Uplift evolution along the Red Sea continental rift margin from stream profile inverse modeling and drainage analysis

Abstract

Continental rifted margins can have complex uplift histories related to different processes including footwall uplift by mechanical unloading, dynamic uplift and interaction with transfer margins. Deciphering uplift histories along rift flanks is integral to understanding the margin evolution as a whole. Here, a combination of drainage analysis and stream profile inverse modeling is utilized to estimate the rift flank uplift along the north-eastern Red Sea onshore margin. The drainage network was extracted from an ASTER DEM (∼30 x 30 m-horizontal resolution) and the uplift history was calculated using an inverse model, which builds on the relationship between uplift, erosion and stream profile shape. Local relief, minimum erosion volumes and minimum erosion volume:catchment area ratios (Rva) were also calculated and compared to uplift estimates. Within the study area, small catchments represent footwall drainage and larger catchments are mostly associated with pre-rift structures and syn-rift accommodation zones. Uplift initiated in the southern part during early rifting (21-15 Ma) before shifting northward (12-0 Ma). This uplift distribution is reflected in Rva and relief maps. Early-rift uplift is interpreted as a record of early-rift faulting with possible additional mantle support, whereas later uplift was driven by fault linkage and mantle upwelling (12-6 Ma) as well as transform tectonics (6-0 Ma). These modeling results are largely in agreement with other independent data (low-temperature thermochronology and dated carbonate terraces). Our workflow benefits from its utilization of ubiquitous drainage data. The combination of drainage analysis and inverse modeling proves to be more discerning than either one method in isolation, and may have application to analysis of other margins.