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65º
60º
RubyRuby
160º
160º
155º
155º 150º 145º
Yukon-TananaYukon-Tanana
BrooksBrooks
W
PrinceWilliamPrinceWilliam
Kaltag Fault
TintinaFaultTintinaFault
Denali Fault
Con
tact
F
Bord
er R
ange
s FAle
utia
n Tre
nch
TransitionFault
PACIFICPLATE
YakutatYakutat
KoyukukKoyukukRubyRuby
TT
T
T
SMSM
A
ChugachChugach
70º
AnchorageAnchorage
FairbanksFairbanks
WrangelliaWrangellia
Peni
nsul
ar
Peni
nsul
ar
NFNF
DL/NFDL/NF
Kobu -k SouthForkFaultKobuk- SouthForkFault
AP-W-McAP-W-Mc
ALAL
A Terrane maps
TintinaFault
Fra
ser
Fau
ltF
rase
rF
ault
Rocky
Rocky
TrenchTrench
Mountain
Mountain
Queen
Charlotte
Fairw
eatherF
ault
Transition
Fault Co
astS
hear
Zo
ne
Co
astS
hear
Zo
ne
Fold&
Thrust Belt
Denali Fault
Denali Fault
Stikinia
Nah
anni
Fort
Sim
pson
Hot
tah
QN
QN
KO
MOMO
QN
CA
CA
CC
CC
WR
WR
AX
AX
YCHCH
SMSM
SMSMKOKO
NSNS
KOKO
OL CRCR PR
SC-FF
MT
CD
HA
BRBR
PACIFICPLATE
JUANDE FUCA
PLATE
Outer TerranesChugach
Crescent
Olympic
Pacific Rim
Prince William
Yakutat
Insular TerranesAlexander
Peninsular
Wrangellia
AX
WR
Y
CHCROLPR
Intermontane TerranesCache CreekQuesnelliaStikiniaWindy-Maclaren-
Bridge RiverCadwallader-MethowEaston & MelangeHarrison-Nooksack
Aurora Peak
CCQN
W
HA
BR
Alaskan TerranesAngayucham
KootenayYukon-Tanana
Koyukuk
Monashee
North Fork
Ruby
Slide Mountain
Tozitna
A
KO-YT
CA-MT NFNFR
SMT
Omineca & CentralAlaskan Terranes
Plutonics & UndividedMetamorphics
Seismic ProfilesReflection (used)
Reflection (not used)
R/WAR (used)
R/WAR (not used)
FaultsStrike-slip
Subduction
Thrust front?
NS
ContinentalNorth Slope (Foreland)
Brooks Range
Cassiar
Foreland Fold & Thrust Belt
Nisling
DisplacedContinental Margin
ContinentalProterozoic
Archean
North AmericanAncestral Basement
MO
WhitehorseWhitehorse
PrinceRupertPrinceRupert
CalgaryCalgary
EdmontonEdmonton
SeattleSeattle
0 500Distance (km)
RangeRange
North SlopeNorth Slope
Copper River Basin
FairbanksSE-NW SE-NW SE-NWS-N
B Alaskan Cordillera
7.87.55
7.88.28.2
6.7 6.67.1
6.7
4.05.04.0
6.4 6.26.2 5.86.2 5.2
6.56.55 6.56.5
6.06.0
TACTMid[Beaudoin et al., 1994]
TACTS[Fuis and Plafker, 1991; Fisher et al., 1989]
TACTOffshore[Brocher et al., 1994]
Peninsular Wrangellia Yukon-TananaChugach
OUTER TERRANES FORELANDINSULAR
Prince William
AleutianTrench
ContactFault
Border RangesFault System
West ForkFault System
DenaliFault
Beaver CreekFault
Victoria CreekFault
WickershamWhite Mtns
LM Tozitna
Schwatka
Ruby
Prospect Ck
T
Koyukuk
Brooks Range North Slope
Angayucham
Slate CreekTintina Fault Zone?
TozitnaFault
Kobuk-S.ForkFault
WisemanFault
ToyukFault
AtigunFault
Refraction velocityRefraction velocity
CENTRAL
FairbanksSE-NW SE-NW SE-NWS-N
AleutianTrench
ContactFault
Border RangesFault System
West ForkFault System
DenaliFault
Beaver CreekFault
Victoria CreekFault
TozitnaFault
Kobuk-S.ForkFault
WisemanFault
ToyukFault
AtigunFault
6.8
6.4
6.5 6.2 6.26.4
6.1
6.85
6.46.1
7.06.7 6.35
7.4
5.9 4.0 5.0 5.5
8.3 8.2
8.28.2 7.97.0
7.27.8
TACTN[Fuis et al., 1997; Wissinger et al., 1997]
1300 1400
Aleutian MegathrustInterface
W-E Offset300 km
?
