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| Titel |
Erosional flux from tectonically active landscapes: Case studies from Southern Italy |
| VerfasserIn |
Duna Roda-Boluda, Mitch D'Arcy, Alex Whittaker, Philip Allen, Delia Gheorghiu, Angel Rodes |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250121726
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| Publikation (Nr.) |
 EGU/EGU2016-557.pdf |
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| Zusammenfassung |
| Erosion and sediment supply are fundamentally important controls on landscape evolution,
governing the denudation of relief, the stratigraphy deposited in basins, and the
ultimate destruction of orogens. However, quantifying the rates, timescales, and
predominant processes of erosion remains a major challenge in many tectonically active
areas.
Here, we use Southern Italy as a case study to demonstrate how these challenges can be
overcome. We present 15 new 10Be catchment-averaged erosion rates, for systems
distributed along 5 active normal faults for which we have excellent constraints on
throw rates along strike and uplift history. These footwall catchments have a total
relief of up to 1800 m and throw rates up to 1.4 mm/yr. We show that sediment
supply estimates based on the 10Be erosion rates agree well with sediment supply
predictions based on the fault throw profiles. Our results suggest that about 80% of the
material uplifted by the faults is being eroded at a similar magnitude to the fault throw
rates, offering new insights into the topographic balance of uplift and erosion in this
area.
These findings imply that active normal faulting is the primary control on sediment
supply in Southern Italy. Our field observations suggest that landslides are an important
source of sediment in our study area, and are largely driven by incision in response to fault
activity. Using a field-calibrated landslide inventory, we estimate landslide-derived sediment
flux for our sampled catchments. These estimates correlate well with total sediment flux
estimates, demonstrating quantitatively that landslides must be a major source of sediment.
Their erosional signal is adequately captured by the 10Be analyses most likely because of the
high frequency of small landslides and their high spatial density in these catchments
(typically >10% of the total area), which ensures sufficient sediment mixing. Finally, we
use our results to calibrate the BQART model of sediment supply, enabling us to
make sediment flux predictions for a total of 158 similar catchments along 8 studied
active normal faults in Southern Italy. This large dataset offers an unprecedented
opportunity to study how erosional sediment fluxes relate to fault activity and landsliding. |
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