Source-to-Sink Analysis of the Plio-Pleistocene Deposits in the Suez Rift (Egypt)

Abstract

We present a source-to-sink (S2S) study of the Plio-Pleistocene deposits in the Suez rift (Egypt). We used stratigraphic record and quantitative geomorphology to constrain relief evolution in a rift setting from a high-resolution database at basin-scale (~300 km x 100 km) including, digital elevation model, outcrop and subsurface data. The stratigraphic architecture shows five main stages ranging from rift initiation to tectonic quiescence (Oligo-Miocene) plus a post-rift stage (Plio-Pleistocene). We quantified sediment accumulation history and analysed the relationship between catchment and sediment supply for the Plio-Pleistocene (post-rift stage). The results of the source-tosink study for the post-rift stage were then compared to previous estimations for the main rifting stages.We show that the sediment supply dynamics of the Plio-Pleistocene deposits of the Suez rift records a renewed uplift ca. 5 Myr ago. However, we also show that a major climate shift related to the Pliocene revolution was most probably coeval to reach the magnitude of accumulation observed.

Links Between Faulting, Topography, and Sediment Production During Continental Rifting: Insights From Coupled Surface Process, Thermomechanical Modeling

“…Variations in the associated sediment flux can be related both to tectonic and climatic causes (e.g., Forzoni et al., 2014; McNeill et al., 2019; Rohais & Rouby, 2020; Sømme et al., 2019) and in turn, the preserved stratigraphic record is often used to unravel the effects of tectonic or surface processes, for instance, by inferring the history of rock uplift, the evolution of topography and the drainage network, and climatic variations (e.g., Armitage et al., 2011; Castelltort & Van Den Driessche, 2003; Geurts et al., 2020; Guillocheau et al., 2012; Rohais & Rouby, 2020; Stevens Goddard et al., 2020; Sømme et al., 2019; Whittaker et al., 2010). Correlations between catchment area, runoff, relief, and sediment flux observed in present‐day river systems (Syvitski & Milliman, 2007) are commonly used to invert the evolution of the sediment flux (as preserved in the stratigraphic record), for instance, for the evolution of past relief and catchment area (e.g., Rohais & Rouby, 2020; Sømme et al., 2019). One of the inherent assumptions for this approach is that temporal variations in the sediment flux are coeval and correlated with changes in relief or catchment area also on long timescales a (e.g., as induced by tectonically controlled changes in rock uplift).…”

High‐resolution sedimentary budget quantification – Example from the Cenozoic deposits in the Pelotas Basin, South Atlantic

“…The fourth step is to estimate sediment supply (Qs) (4 in Figure 4), discriminating sediment fluxes entering the basin from catchment erosion and weathering, as well as in-situ sediment production. We refer to previous workflows proposed by Rohais et al (2016) and Rohais and Rouby (2020), who used paleogeographic and lithological maps to calculate the relative proportion of the dominant lithology to finally F I G U R E 6 Thickness maps for the Cenozoic units (I-X) and Cretaceous (undifferentiated) in the Pelotas basin. Contour lines every 500 m, with same colour scale for all the maps.…”

“…We refer to previous workflows proposed by Rohais et al. (2016) and Rohais and Rouby (2020), who used paleogeographic and lithological maps to calculate the relative proportion of the dominant lithology to finally estimate the detrital versus in‐situ sediment production (e.g. carbonate, evaporite).…”

“…8-10 Myr. More recently, Rohais and Rouby (2020) proposed paleogeographic and volumetric lithofacies mapping of 26 depositional units for the Miocene deposit of the Suez rift, that is a mean time step of ca. 0.9 Myr.…”

“…the quantity of solid matter that will be transported from the eroding area in the catchment (Source), through the transfer area, towards the final depositional area in the sedimentary basin (Sink). To understand the variations in relief, the Qs is analysed either through sedimentary budgets in the associated basins (Guillocheau et al., 2012; Jones et al., 2002; Pazzaglia & Brandon, 1996; Pazzaglia & Gardner, 1994; Rohais et al., 2016, 2019; Rohais & Rouby, 2020; Rouby et al., 2009; Rust & Summerfield, 1990; Walford & White, 2005), or using as an analogue the sediment load of modern rivers (Hovius, 1998; Milliman & Syvitski, 1992; Syvitski & Milliman, 2007; Zhang et al., 2018). The estimated Qs is then compared to other methods for estimating the rates of denudation and/or erosion in the catchment areas (e.g.…”