?
?
?
?Pacific PlateLithospheric Mantle
Yakutat
Underthrust/Accreted?
North American (Alaskan) Lithospheric Mantle
Asthenosphere
epolShtroNIndentor
?120120
Interpretation1300 1400
1964 Mw9.2
[Brocher et al., 2004; Fisher et al., 2005]
C Northern Canadian Cordillera
SW-NE NW-SESW-NE W-E
Reflection fabricReflection fabric
0
8
16
24
32
Tim
e(s
)
[Cook et al., 1999][Cook et al., 2004; Evenchick et al., 2005][Cook et al., 2004; Evenchick et al., 2005][Morozov et al., 1998]
0
8
16
24
32
Tim
e(s)SNORCLE Line 1SNORCLE Line 2BSNORCLE Line 2AACCRETE
Refraction velocityRefraction velocity
[Spence and Asudeh, 1993; Dehler and Clowes, 1988]
[Morozov et al., 1998, 2001]
[Hammer et al., 2000]
[Hammer and Clowes, 2004] [Welford et al., 2001] [Fernandez-Viejo et al., 2003]
Tintina FaultKechika Fault Muskwa Anticlinorium W. Canada Sed. BasinStikine ArchBowser BasinCoast Shear ZoneQueen Charlotte Fault
Pacific OceanQ.C.
Islands Dease LakeWatson
LakeFort
NelsonNahanni
ButteHecate Strait Prince Rupert
Stewart
Queen CharlotteTraverse
ACCRETE
ACCRETE
SNORE Line 22 SNORE Line 21 SNORE Line 11
SW-NE SSW-NNE NW-SE W-E
S-N Offset(200 km)
PACIFIC INSULAR COAST BELT INTERMONTANE OMINECA FORELAND WOPMAY
Stikinia CCAX Coast Plutonic ComplexWrangelliaPacific Plate CA SM Cassiar KO-YT Nahanni Fort SimpsonFold and Thrust Belt
Asthenosphere
North AmericanAncestral Basement
Folded and imbricated crust includingNorth American ancestral basement
North American Lithospheric MantleNorth American Lithospheric Mantle
North American Lithospheric MantleNorth American Lithospheric Mantle
Pacific PlateLithospheric Mantle
Pacific PlateLithospheric Mantle
??
??
InterpretationInterpretation
Northern Cordillera Volcanic ProvinceHottah
D Southern Canadian Cordillera
N-SEN-WS E-WE-WE-WE-WSW-NE0
8
16
24
Tim
e(s
)
Reflection fabricReflection fabric
0
8
16
Tim
e(s)
85-3 85-9
51611-48 14 13 12 11 10 4 3 2 19 8 7
QN
Asthenosphere
Asthenosphere
North American Lithospheric Mantle
North American Lithospheric Mantle
Juan de Fuca
eltnaMcirehpsohtiL
WrangelliaJuan de Fuca Plate Plutonic Complex CD SBHAHA BR Quesnellia Kootenay Fold and Thrust BeltINSULAR COAST BELT INTERMONTANE OMINECA FORELAND CRATONPACIFIC
Rocky Mtn Trench Thrust & FoldBelt
Western CanadaSedimentary Basin
SLFVernonAntiform
Nicola HorstGaribaldi Volcanic Belt Fraser Fault
WCFMonashees Purcells RockiesOkanagan L.
