Compensational Stacking Which Is Defined As the Tendency of Sediment Transport Processes

Signature of non-locality in depositional systems: Implications for modeling and interpretation of stratigraphic records

Vamsi Ganti, Kyle Straub, Efi Foufoula-Georgiou and Mark Meerschaert

Compensational stacking which is defined as the tendency of sediment transport processes to fill-in topographic lows through deposition is a concept widely used in the interpretation of the stratigraphic records. Recently, a new metric called the “compensation index” was proposed to quantify the degree of compensational stacking in any depositional system and power-law trends were used to describe the decrease in standard deviation of sedimentation/subsidence with increasing averaging distance. An explanation of the observed power-law trends was given in terms of the correlation between elevation increments in time. In this work, we present a possibility of an alternative explanation for the observed power-law trends using high temporal resolution data for a delta in an experimental basin undergoing relative subsidence. We demonstrate that heavy-tailed distributions for periods of non-sedimentation and magnitudes of sedimentation events can lead to the observed phenomenon with the compensation index dependent on the tail-index of the two distributions. Further, we show that a truncated Pareto distribution and a stable density provide a good fit for the densities of periods of non-sedimentation and magnitudes of sedimentation in the experimental basin. Finally, implications of the experimentally observed heavy-tails are discussed in the context of developing transport models in depositional systems.