Integrating geologic and SRTM data to identify geomorphologic landforms in the Eastern Amazon River Valley

Geography and the Environment

Studies of the Amazon drainage network have primarily focused on the Western Basin and the Amazon Cone, but they have neglected the integration between these areas. Data presents a time gap in the Amazon’s development and the forces responsible for the organization of the drainage network are poorly understood. A key element towards gaining an improved awareness of the Amazon is the Eastern Amazon River Valley. The focus of this study is an 80,000 km² portion of this area. An integrated method is adopted that combines terrain information derived from a digital elevation model with geologic data. The interpretation of DEM data is unique to this study. Seven distinct surfaces were identified, along with numerous erosional environments. This observation supports a geomorphologic record of numerous erosional events starting in the Miocene. This finding is significant as it rejects previous models for staircase-like terraces for the Amazon, and establishes a timeline for the development of geomorphologic landforms in the study area. In addition, neotectonics events provide an alternative explanation to the generation of topography in the study area. It was concluded that geomorphology in the study area is the result of physical and chemical weathering, and modified by neotectonics. These findings provide alternative means for Amazon landscape evolution.