Quantifying the sensitivity of distributive fluvial systems to changes in sediment supply and lake level using stratigraphic forward modelling

Snieder, S., Griffiths, C. M., Howell, J. A., Hartley, A. J. and Owen, A. (2023) Quantifying the sensitivity of distributive fluvial systems to changes in sediment supply and lake level using stratigraphic forward modelling. Sedimentology, 70(7), pp. 2196-2219. (doi: 10.1111/sed.13118)

Abstract

Stratigraphic forward modelling has been used to quantify the sensitivity of sandbody connectivity in a distributive fluvial system to changes in sediment supply and lake level. Recent stratigraphic forward modelling using SedsimX from StrataMod Pty Limited of the Oligocene to Miocene Huesca distributive fluvial system in northern Spain was used as a base‐case for this sensitivity analysis. Based on literature research and initial modelling, a sediment supply sensitivity range of 0.22 to 21.85 km3/kyr and lake‐level sensitivity range of −1000 to 1000 mm/kyr were used. Results show that the stratigraphic architecture of the modelled distributive fluvial system is more sensitive to changes in sediment supply than to changes in lake level. While an increase in the rate of sediment supply results in an increase in preserved average grain size, aggradation rates and sandbody connectivity at the same distance from the apex, the average grain size, aggradation rate and sandbody connectivity all decrease with increasing distance from fan apex. The main difference in the stratigraphic architecture can be found in the proximal zones. Only oversupplied models, with much higher sediment supply than the base‐case, deposited fully amalgamated channelized deposits with laterally continuous, tabular beds with occasional scoured surfaces. Models with base‐case sediment supply contain channelized sandy deposits within a fine‐grained floodplain environment. Models with sediment supply much lower than the base‐case had no deposition in the proximal zone. Lake‐level rise leads to reduced distal erosion of sediments, concentration of silts close to the lake shore, and higher aggradation rates and thicker sandbodies in the proximal zone. The sensitivity analysis highlights that the parameters governing the formation of distributive fluvial systems have different weightings but are ultimately all interconnected and interdependent. This quantitative framework can be used as a predictive tool for subsurface exploration in distributive fluvial systems.

• Item Type: Articles
• Additional Information: This study was part of a doctoral project financed through a studentship by the United Kingdom Research and Innovation Centre for Doctoral Training in Oil and Gas, which was institution-ally funded by the University of Aberdeen, United Kingdom.
• Keywords: Sensitivity analysis, distributive fluvial systems, sediment supply, lake‐level change, stratigraphic forward modelling, quantitative sedimentology.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Howell, Dr John and Owen, Dr Amanda
• Authors: Snieder, S., Griffiths, C. M., Howell, J. A., Hartley, A. J., and Owen, A.
• College/School: College of Science and Engineering > School of Engineering > Systems Power and Energy; College of Science and Engineering > School of Geographical and Earth Sciences
• Journal Name: Sedimentology
• Publisher: Wiley
• ISSN: 0037-0746
• ISSN (Online): 1365-3091
• Published Online: 23 May 2023
• Copyright Holders: Copyright © 2023 The Authors
• First Published: First published in Sedimentology 70(7):2196-2219
• Publisher Policy: Reproduced under a Creative Commons licence