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Extreme deformation of carbonates (seismic, landslides and impacts)

Carbonates do not behave like any other rocks during extreme deformation (e.g., earthquakes, landslides or asteroid impacts) because carbonate minerals decompose upon frictional heating. These reactions produce phases such as lime, periclase, magnetite plus large volumes of carbon dioxide (CO2) gas. The sudden release of CO2 gas upon rapid movement results in drastic reduction of friction along the slip plane which, in turn, promotes high velocity slip.

 

A few examples of extreme deformation of carbonates include the Hebgen Lake Fault that produced a Mw 7.2 earthquake in 1959, the Heart Mountain Slide that resulted in the largest known (~2,000 km3) terrestrial landslide ~49 Ma ago, and Meteor Crater in Arizona where the Kaibab Formation volatilized upon asteroid impact at 18 km/s.

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Geologic cross-section of Heart Mountain Slide, Wyoming  - courtesy Steven Losh (Zamani et al., 2023)

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Hebgen Lake Fault scarp in unconsolidated sediments, Montana  - credit: J.R. Stacy, USGS, public domain (Zamani et al., in progress)

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Meteor Crater, Arizona – 50,000 years old impact on Kaibab Limestone

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