Our IODP proposal, led by Tom Dunkley-Jones, to drill the Equatorial Atlantic, off the Brazilian Pernambuco Plateau has been successful and is now scheduled to sail in August/September 2020 as IODP Expedition 388 "Equatorial Atlantic Gateway".
This proposal seeks to answer first order questions about the tectonic, climatic and biotic evolution of the Equatorial Atlantic Gateway (EAG). We propose to target sequences of Late Cretaceous and Cenozoic sediments offshore NE Brazil, just south of the theorized final opening point of the EAG.
These sequences are accessible to conventional non-riser drilling in the vicinity of the Pernambuco Plateau, part of the northeastern Brazilian continental shelf. This region was chosen to satisfy two key constraints that other regions in Equatorial Brazil could not meet: first, Aptian-Albian aged sediments, that record the main phases of the South Atlantic marine incursion, are present at depths shallow enough to be recovered by non-riser drilling; second, Late Cretaceous and Paleogene sediments preserved on the Pernambuco Plateau, are close enough to the continental margin, and at shallow enough paleo water depths (<2000 m) to provide well-preserved organic biomarkers and calcareous microfossils for multi-proxy studies of greenhouse climate states. New records in this region will allow us to address major questions within four key themes:
A) The early rift history of the Equatorial Atlantic;
B) Biogeochemistry of the restricted Equatorial Atlantic;
C) The long-term paleoceanography of the Equatorial Atlantic Gateway; and,
D) the limits of tropical climates and ecosystems under conditions of extreme warmth.
Tackling these major questions with new drilling in the EAG region will advance our understanding of the long-term interactions between tectonics, oceanography, ocean biogeochemistry and climate, and the functioning of tropical ecosystems and climate during intervals of extreme warmth.