Comments: (pdf)
Ref.: Minerals16, 418, April 2026
Abstract:
The Rio Grande Rise (RGR) is the largest oceanic plateau in the South Atlantic and represents
a key natural laboratory for understanding oceanic plateau formation, deep-sea
circulation, ecosystem functioning, and ferromanganese crust development. This study
presents a critical synthesis of current scientific knowledge on the RGR, integrating geological,
geophysical, oceanographic, biological, and geochemical evidence published over the
last two decades. Geophysical data reveal a complex tectono-magmatic evolution involving
Late Cretaceous plume-related volcanism, crustal thickening, rifting, and subsequent
subsidence. The structural framework of the plateau is dominated by the Cruzeiro do Sul
Rift, which plays a central role in controlling sedimentation, magmatism, and seawater
circulation. Oceanographic studies demonstrate that the interaction between the southern
branch of the South Equatorial Current and the complex topography of the RGR generates
intense internal tides and bottom currents, strongly influencing sediment transport and
benthic habitats. Biological investigations indicate that the RGR hosts diverse deep-sea
communities, including sponge grounds, cold-water corals, and associated fauna, whose
distribution is tightly linked to geomorphology and hydrodynamics. Ferromanganese
crusts occurring on the plateau preserve valuable geochemical records of oceanographic
and redox conditions, although their spatial distribution, thickness, and metal budgets
remain incompletely constrained. Despite major advances, significant knowledge gaps
persist regarding crustal structure, sedimentary evolution, ecosystem functioning, and
mineral formation processes. This review highlights these uncertainties and outlines research
priorities necessary to improve understanding of oceanic plateaus and deep-sea systems in
the South Atlantic.