Alternating asymmetric topography of the Alaska range along the strike-slip Denali fault: Strain partitioning and lithospheric control across a terrane suture zone

Paul G. Fitzgerald, Sarah M. Roeske, Jeffery A. Benowitz, Steven J. Riccio, Stephanie E. Perry, Phillip A. Armstrong

Research output: Research - peer-reviewArticle

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Abstract

Contrasting lithospheric strength between terranes often results in the concentration of strain and deformation within the weaker material. Dramatic alternating asymmetric topography of the central and eastern Alaska Range along the active Denali fault is due to contrasting lithospheric strength between terranes and a suture zone, controlled by fault location with respect to the irregular boundary of a relatively stronger terrane backstop. Highest topography and greatest Neogene exhumation in the central Alaska Range occur on the concave side of the arcuate Denali fault, yet to the north and on the convex side of the fault in the eastern Alaska Range. The Denali fault largely lies along a Mesozoic suture zone between two large composite terranes (Yukon and Wrangellia composite terranes: YCT and WCT), but the McKinley strand of the fault cuts across an embayment of weaker suture-zone rocks (Alaska Range suture-zone, ARSZ) within the irregular southern boundary of the YCT (Hines Creek fault). Deformation (and uplift of the Alaska Range) is driven by slip and partitioning of strain along the Denali fault, occurring preferentially in weaker rocks of the ARSZ against the stronger YCT. Where the YCT lies well north of the McKinley strand, deformation is primarily to the north of the fault (eastern Alaska Range). Where the YCT is close to the fault, deformation is primarily to the south (central Alaska Range). While the trace of the McKinley strand approximates a small circle, two restraining bends (McKinley and Hayes) pinned equidistant from the ends of this strand localize uplift and exhumation.

LanguageEnglish (US)
Pages1519-1533
Number of pages15
JournalTectonics
Volume33
Issue number8
DOIs
StatePublished - Aug 1 2014

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strain partitioning
suture zone
strike-slip fault
terrane
topography
Strike-slip faults
Topography
slip
Rocks
Composite materials
strands
Electric fault location
rocks
composite materials
exhumation
uplift
weak rock
active fault
Neogene
partitioning

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

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Alternating asymmetric topography of the Alaska range along the strike-slip Denali fault : Strain partitioning and lithospheric control across a terrane suture zone. / Fitzgerald, Paul G.; Roeske, Sarah M.; Benowitz, Jeffery A.; Riccio, Steven J.; Perry, Stephanie E.; Armstrong, Phillip A.

In: Tectonics, Vol. 33, No. 8, 01.08.2014, p. 1519-1533.

Research output: Research - peer-reviewArticle

Fitzgerald, Paul G. ; Roeske, Sarah M. ; Benowitz, Jeffery A. ; Riccio, Steven J. ; Perry, Stephanie E. ; Armstrong, Phillip A./ Alternating asymmetric topography of the Alaska range along the strike-slip Denali fault : Strain partitioning and lithospheric control across a terrane suture zone. In: Tectonics. 2014 ; Vol. 33, No. 8. pp. 1519-1533
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