The role of thrust faulting in the formation of the eastern Alaska Range: Thermochronological constraints from the Susitna Glacier Thrust Fault region of the intracontinental strike-slip Denali Fault system

Steven J. Riccio, Paul G Fitzgerald, Jeff A. Benowitz, Sarah M. Roeske

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Horizontal-slip along restraining bends of strike-slip faults is often partitioned into a vertical component via splay faults. The active Susitna Glacier Thrust Fault (SGTF), as shown by its initiation of the 2002 M7.9 Denali Fault earthquake, lies south of, and intersects the dextral strike-slip Denali Fault. Geochronology and thermochronology data from samples across the SGTF constrain the region's tectonic history and the role of thrusting in the formation of the eastern Alaska Range south of the Denali fault. U-Pb zircon ages indicate intrusion of plutons in the footwall (∼57 Ma) and hanging wall (∼98 Ma). These U-Pb zircon ages correlate to those from the Ruby Batholith/Kluane Terrane ∼400 km east along the Denali Fault, supporting geologic correlations and hence constraints on long-term slip rates. 40Ar/39Ar mica and K-feldspar data from footwall and hanging wall samples (∼54 to ∼46Ma) reflect cooling following magmatism and/or regional Eocene metamorphism related to ridge subduction. Combined with apatite fission track data (ages 43-28Ma) and thermal models, both sides of the SGTF acted as a coherent block during the Eocene and early Oligocene. Contrasting apatite (U-Th)/He ages across the Susitna Glacier (∼25Ma footwall, ∼15Ma hanging wall) suggest initiation of faulting during the middle Miocene. Episodic cooling and exhumation is related to thrusting on known or hypothesized faults that progressively activate due to varying partition of strain along the Denali Fault associated with changing kinematics and plate interaction (Yakutat microplate collision, flat-slab subduction and relative plate motion change) at the southern Alaskan plate margin.

Original languageEnglish (US)
Pages (from-to)2195-2217
Number of pages23
JournalTectonics
Volume33
Issue number11
DOIs
StatePublished - Nov 1 2014

Fingerprint

Strike-slip faults
Glaciers
Faulting
glaciers
thrust fault
strike-slip fault
thrust
faulting
glacier
slip
Apatites
apatites
hanging wall
footwall
Geochronology
Cooling
cooling
geochronology
Ruby
apatite

Keywords

  • Alaska
  • Denali fault
  • Exhumation
  • Strain partitioning
  • Thermochronology
  • Thrust fault

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

Cite this

The role of thrust faulting in the formation of the eastern Alaska Range : Thermochronological constraints from the Susitna Glacier Thrust Fault region of the intracontinental strike-slip Denali Fault system. / Riccio, Steven J.; Fitzgerald, Paul G; Benowitz, Jeff A.; Roeske, Sarah M.

In: Tectonics, Vol. 33, No. 11, 01.11.2014, p. 2195-2217.

Research output: Contribution to journalArticle

@article{95bf09d2c1cc4234be150b38a369599a,
title = "The role of thrust faulting in the formation of the eastern Alaska Range: Thermochronological constraints from the Susitna Glacier Thrust Fault region of the intracontinental strike-slip Denali Fault system",
abstract = "Horizontal-slip along restraining bends of strike-slip faults is often partitioned into a vertical component via splay faults. The active Susitna Glacier Thrust Fault (SGTF), as shown by its initiation of the 2002 M7.9 Denali Fault earthquake, lies south of, and intersects the dextral strike-slip Denali Fault. Geochronology and thermochronology data from samples across the SGTF constrain the region's tectonic history and the role of thrusting in the formation of the eastern Alaska Range south of the Denali fault. U-Pb zircon ages indicate intrusion of plutons in the footwall (∼57 Ma) and hanging wall (∼98 Ma). These U-Pb zircon ages correlate to those from the Ruby Batholith/Kluane Terrane ∼400 km east along the Denali Fault, supporting geologic correlations and hence constraints on long-term slip rates. 40Ar/39Ar mica and K-feldspar data from footwall and hanging wall samples (∼54 to ∼46Ma) reflect cooling following magmatism and/or regional Eocene metamorphism related to ridge subduction. Combined with apatite fission track data (ages 43-28Ma) and thermal models, both sides of the SGTF acted as a coherent block during the Eocene and early Oligocene. Contrasting apatite (U-Th)/He ages across the Susitna Glacier (∼25Ma footwall, ∼15Ma hanging wall) suggest initiation of faulting during the middle Miocene. Episodic cooling and exhumation is related to thrusting on known or hypothesized faults that progressively activate due to varying partition of strain along the Denali Fault associated with changing kinematics and plate interaction (Yakutat microplate collision, flat-slab subduction and relative plate motion change) at the southern Alaskan plate margin.",
keywords = "Alaska, Denali fault, Exhumation, Strain partitioning, Thermochronology, Thrust fault",
author = "Riccio, {Steven J.} and Fitzgerald, {Paul G} and Benowitz, {Jeff A.} and Roeske, {Sarah M.}",
year = "2014",
month = "11",
day = "1",
doi = "10.1002/2014TC003646",
language = "English (US)",
volume = "33",
pages = "2195--2217",
journal = "Tectonics",
issn = "0278-7407",
publisher = "American Geophysical Union",
number = "11",

