A Fulcrum Approach To Assessing Source-To-Sink Mass Balance Using Channel Paleohydrologic Paramaters Derivable From Common Fluvial Data Sets With An Example From the Cretaceous of Egypt

Extremes in dune preservation: Controls on the completeness of fluvial deposits

“…Lunt et al, 2004Lunt et al, , 2013Gibling, 2006;Fielding, 2007;Sambrook Smith et al, 2009), even though alternative models for the interpretation of formative bedform heights are available (Rubin and Hunter, 1982;Kleinhans, 2001Kleinhans, , 2002Blom and Kleinhans, 2008;Reesink and Bridge, 2007;Reesink et al, 2014b). However, the existence of form-sets, and systematic applications of the variability-dominated model, indicate that this model is not universally applicable (Jerolmack and Mohrig, 2005;Leclair, 2011;Holbrook and Wanas, 2014). Importantly, the use of a channel-wide average value to represent vertical aggradation (Bridge, 1997) inherently assumes internal homogeneity within the channel.…”

“…Thus, near-horizontal beds in the sedimentary record may represent a temporally selective subset of the total of all flow conditions. The pdfs of set thicknesses that related to deposits of the thalweg are indeed known to differ from the overlying dune sets (Holbrook and Wanas, 2014), although the relative roles of different controlling factors that affect dune size and scour in the thalweg, such as supply limitation, secondary flow, and stage variability, require further systematic research. The pdf of scour distributions is modified differently in cases where dunes migrate into an area of flow deceleration.…”

“…However, systematic application of this 'variability-dominated' model typically indicates that this model of dune preservation is not universally applicable (e.g. Jerolmack and Mohrig, 2005;Leclair, 2011;Reesink and Bridge, 2011;Holbrook and Wanas, 2014). Consequently, the stratigraphic completeness of fluvial deposits remains inadequately understood, and the accuracy of paleoenvironmental interpretations that use preserved dune sets may require modification.…”

Empirical relationship between river slope and the elongation of bars in braided rivers: a potential tool for paleoslope analysis from subsurface data

“…Clearly, the identification of bars is not unambiguous, but it here only serves for the purpose of illustration. The analysis of all the bars (N=29) shown on the stratal-slice of figure With data on channel depth and width, such paleoslope estimate can be used to reconstruct water discharge during channel-forming events and associated paleo-precipitation, which can be useful to infer climatic regimes and be integrated into more general facies models to inform predictions of sediment supply, reservoir properties, upstream/downstream trends in stratigraphic architecture and mass balance approaches (e.g., the fulcrum approach of Holbrook and Wanas, 2014). In the present case study, the obtained paleoslope constraints are plotted on a global database of slope and median grain-size ( !"…”

“…Paleoslope is a parameter of fundamental importance for reconstructing paleohydrology, paleoclimate and tectonics from the fluvial archives (Paola and Mohrig, 1996, Duller et al, 2012, Holbrook and Wanas, 2014, understand the controls on aggradation, degradation and signal transmission in fluvial systems Van Den Driessche, 2003, Romans et al, 2016), and predict grain size and reservoir properties in hydrocarbon exploration and water-resource management (e.g., Bhattacharya and Tye, 2004). Braided rivers consist of multiple channels characterized by fundamental morphological units made of channel confluences-bifurcations separating pool-bars visible at median and low water stage (Ferguson, 1993, Ethridge and Schumm, 2007, Hundey and Ashmore, 2009 Castelltort and Yamato (2013).…”