

Geological Society of America Abstracts with Programs. Vol. 58, No. 5, 2026

doi: 10.1130/abs/2026AM-19225

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