}

TY - JOUR

T1 - The role of thrust faulting in the formation of the eastern Alaska Range

T2 - Thermochronological constraints from the Susitna Glacier Thrust Fault region of the intracontinental strike-slip Denali Fault system

AU - Riccio, Steven J.

AU - Fitzgerald, Paul G

AU - Benowitz, Jeff A.

AU - Roeske, Sarah M.

PY - 2014/11/1

Y1 - 2014/11/1

N2 - Horizontal-slip along restraining bends of strike-slip faults is often partitioned into a vertical component via splay faults. The active Susitna Glacier Thrust Fault (SGTF), as shown by its initiation of the 2002 M7.9 Denali Fault earthquake, lies south of, and intersects the dextral strike-slip Denali Fault. Geochronology and thermochronology data from samples across the SGTF constrain the region's tectonic history and the role of thrusting in the formation of the eastern Alaska Range south of the Denali fault. U-Pb zircon ages indicate intrusion of plutons in the footwall (∼57 Ma) and hanging wall (∼98 Ma). These U-Pb zircon ages correlate to those from the Ruby Batholith/Kluane Terrane ∼400 km east along the Denali Fault, supporting geologic correlations and hence constraints on long-term slip rates. 40Ar/39Ar mica and K-feldspar data from footwall and hanging wall samples (∼54 to ∼46Ma) reflect cooling following magmatism and/or regional Eocene metamorphism related to ridge subduction. Combined with apatite fission track data (ages 43-28Ma) and thermal models, both sides of the SGTF acted as a coherent block during the Eocene and early Oligocene. Contrasting apatite (U-Th)/He ages across the Susitna Glacier (∼25Ma footwall, ∼15Ma hanging wall) suggest initiation of faulting during the middle Miocene. Episodic cooling and exhumation is related to thrusting on known or hypothesized faults that progressively activate due to varying partition of strain along the Denali Fault associated with changing kinematics and plate interaction (Yakutat microplate collision, flat-slab subduction and relative plate motion change) at the southern Alaskan plate margin.

AB - Horizontal-slip along restraining bends of strike-slip faults is often partitioned into a vertical component via splay faults. The active Susitna Glacier Thrust Fault (SGTF), as shown by its initiation of the 2002 M7.9 Denali Fault earthquake, lies south of, and intersects the dextral strike-slip Denali Fault. Geochronology and thermochronology data from samples across the SGTF constrain the region's tectonic history and the role of thrusting in the formation of the eastern Alaska Range south of the Denali fault. U-Pb zircon ages indicate intrusion of plutons in the footwall (∼57 Ma) and hanging wall (∼98 Ma). These U-Pb zircon ages correlate to those from the Ruby Batholith/Kluane Terrane ∼400 km east along the Denali Fault, supporting geologic correlations and hence constraints on long-term slip rates. 40Ar/39Ar mica and K-feldspar data from footwall and hanging wall samples (∼54 to ∼46Ma) reflect cooling following magmatism and/or regional Eocene metamorphism related to ridge subduction. Combined with apatite fission track data (ages 43-28Ma) and thermal models, both sides of the SGTF acted as a coherent block during the Eocene and early Oligocene. Contrasting apatite (U-Th)/He ages across the Susitna Glacier (∼25Ma footwall, ∼15Ma hanging wall) suggest initiation of faulting during the middle Miocene. Episodic cooling and exhumation is related to thrusting on known or hypothesized faults that progressively activate due to varying partition of strain along the Denali Fault associated with changing kinematics and plate interaction (Yakutat microplate collision, flat-slab subduction and relative plate motion change) at the southern Alaskan plate margin.

KW - Alaska

KW - Denali fault

KW - Exhumation

KW - Strain partitioning

KW - Thermochronology

KW - Thrust fault

UR - http://www.scopus.com/inward/record.url?scp=84916899643&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84916899643&partnerID=8YFLogxK

U2 - 10.1002/2014TC003646

DO - 10.1002/2014TC003646

M3 - Article

AN - SCOPUS:84916899643

VL - 33

SP - 2195

EP - 2217

JO - Tectonics

JF - Tectonics

SN - 0278-7407

IS - 11

ER -