Synchroneity of major Late Neogene sea level fluctuations and paleoceanographically controlled changes as recorded by two carbonate platforms

Abstract

Shallow‐water carbonate systems are reliable recorders of sea level fluctuations and changes in ambient seawater conditions. Drilling results from Ocean Drilling Program (ODP) Legs 133 and 166 indicate that the timing of late Neogene sedimentary breaks triggered by sea level lowerings is synchronous in the sedimentary successions of the Queensland Plateau and the Great Bahama Bank. This synchrony indicates that these sea level changes were eustatic in origin. The carbonate platforms were also affected by contemporary, paleoceanographically controlled fluctuations in carbonate production. Paleoceanographic changes are recorded at 10.7, 3.6, and 1.7–2.0 Ma. At the Queensland Plateau, sea surface temperature shifts are documented by shifts from tropical to temperate carbonates (10.7 Ma) and vice versa (3.6 Ma); the modern tropical platform was established at 2.0–1.8 Ma. At Great Bahama Bank, changes were registered in compositional variations of platform‐derived sediment, such as major occurrence of peloids (3.6 Ma) and higher rates of neritic carbonate input (1.7 Ma). The synchroneity of these changes attests to the far‐field effects of modifications in the oceanographic circulation on shallow‐water, low‐latitude carbonate production.