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| Titel |
Catastrophic emplacement of giant landslides aided by thermal decomposition: Heart Mountain, Wyoming. |
| VerfasserIn |
Thomas Mitchell, Steven Smith, Mark Anders, Giulio Di Toro, Stefan Nielsen, Andrea Cavallo, Andrew Beard |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250109685
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| Publikation (Nr.) |
 EGU/EGU2015-9620.pdf |
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| Zusammenfassung |
| The Heart Mountain landslide of northwest Wyoming is the largest known sub-aerial
landslide on Earth. During its emplacement more than 2,000 km3 of Paleozoic
sedimentary and Eocene volcanic rocks slid >45 km on a basal detachment surface
dipping 2Ë , leading to 100 years of debate regarding the emplacement mechanisms.
Recently, emplacement by catastrophic sliding has been favored, but experimental
evidence in support of this is lacking. Here we show in friction experiments on
carbonate rocks taken from the landslide that at slip velocities of several meters per
second CO2starts to degas due to thermal decomposition induced by flash heating
after only a few hundred microns of slip. This is associated with the formation of
vesicular degassing rims in dolomite clasts and a crystalline calcite cement that
closely resemble microstructures in the basal slip zone of the natural landslide.
Our experimental results are consistent with an emplacement mechanism whereby
catastrophic slip was aided by carbonate decomposition and release of CO2, allowing
the huge upper plate rock mass to slide over a ‘cushion’ of pressurized material. |
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