Article
 

Crustal-scale structural architecture, shortening, and exhumation of an active, eroding orogenic wedge (Chugach/St Elias Range, southern Alaska)

Pubblico Deposited

Contenuto scaricabile

Scarica il pdf
https://ir.library.oregonstate.edu/concern/articles/tx31qk28z

Descriptions

Attribute NameValues
Creator
Abstract
  • Active mountain building associated with the accretion of the Yakutat microplate (YT) in southern Alaska is characterized through the combination of a new balanced cross section and new low-temperature cooling ages. This analysis constrains the amount and timing of shortening, the spatial and temporal trends of exhumation, and the interplay between structural development and exhumation. A fold-and-thrust belt comprising three principal thrust sheets (the Hope Creek, Sullivan, and an offshore thrust sheet from north to south) characterizes the YT internal structure, which has absorbed a minimum of ~82 km shortening. Assuming shortening and foreland basin development occurred contemporaneously, the shortening rate across the YT is ~13–14 mm/a after 5.6 Ma. Detrital apatite fission track ages, from south to north, are unreset along the southern edge of the Sullivan thrust sheet at the coast, are reset and have ages younger than 6.3 Ma within the thrust belt, and have reset cooling ages of ~13 Ma in the North American upper plate. Only the zircon samples from the northern, internal YT are potentially reset. Exhumation rates within the thrust belt vary from 0.3 ± 0.1 mm/a to 4 ± 1.8 mm/a. Combining the thermochronometric and structural data indicate that wedge exhumation since ~6 Ma is 500 km² and that particle trajectories have larger horizontal than vertical components. Whereas exhumation and shortening have been focused on the windward side of the Chugach/St. Elias Range since ~6 Ma, the cooling ages do not uniquely distinguish between orographically versus tectonically controlled erosion.
  • Keywords: exhumation, microplate, fold-and-thrust belt
  • Keywords: exhumation, microplate, fold-and-thrust belt
Resource Type
DOI
Date Available
Date Issued
Citation
  • Meigs, A., S. Johnston, J. Garver, and J. Spotila (2008), Crustal-scale structural architecture, shortening, and exhumation of an active, eroding orogenic wedge (Chugach/St Elias Range, southern Alaska), Tectonics, 27, TC4003, doi:10.1029/2007TC002168.
Journal Title
Journal Volume
  • 27
Journal Issue/Number
  • TC4003
Dichiarazione dei diritti
Funding Statement (additional comments about funding)
  • Research was supported by NSF grant EAR-0001192 and NASA grant NASA (NAG-5-7646). Steve Reese and the OSU Triga Radiation Center are thanked for irradiation of our samples.
Publisher
Peer Reviewed
Language
Replaces

Le relazioni

Parents:

This work has no parents.

Elementi

Thumbnail Titolo Data caricata Visibilità Azioni
file details MeigsAndrewCEOASCrustalScaleStructural.pdf 2017-07-24 Pubblico Scaricare