Geochemistry of the alkaline volcanicsubvolcanic rocks of the Fernando de Noronha Archipelago, southern Atlantic Ocean

The Fernando de Noronha Archipelago exhibits two distinct volcanic units separated by a significant time gap and erosion surface. The older Remédios Formation (8–12 million years ago) consists of alkaline rocks with both sodic and potassic sequences, showing continuous geochemical trends indicative of crystal fractionation, while the younger Quixaba Formation (1–3 million years ago) comprises primitive, undersaturated sodic rocks. Geological, stratigraphic, petrographic, and geochemical evidence suggests these islands originated from intermittent melting of an enriched mantle, unrelated to asthenospheric plume activity. This study deciphers the archipelago's volcanic evolution through detailed petrological and geochemical analysis.

Lopes, R. P., & Ulbrich, M. N. C. (2015). Geochemistry of the alkaline volcanicsubvolcanic rocks of the Fernando de Noronha Archipelago, southern Atlantic Ocean. Brazilian Journal of Geology, 45(2), 307–333. https://doi.org/10.1590/23174889201500020009