120Interpretation
VancouverVancouver IslandSeamountRidge
Rocky Mtn Trench Thrust & FoldBelt
Western CanadaSedimentary Basin
SLFVernonAntiform
Nicola HorstFraser Fault
Monashees Purcells Rockies
AW
Wrangellia
E
C
C
North American Ancestral Basement
[Burianyk and Kanasewich, 1995][McLean and Spence, 1994][Zelt et al., 1993] [Zelt and White, 1995] [Chandra and Cumming, 1972][Drew and Clowes, 1990][Cudrak and Clowes, 1993]
6.0
7.9
5.0
8.38.0
8.28.0
5.85.86.1
6.46.5
6.26.2 6.26.66.6 6.5 6.3
8.06.66.6
7.2
Refraction velocityRefraction velocityN-S Offset
70 kmN-S Offset
60 kmS-N Offset
100 km
SW-NEVancouverVancouver Island
E-WEN-WS SW-NE W-E
SCoRE 7VISP Line PJSEISRIDG-85
[Cook et al., 1992]SC 1-12
[Varsek et al., 1993; Bustin et al., 2007, personal commun.]SC 13-16
120
7.8 8.0
85-1
SCoRE 3[Ramachandran et al., 2006]
SHIPS
[Hyndman et al., 1990]
[Clowes et al.,1987b]
[Clowes et al.,1987a]
[Rohr et al.,1988]
[Hasselgren & Clowes, 1995]
SCoRE 2 SCoRE 9
30 31
6.66.2
7.06.6
7.06.66.66.8
6.87.0 6.8
6.6
8.0
6.25.8
7.87.67.6 7.85
Teleseismic interpretations:continental Mohooceanic crustoceanic crust
[Nicholson et al., 2005][Nicholson et al., 2005][Bostock and Vandecar, 1995]
Active source interpretation:duplexed crust [Calvert et al., 2006]
Cascadia MegathrustInterface
?
?
?
W. Canada
7.8
dezinitnepreSMantle
dezinitnepreSMantle
E
[Lemieux et al., 2000]Alberta Basement
Geological Society of America Special Paper 433Whence the Mountains? Inquiries into the Evolution of Orogenic Systems: A Volume in Honor of Raymond A. PriceEdited by James W. Sears, Tekla A. Harms, and Carol A. Evenchick
From Chapter 5, “Lithospheric-scale structures across the Alaskan and Canadian Cordillera: Comparisons and tectonic implications,” by P.T.C. Hammer and R.M. Clowes
© 2007 The Geological Society of AmericaPrinted in the USA
Figure 2. Comparison of merged interpretations, seismic-refl ection profi les, and seismic velocity structure models for the southern Canadian Cordillera, northern Canadian Cordillera (Slave-Northern Cordillera Lithospheric Evolution [SNORCLE], ACCRETE, Queen Charlotte transects), and Alaskan Cordillera (Trans-Alaska Crustal Transect [TACT]) corridors, doi: 10.1130/2007.2433(05).F2. (A) Tectonic domain maps for the Alaskan and Canadian Cordillera with the location of the seismic-refl ection (red lines) and refraction (thick black lines) profi les used in the interpretations. Refl ection and refraction lines not incorporated in these composite profi les are shown by narrow gray and thick light-gray lines. Faults are indicated by solid and dashed thin black lines. (B–D) Composite interpretations and seismic models constructed for the three corridors. The primary tectonic domains crossed by the transect are indicated by the bar strip above each interpretation. Stippling above the crustal décollements indicates the complexity and uncertainty associated with the upthrust crust. In all of the panels, vertical exaggeration is 1:1. Direction headings note changes in the general orientation of the profi le. In the interpretation panels, solid navy lines indicate the interpreted location of wide-angle refl ectors. In the refl ection panels, thin red lines represent interpreted major refl ections, fabrics, and faults. The composite P-wave velocity model panels are presented using a common color scale. Velocities are also shown using numbers (km/s) and thin, dashed contour lines. The black lines represent interpreted wide-angle refl ector locations. The primary sources for the individual components of the compilation are noted below each panel. The red dashed line locates the modeled megathrust earthquake interface that represents the current plate boundary. For the southern Canadian Cordillera corridor (D), the blue dashed lines indicate boundaries determined by coincident teleseismic studies. Terrane abbreviations: A—Angayucham; AX—Alexander; BR—Bridge River; CA—Cassiar; CD-MT—Cadwallader-Methow; CC—Cache Creek; CF—Coldfoot; CH—Chugach; CR—Crescent; HA—Harrison; KO-YT—Kootenay-Yukon-Tanana; M—Manley; L—Livengood; MO—Monashee; NF—North Fork; NS—Nisling; OL—Olympic; PR—Pacifi c Rim; QN—Quesnellia; R—Ruby; SB—Spences Bridge; SM—Slide Mountain; T—Tozitna; W—Windy–Maclaren–Aurora Peak; WR—Wrangellia; Y—Yakutat. Other abbreviations: AW—accretionary wedge; C and E—refl ective bands; QCT—Queen Charlotte terrace; R/WAR—refraction/wide-angle refl ection; SC—Southern Cordillera; SCoRE—Southern Cordillera Refraction Experiment; SHIPS—Seismic Hazards in Puget Sound; SLF—Slocan Lake fault; SNORE—SNORCLE Refraction Experiment; VISP—Vancouver Island Seismic Profi le; WCF—West Coast fault.