Decimeter‐scale in situ mapping of modern cross‐bedded dune deposits using parametric echo sounding: A new method for linking river processes and their deposits

Collecting high‐resolution data to quantify the sedimentary architecture within contemporary alluvial channels remains one of the outstanding challenges in fluvial sedimentology. Here, we present data collected using a new geophysical method, the parametric echo sounder (PES), which can meet this challenge. From surveys over a field of sand dunes in the Río Paraná, Argentina, we demonstrate the unique ability of PES to image the subsurface structure within active channels at a decimetric resolution. These data reveal the bounding surfaces between bars and dunes, as well as the foresets and reactivation surfaces within them. This provides quantitative in situ data for recent work that suggests cross‐strata preserved by dunes may be more related to flow depths less than the commonly assumed bankfull level. These surveys demonstrate that PES can provide hitherto unobtainable data from alluvial channels and presents significant opportunities for more detailed coupled studies of fluvial processes and their deposits.

[1]  Greg . Smith,et al.  Deposits of the sandy braided South Saskatchewan River: Implications for the use of modern analogs in reconstructing channel dimensions in reservoir characterization , 2013 .

[2]  P. Heller,et al.  Flow-Depth Scaling in Alluvial Architecture and Nonmarine Sequence Stratigraphy: Example from the Castlegate Sandstone, Central Utah, U.S.A. , 2012 .

[3]  S. Leclair Interpreting Fluvial Hydromorphology from the Rock Record: Large-River Peak Flows Leave No Clear Signature , 2011 .

[4]  T. Garlan,et al.  Migration and internal architecture of marine dunes in the eastern English Channel over 14 and 56 year intervals: the influence of tides and decennial storms , 2010 .

[5]  J. Bridge,et al.  Influence of bedform superimposition and flow unsteadiness on the formation of cross strata in dunes and unit bars — Part 2, further experiments , 2009 .

[6]  Greg . Smith,et al.  The Sedimentology and Alluvial Architecture of a Large Braid Bar, Rio Parana, Argentina , 2009 .

[7]  J. Alexander,et al.  Sedimentary facies from ground-penetrating radar surveys of the modern, upper Burdekin River of north Queensland, Australia: Consequences of extreme discharge fluctuations , 2009 .

[8]  S. Lane,et al.  Causes of rapid mixing at a junction of two large rivers: Río Paraná and Río Paraguay, Argentina , 2008 .

[9]  J. Best,et al.  The Brahmaputra-Jamuna River, Bangladesh , 2008 .

[10]  J. Bridge,et al.  Influence of superimposed bedforms and flow unsteadiness on formation of cross strata in dunes and unit bars , 2007 .

[11]  W. Kean,et al.  Architecture and sedimentology of an active braid bar in the Wisconsin River based on 3-D ground penetrating radar , 2007 .

[12]  A. Miall Reconstructing the architecture and sequence stratigraphy of the preserved fluvial record as a tool for reservoir development: A reality check , 2006 .

[13]  P. Ashworth,et al.  The sedimentology and alluvial architecture of the sandy braided South Saskatchewan River, Canada , 2006 .

[14]  J. Best The fluid dynamics of river dunes: A review and some future research directions , 2005 .

[15]  E. J. Hickin,et al.  Radar Architecture and Evolution of Channel Bars in Wandering Gravel-Bed Rivers: Fraser and Squamish Rivers, British Columbia, Canada , 2005 .

[16]  J. Best,et al.  Three-Dimensional Sedimentary Architecture of a Large, Mid-Channel Sand Braid Bar, Jamuna River, Bangladesh , 2003 .

[17]  J. Bridge Rivers and Floodplains: Forms, Processes, and Sedimentary Record , 2003 .

[18]  J. Wunderlich,et al.  High-resolution sub-bottom profiling using parametric acoustics , 2003 .

[19]  S. Leclair Preservation of cross‐strata due to the migration of subaqueous dunes: an experimental investigation , 2002 .

[20]  J. Bridge,et al.  Quantitative Interpretation of Sedimentary Structures Formed by River Dunes , 2001 .

[21]  J. Bridge,et al.  Interpreting the Dimensions of Ancient Fluvial Channel Bars, Channels, and Channel Belts from Wireline-Logs and Cores , 2000 .

[22]  N. Lancaster,et al.  The sedimentary structure of linear sand dunes , 2000, Nature.

[23]  J. Alexander,et al.  Sedimentary facies from GPR surveys of the modern, upper Burdekin River of north Queensland, Australia: consequences of extreme discharge fluctuations , 1999 .

[24]  J. Bridge,et al.  Large‐scale structure of Calamus River deposits (Nebraska, USA) revealed using ground‐penetrating radar , 1998 .

[25]  J. Bridge,et al.  Preservation of planar laminae due to migration of low‐relief bed waves over aggrading upper‐stage plane beds: comparison of experimental data with theory , 1997 .

[26]  Fei Wang,et al.  Preservation of Cross-strata Due to Migration of Subaqueous Dunes Over Aggrading and Non-aggrading Beds: Comparison of Experimental Data with Theory , 1997 .

[27]  J. Bridge,et al.  Large-scale structure of Calamus River deposits revealed using ground-penetrating radar , 1997 .

[28]  Charles S Bristow,et al.  Internal structure of aeolian dunes in Abu Dhabi determined using ground‐penetrating radar , 1996 .

[29]  L. Borgman,et al.  Reconstructing random topography from preserved stratification , 1991 .