Abstract
Formation and evolution of the basal layer in large landslides has important implications for processes that reduce frictional resistance to sliding. In this report, we show that zircon geochronology and tectonic provenance can be used to investigate the basal layer of the gigantic-scale Markagunt gravity slide of Utah, USA. Basal layer and clastic injectite samples have unique tectonic chronofacies that identify the rock units that were broken down during emplacement. Our results show that basal material from sites on the former land surface is statistically indistinguishable and formed primarily by the breakdown of upper plate lithologies during sliding. Decapitated injectites have a different tectonic chronofacies than the local basal layer, with more abundant lower plate-derived zircons. This suggests clastic dikes formed earlier in the translation history from a structurally deeper portion of the slide surface and a compositionally different basal layer before being translated to their current position.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 449-457 |
| Number of pages | 9 |
| Journal | Terra Nova |
| Volume | 34 |
| Issue number | 5 |
| DOIs | |
| State | Published - Oct 2022 |
| Externally published | Yes |
Bibliographical note
Funding Information:Funding for this research was provided by the National Science Foundation (EAR2113158), the Utah Geological Survey, the Illinois State University Foundation, the Kent State University Research Council and the Geological Society of America through sponsorship of a Thompson Field Forum.
Publisher Copyright:
© 2022 The Authors. Terra Nova published by John Wiley & Sons Ltd.