Paleodrainage systems and connections to the southern lacustrine belt applying remote sensing data, Amazon coast, Brazil

Abstract

Paleodrainage systems mapped in many regions worldwide reveal important inactive fluvial systems that indicate changes in morphosedimentary, tectonic and environmental processes in different time scales. Two paleodrainage systems were identified north of the Amazon River mouth, associated with the Southern Lacustrine Belt at Cabo Norte. The analyses were performed using data from orbital remote sensors, validated by field information and overflights. The paleodrainage systems show predominant North-South (N-S) and Southwest-Northeast (SW-NE) directions. The N-S system may be connected to an ancient Pleistocene coastline. The SW-NE system is younger, with the same direction as the current river courses and is associated with the genesis of the Araguari River. The paleodrainage alignments of this system in the Northwest-Southeast direction (NW-SE) show the same direction as tectonic lineaments presented from the basement to the continental shelf. The identified paleodrainage systems indicate significant changes in the regional drainage of the Amazonian coastal plain and indicate intense riverbed aggradation processes, which may be associated with neotectonic movements and relative sea level variations during the Quaternary. These are important indicators for the understanding of environmental changes during the Late Pleistocene and Holocene, and may aid in the paleogeographic reconstitution of the Amazon river mouth.