Understanding Amazonian fluvial rias based on a Late Pleistocene–Holocene analog

摘要: Fluvial rias are elongated lakes at tributary mouths that can reach dozens of kilometers in length, constituting one the most remarkable features Amazonian landscape. Thus far, definitive data which documents genesis fluvial have not been published. The main goal this work was to integrate morphological, sedimentological and chronological information order characterize paleorias interfluve Purus Madeira Rivers discuss likely hypothesis for their genesis. These were first observed through remote sensing imagery as several interconnecting belts open vegetation sharp contact with surrounding dense forest. branched form a dendritic pattern similar many modern drainage networks. sedimentary record these revealed prevalence sharp-based sandstones mudstones arranged into fining-upward successions, compatible deposition within channels. Active channel abandoned deposits recognized. topped by continuous related rapid abandonment formation low energy basin or ria environment. Radiocarbon dating recorded only Late Pleistocene Holocene ages ranging from 21 547–22 285 cal yr bp 5928–6124 cal yr bp. This chronology sediment is being formed erosion during Last Glaciation Maximum sea level, accumulation subsequent transgression. Instead, studied previous tributaries River became position river shifted southeastward its tilted northward, inverting systems. Therefore, neotectonic origin some seems likely. should be considered further investigations aiming understanding numerous typify Copyright © 2014 John Wiley & Sons, Ltd.