The Phanerozoic Record of Global Sea-Level Change

TLDR

Sea level records reflect ice‑volume, temperature, and tectonically driven CO₂ variations, and have shaped phytoplankton evolution, ocean chemistry, and sediment burial over the Phanerozoic. The authors review Phanerozoic sea‑level changes from 543 Ma to the present and introduce a new 100‑million‑year record. They analyze sea‑level changes by correlating them with oxygen‑isotope variations across 10⁴‑10⁶‑year scales and attributing 10⁷‑year links to tectonically driven CO₂‑related temperature changes, employing the new record. The study finds that sea level peaked at 100 ± 50 m during the Cretaceous, indicating lower ocean‑crust production rates than previously thought.

Abstract

We review Phanerozoic sea-level changes [543 million years ago (Ma) to the present] on various time scales and present a new sea-level record for the past 100 million years (My). Long-term sea level peaked at 100 +/- 50 meters during the Cretaceous, implying that ocean-crust production rates were much lower than previously inferred. Sea level mirrors oxygen isotope variations, reflecting ice-volume change on the 10(4)- to 10(6)-year scale, but a link between oxygen isotope and sea level on the 10(7)-year scale must be due to temperature changes that we attribute to tectonically controlled carbon dioxide variations. Sea-level change has influenced phytoplankton evolution, ocean chemistry, and the loci of carbonate, organic carbon, and siliciclastic sediment burial. Over the past 100 My, sea-level changes reflect global climate evolution from a time of ephemeral Antarctic ice sheets (100 to 33 Ma), through a time of large ice sheets primarily in Antarctica (33 to 2.5 Ma), to a world with large Antarctic and large, variable Northern Hemisphere ice sheets (2.5 Ma to the present).