Incision Mapping of a Drainage Basin from Integrated GIS and Digital Elevation Models: Implications for Sediment Budget and Timing in Frontier Petroleum Basins

Gani, Nahid DS¹ (1) University of Utah, Salt Lake City, UT

Remote sensing based Geographic Information System (GIS) analysis has proved to be a powerful tool for large-scale incision mapping. Such an approach is undertaken to study the ~1.6 km deep incision of the Blue Nile drainage basin into the Ethiopian Plateau. GIS analysis of 90 meters resolution Shuttle Radar Topography Mission (SRTM) Digital Elevation Models (DEMs) has been used for quantifying depth, rate, timing, as well as spatial variation and geologic factors controlling incision on the uplifted Plateau. In addition, isotopic, geochronological, and paleontological data of Cenozoic rocks exposed by the Blue Nile drainage system are used to reveal the changes of incision rates through geologic time. A three-phase incision history is proposed for the Blue Nile drainage starting at ~30 Ma ago with a total incision of 1.6 km and an abrupt increase in the incision rate around 10 Ma and 6 Ma. Similar techniques of erosion/incision analysis can be used for any continental and isolated submarine drainage systems using high resolution (5-10 meters) DEMs and bathymetric data, respectively. The erosion map can be used to calculate input sediment volume distributed down the basin in alluvial fan, delta, and/or submarine fan. The timing of differential erosion can be crucial in understanding sediment partitioning and evolution of various depositional systems. These techniques can be critical to understand the timing and distribution of source, reservoir, and seals in potential petroleum provinces, particularly in frontier basins.