A Chronology of Paleozoic Sea-Level Changes

TLDR

Sea levels have been measured across most of the Paleozoic, yet a comprehensive, integrated history has remained unrealized. The authors reconstructed the entire Paleozoic sea‑level record by compiling stratigraphic sections from pericratonic and cratonic basins. They identified 172 eustatic events ranging from a few tens of meters to about 125 m, revealing a gradual rise to a Late Ordovician high, a sharp Hirnantian glacial low, and subsequent smaller highs and lows through the Silurian to Late Permian, while noting that accurately estimating event magnitudes is the most problematic aspect.

Abstract

Sea levels have been determined for most of the Paleozoic Era (542 to 251 million years ago), but an integrated history of sea levels has remained unrealized. We reconstructed a history of sea-level fluctuations for the entire Paleozoic by using stratigraphic sections from pericratonic and cratonic basins. Evaluation of the timing and amplitude of individual sea-level events reveals that the magnitude of change is the most problematic to estimate accurately. The long-term sea level shows a gradual rise through the Cambrian, reaching a zenith in the Late Ordovician, then a short-lived but prominent withdrawal in response to Hirnantian glaciation. Subsequent but decreasingly substantial eustatic highs occurred in the mid-Silurian, near the Middle/Late Devonian boundary, and in the latest Carboniferous. Eustatic lows are recorded in the early Devonian, near the Mississippian/Pennsylvanian boundary, and in the Late Permian. One hundred and seventy-two eustatic events are documented for the Paleozoic, varying in magnitude from a few tens of meters to approximately 125 meters.