Stratigraphic revision of the Resende Basin, Southeastern Brazil

Abstract

This paper presents a stratigraphic revision of the Tertiary alluvial deposits of the Resende Sedimentary Basin (State of Rio de Janeiro, Southeastern Brazil Continental Rift). Six sedimentary facies associations were recognized and gathered into three stratigraphic units named, from the lower to the upper, Ribeirão dos Quatis Formation, Resende Formation (with its Itatiaia and Acácias members), and Floriano Formation. The Ribeirão dos Quatis Formation is composed by conglomeratic and sandy deposits that represent a sedimentary record previous to the main tectonic episode that originates the basin. Following this unit, the tectonic evolution generated an ENE-WSW half-graben, with alluvial fans along its northern main fault, feeding an axial fluvial system. These alluvial successions correspond to the Resende Formation, representing the main deposits of the basin. The alluvial successions, rich in alkaline rock debris proceeding from the Itatiaia and Morro Redondo massives, were individualized as Itatiaia Member. A newer axial braided fluvial system, characterized by superposition of conglomeratic and arenaceous beds in fining upward cycles, and thick layers of massive pelites, was individualized as Acácias Member. Meandering river deposits related to Floriano Formation represent the Tertiary final filling of the basin.