Impact of recycling and lateral sediment input on grain size fining trends—Implications for reconstructing tectonic and climate forcings in ancient sedimentary systems
File(s)clean_manuscript_PURE_database.pdf (3.04 MB)
Accepted version
Author(s)
Harries, RM
Kirstein, LA
Whittaker, AC
Attal, M
Main, I
Type
Journal Article
Abstract
Grain size trends in basin stratigraphy are thought to preserve a rich record of the climatic and tectonic controls on landscape evolution. Stratigraphic models assume that over geological timescales, the downstream profile of sediment deposition is in dynamic equilibrium with the spatial distribution of tectonic subsidence in the basin, sea level and the flux and calibre of sediment supplied from mountain catchments. Here, we demonstrate that this approach in modelling stratigraphic responses to environmental change is missing a key ingredient: the dynamic geomorphology of the sediment routing system. For three large alluvial fans in the Iglesia basin, Argentine Andes we measured the grain size of modern river sediment from fan apex to toe and characterise the spatial distribution of differential subsidence for each fan by constructing a 3D model of basin stratigraphy from seismic data. We find, using a self-similar grain size fining model, that the profile of grain size fining on all three fans cannot be reproduced given the subsidence profile measured and for any sediment supply scenario. However, by adapting the self-similar model, we demonstrate that the grain size trends on each fan can be effectively reproduced when sediment is not only sourced from a single catchment at the apex of the system, but also laterally, from tributary catchments and through fan surface recycling. Without constraint on the dynamic geomorphology of these large alluvial systems, signals of tectonic and climate forcing in grain size data are masked and would be indecipherable in the geological record. This has significant implications for our ability to make sensitive, quantitative reconstructions of external boundary conditions from the sedimentary record.
Date Issued
2019-10
Online Publication Date
2020-02-13T07:00:20Z
Date Acceptance
2019-02-10
ISSN
0950-091X
Publisher
Wiley
Start Page
866
End Page
891
Journal / Book Title
Basin Research
Volume
31
Issue
5
Copyright Statement
© 2019 The Authors. Basin Research © 2019 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists. This is the accepted version of the following article: Harries, RM, Kirstein, LA, Whittaker, AC, Attal, M, Main, I. Impact of recycling and lateral sediment input on grain size fining trends—Implications for reconstructing tectonic and climate forcings in ancient sedimentary systems. Basin Res. 2019; 31: 866– 891, which has been published in final form at https://doi.org/10.1111/bre.12349
Identifier
https://onlinelibrary.wiley.com/doi/abs/10.1111/bre.12349
Subjects
Science & Technology
Physical Sciences
Geosciences, Multidisciplinary
Geology
basin subsidence
modelling
sediment flux
grain size
sedimentology
tectonics
SELECTIVE DEPOSITION
LANDSCAPE EVOLUTION
COSMOGENIC NUCLIDES
EROSION RATES
ALLUVIAL FANS
IGLESIA BASIN
RIVER
GRAVEL
BED
FLUX
Geology
04 Earth Sciences
Publication Status
Published
Date Publish Online
2019-02-13