Long-term vegetation-induced goethite and hematite dissolution-reprecipitation along the Brazilian Atlantic margin

Distinctive sediments containing mostly quartz, kaolinite, and both detrital authigenic hematite goethite blanket ~5000 km of the Atlantic coast Brazil from Rio de Janeiro all way to mouth Amazon River. The represent a significant period continental erosion followed by renewed weathering. Here we present (UTh)/He ages goethites hematites collected six weathering profiles in Espírito Santo, southeastern Brazil. Detrital are as old ~26 Ma oldest is ~20 Ma, suggesting that erosion, transportation, deposition occurred 26–20 period. Intense post-depositional ferruginization suggest precipitation-dissolution-reprecipitation iron oxides oxyhydroxides were strongly controlled biologically driven reactions. geochronology 158 grains precipitated during mediated water-rock interaction yield 137 results 5–0.6 period, tropical climate abundant vegetation dominated Santo since Pliocene.