Modeling stratigraphy formed by prograding Gilbert deltas

E. Viparelli, A. Blom, Gary Parker

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

A numerical model that predicts the stratigraphy of a prograding Gilbert delta is presented. Such a Gilbert delta is formed when a river is flowing into a deep basin and the sediment transported by the river downstream avalanches downa steep slope.These deltas are characterized by thin and relatively low-slope topsets, steep foresets (the prograding slip faces), and thin, fine-grained bottomsets. Bedforms such as dunes, bars and Gilbert deltas prograde through avalanching of sediment down the slip face, in which a vertical sorting pattern develops, with the coarser sediment preferentially deposited at lower elevations. We describe the stratigraphy formed by such a prograding delta in case of a variable base level by coupling the Hirano active layer model for the topset to a lee face-sorting model for the foreset. Numerical simulations are performed at laboratory scale. Base level varies as a cosine function with constant amplitude and variable frequency, so representing cycles of base level. The main result is that low-frequency oscillations of base level are recorded in the stratigraphy of a Gilbert delta, which offers possibilities for future interpretations of base level variations from measured stratigraphy.

Original languageEnglish (US)
Title of host publicationRiver Flow 2012 - Proceedings of the International Conference on Fluvial Hydraulics
Pages827-836
Number of pages10
StatePublished - Nov 1 2012
EventInternational Conference on Fluvial Hydraulics, River Flow 2012 - San Jose, Costa Rica
Duration: Sep 5 2012Sep 7 2012

Publication series

NameRiver Flow 2012 - Proceedings of the International Conference on Fluvial Hydraulics
Volume1

Other

OtherInternational Conference on Fluvial Hydraulics, River Flow 2012
CountryCosta Rica
CitySan Jose
Period9/5/129/7/12

ASJC Scopus subject areas

  • Fluid Flow and Transfer Processes
  • Geotechnical Engineering and Engineering Geology

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