Kinematic evidence for downdip movement on the Mormon Peak detachment

Publication Type  Journal Article
Year of Publication  2007
Authors  Walker, C. D.; Anders, M. H.; Christie-Blick, N.
Journal Title  Geology
Volume  35
Issue  3
Pages  259-262
Journal Date  Mar
ISBN Number  0091-7613
Accession Number  ISI:000247627700017
Key Words  detachment faults; basin and range province; gravity sliding; mormon peak detachment; crustal extension; virgin river depression; southeastern nevada; southern nevada; tectonics; mountains; arizona; orogen; basin
Abstract  

The Mormon Peak detachment is considered to be one of the best examples of a rooted upper crustal detachment fault that propagated through the brittle crust at a low angle. The hanging wall of the detachment today consists of a number of isolated blocks that have been interpreted as remnants of a once-contiguous extensional allochthon. Here we present the results of a new study of directional indicators from the basal surfaces beneath these blocks. These measurements do not agree with the long-standing interpretation of a S75 degrees W movement direction for the detachment hanging wall. Instead, the most recent movement on each section of the detachment took place approximately parallel to the present downdip direction. We conclude that the Mormon Peak detachment is best explained as the basal surfaces to a series of rootless gravity slides.

Notes  

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URL  <Go to ISI>://000247627700017
DOI  Doi 10.1130/G23396a.1