Climatically driven Quaternary sedimentation in a passive margin tropical context: Insights into the geomorphological evolution of Northeastern Brazil

Abstract

Unconsolidated regolith from fluvial and hillslope origin occurring along the eastern seaboard of the Northeastern Brazil passive margin has long been overlooked as viable proxy for Quaternary environmental changes, or simply dismissed and interpreted as sediments of older planation cycles, for example, Neogene sediments. This study applies geochemical and geochronological techniques to assess the degree of weathering, sediment provenance and time of residence in the landscape. The results shed light on the upper Quaternary geomorphological history of the Borborema Piedmont, with depositional units spanning the last 50,000 years, as a response to climatic inputs in sync with major Pleistocene events (e.g., Heinrich Event 1, 2, 3 and 5, Last Glacial Maximum) and Holocene events in the Northern Hemisphere (e.g., Holocene Climatic Optimum), and the morphotectonic rearrangement of stream channels base level along reactivated fault-line subordinated to the underlying Proterozoic structural framework.