Interpretation of cross strata formed by unit bars

The anatomy of exhumed river‐channel belts: Bedform to belt‐scale river kinematics of the Ruby Ranch Member, Cretaceous Cedar Mountain Formation, Utah, USA

“…As such, this bounding surface preserves the characteristic dip of the stoss side of the bar form. The bar‐lee strata may be compound in that they are composed of dune cross‐sets, or bar slip faces, which may nonetheless be influenced by superimposed dunes and ripples (Reesink & Bridge, 2011; Reesink, 2018). Theory (Paola & Borgman, 1991) and a recent morphodynamic bedform model (Swanson et al , 2019) show that set stacking can occur even under conditions of net bypass or erosion because of variability in dune scour depths.…”

“…In plan‐view exposures, the net migration direction can be determined reliably, as well as the orientation of the bar surface the dune migrated on (Dott, 1973; Almeida et al , 2016). In channel deposits, larger dipping strata composed of smaller dune cross‐sets, called compound strata, represent the accretion surfaces of barforms built by superimposed dunes (Allen, 1983; Haszeldine, 1983; Edwards et al , 1983; Miall, 1985, 1988; Almeida et al , 2016; Reesink, 2018).…”

The Influence of Transport Stage on Preserved Fluvial Cross Strata

“…However, extracting this information requires the analysis of multiple hierarchical elements within the fluvial morphodynamic hierarchy (Ganti et al., 2020). The formative flow depths can be independently constrained from preserved bar clinoforms (e.g., Reesink, 2019; Mohrig et al., 2000), thus, enabling field estimation of $$\left\langle \overline{{D}_{\mathrm{s}\mathrm{t}}}\right\rangle /h$$ , whilst transport stage can be assessed from geometry and sorting of dune cross strata (Reesink and Bridge, 2009; Kleinhans, 2004). Trends in $$\left\langle \overline{{D}_{\mathrm{s}\mathrm{t}}}\right\rangle /h$$ can then be used to quantify formative transport stages, where a lower $$\left\langle \overline{{D}_{\mathrm{s}\mathrm{t}}}\right\rangle /h$$ value is expected for deposits corresponding to suspension‐dominated conditions (peak flood) when compared to deposits constructed under bedload‐dominated and lower‐mixed load conditions (rising and falling limb of hydrograph).…”

Palaeohydrological characteristics and palaeogeographic reconstructions of incised‐valley‐fill systems: Insights from the Namurian successions of the United Kingdom and Ireland

“…8). Misidentification of cross‐sets that represent the preserved product of unit bars (Reesink, 2019) or of bedforms that developed under conditions of upper flow‐regime or at the transition to the upper flow‐regime, as dunes, is another possible explanation. Furthermore, the scaling between dune height and flow depth is influenced by flow regime, controlling where dunes sit on the bedform stability field, and determining an increase in height from the transition from ripple or lower‐stage plane beds to a maximum in the middle of the dune field, followed by a decrease to near zero at the transition to the upper‐stage plane beds (Bridge & Tye, 2000).…”