Straight from the source’s mouth: controls on field constrained sediment export across the entire active Corinth rift, central Greece
Straight from the source’s mouth: controls on field constrained sediment export across the entire active Corinth rift, central Greece
The volume and grain-size of sediment supplied from catchments fundamentally control basin stratigraphy. Despite their importance, few studies have constrained sediment budgets and grain-size exported into an active rift at the basin scale. Here, we used the Corinth Rift as a natural laboratory to quantify the controls on sediment export within an active rift. In the field, we measured the hydraulic geometries, surface grain-sizes of channel bars and full-weighted grain-size distributions of river sediment at the mouths of 47 catchments draining the rift (constituting 83% of the areal extent). Results show that the sediment grain-size increases westward along the southern coast of the Gulf of Corinth, with the coarse-fraction grain-sizes (84th percentile of weighted grain-size distribution) ranging from approximately 19 to 91 mm. We find that the median and coarse-fraction of the sieved grain-size distribution are primarily controlled by bedrock lithology, with late Quaternary uplift rates exerting a secondary control. Our results indicate that grain-size export is primarily controlled by the input grain-size within the catchment and subsequent abrasion during fluvial transport, both quantities that are sensitive to catchment lithology. We also demonstrate that the median and coarse-fraction of the grain-size distribution are predominantly transported in bedload; however, typical sand-grade particles are transported as suspended load at bankfull conditions, suggesting disparate source-to-sink transit timescales for sand and gravel. Finally, we derive both a full Holocene sediment budget and a grain-size-specific bedload discharged into the Gulf of Corinth using the grain-size measurements and previously published estimates of sediment fluxes and volumes. Results show that the bedload sediment budget is primarily comprised (~79%) of pebble to cobble grade (0.475–16 cm). Our results suggest that the grain-size of sediment export at the rift scale is particularly sensitive to catchment lithology and fluvial mophodynamics, which complicates our ability to make direct inferences of tectonic and palaeoenvironmental forcing from local stratigraphic characteristics.
1600-1625
Watkins, Stephen
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Whittaker, Alexander
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Bell, Rebecca
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Brooke, Sam
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Ganti, Vamsi
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Gawthorpe, Robert
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Mcneill, Lisa
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Nixon, Casey
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1 December 2020
Watkins, Stephen
b659176b-a9d9-41ac-a6b2-af748e316b1c
Whittaker, Alexander
e5d4b987-59c8-4852-8e67-916ff334b938
Bell, Rebecca
6ae1b7e9-eca2-4785-a40a-80b6ff58062a
Brooke, Sam
83ca5c8e-fc37-4507-82ed-1b901e5a4360
Ganti, Vamsi
1528f413-07c7-4a5f-9876-4710190d0306
Gawthorpe, Robert
a3c15d93-52d4-41a7-b51e-d8ed0adb4ee0
Mcneill, Lisa
1fe6a1e0-ca1a-4b6f-8469-309d0f9de0cf
Nixon, Casey
18e290c7-3f4b-43d0-9118-0f3ac926aadd
Watkins, Stephen, Whittaker, Alexander, Bell, Rebecca, Brooke, Sam, Ganti, Vamsi, Gawthorpe, Robert, Mcneill, Lisa and Nixon, Casey
(2020)
Straight from the source’s mouth: controls on field constrained sediment export across the entire active Corinth rift, central Greece.
Basin Research, 32 (6), .
(doi:10.1111/bre.12444).
Abstract
The volume and grain-size of sediment supplied from catchments fundamentally control basin stratigraphy. Despite their importance, few studies have constrained sediment budgets and grain-size exported into an active rift at the basin scale. Here, we used the Corinth Rift as a natural laboratory to quantify the controls on sediment export within an active rift. In the field, we measured the hydraulic geometries, surface grain-sizes of channel bars and full-weighted grain-size distributions of river sediment at the mouths of 47 catchments draining the rift (constituting 83% of the areal extent). Results show that the sediment grain-size increases westward along the southern coast of the Gulf of Corinth, with the coarse-fraction grain-sizes (84th percentile of weighted grain-size distribution) ranging from approximately 19 to 91 mm. We find that the median and coarse-fraction of the sieved grain-size distribution are primarily controlled by bedrock lithology, with late Quaternary uplift rates exerting a secondary control. Our results indicate that grain-size export is primarily controlled by the input grain-size within the catchment and subsequent abrasion during fluvial transport, both quantities that are sensitive to catchment lithology. We also demonstrate that the median and coarse-fraction of the grain-size distribution are predominantly transported in bedload; however, typical sand-grade particles are transported as suspended load at bankfull conditions, suggesting disparate source-to-sink transit timescales for sand and gravel. Finally, we derive both a full Holocene sediment budget and a grain-size-specific bedload discharged into the Gulf of Corinth using the grain-size measurements and previously published estimates of sediment fluxes and volumes. Results show that the bedload sediment budget is primarily comprised (~79%) of pebble to cobble grade (0.475–16 cm). Our results suggest that the grain-size of sediment export at the rift scale is particularly sensitive to catchment lithology and fluvial mophodynamics, which complicates our ability to make direct inferences of tectonic and palaeoenvironmental forcing from local stratigraphic characteristics.
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e-pub ahead of print date: 3 March 2020
Published date: 1 December 2020
Additional Information:
© 2020 The Authors. Basin Research published by International Association of Sedimentologists and European Association of Geoscientists and Engineers and John Wiley & Sons Ltd.
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Local EPrints ID: 467627
URI: http://eprints.soton.ac.uk/id/eprint/467627
ISSN: 0950-091X
PURE UUID: 9dbce1ac-2a99-4540-9e2b-d65d2f447570
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Date deposited: 15 Jul 2022 19:21
Last modified: 17 Mar 2024 02:52
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Author:
Stephen Watkins
Author:
Alexander Whittaker
Author:
Rebecca Bell
Author:
Sam Brooke
Author:
Vamsi Ganti
Author:
Robert Gawthorpe
Author:
Casey Nixon
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