1. Payne and McClelland, 2006
A Newly Recognized Shear Zone in Western Idaho:
Implications for Late Cretaceous Thick and
Thin-Skinned Shortening in the Rocky Mountain Foreland
100
Km
0
N
C
C’ C C’
Jonathan D. Payne, Geologist, Devon Energy, Oklahoma City, OK 73102
Dr. William C. McClelland, Geological Sciences Dept., University of Idaho, Moscow, ID 83844

2. Payne and McClelland, 2006
Acknowledgements:
• NSF Grant EAR 701-29685 to McClelland
• GSA Student Research Grant 01-46732 to Payne
Payne and McClelland, 2006

3. Payne and McClelland, 2006
• Many Cretaceous shear
zones parallel to orogen
• How to they relate?
• Timing needed to constrain
models
Payne and McClelland, 2006

4. Payne and McClelland, 2006
• WISZ is a crustal scale
boundary
• Wallowa separated from
N. America by Salmon
River Belt and Western
Idaho Shear Zone
Payne and McClelland, 2006

5. Payne and McClelland, 2006
OR
Structurally Controlled
Geometry
TRUNCATION
Original Margin
Geometry
50 50 50
RIGHT-OBLIQUE
CONVERGENCE
HEAD ON
COLLISION
KINEMATIC ALTERNATIVES FOR THE BEND
Payne and McClelland, 2006

6. Payne and McClelland, 2006

7. Payne and McClelland, 2006
01JP313NW SE
01JP367
5 mm
SW NE
5 mm
01JP451SW NE
5 cm
NW SE01JP381
TOP TO THE SW
LEFT LATERAL

8. Payne and McClelland, 2006

9. Payne and McClelland, 2006
100 µm
85.4 ± 2.6
81.5 ± 2.1
89.4 ± 4.5
88.6 ± 2.3
90.4 ± 3.6
88.5 ± 4.3
1) 90.5 ± 1.4 Ma
87.7 ± 3.0 90.0 ± 2.1
90.3 ± 2.097.0 ± 2.5
92.2 ± 2.3
84.5 ± 1.8
1782 ± 30
90.1 ± 2.1
2) 88.6 ± 2.2 Ma

10. Payne and McClelland, 2006

11. Payne and McClelland, 2006
3) 73.5 ± 1.4 Ma
71.6 ± 3.4
72.9 ± 2.5
72.2 ± 2.3
70.4 ± 3.3
70.2 ± 2.6
74.5 ± 2.2
74.6 ± 3.0
73.8 ± 2.4
75.3 ± 2.1
72.0 ± 2.1
71.7 ± 2.3
73.9 ± 2.7
71.9 ± 2.4
100 µm
4) 72.0 ± 1.6 Ma

12. Payne and McClelland, 2006
72.0 Ma
73.5 Ma
90.5 Ma
88.6 Ma

13. Payne and McClelland, 2006
157.0 Ma
72.0 Ma
73.5 Ma
90.5 Ma
88.6 Ma

14. Payne and McClelland, 2006
157.0 Ma
113.2 Ma
72.0 Ma
73.5 Ma
90.5 Ma
88.6 Ma

15. Payne and McClelland, 2006
157.0 Ma
113.2 Ma
72.0 Ma
87.0 Ma
73.5 Ma
90.5 Ma
88.6 Ma

16. Payne and McClelland, 2006
Conclusions:
• Bend in boundary due to
TRUNCATION of the WISZ
(N-S) by the OSZ (NW)
• OSZ records reverse (and
left-lateral?) displacement
• OSZ underway by 88 Ma,
ongoing at 72 Ma

17. Payne and McClelland, 2006
100
Km
0
Pz-Mz
pCs
met rx
Archean
Qs
CANADA
TKg
Ts
U.S.A.
N
C
C’
A
A’
B’
B

18. Payne and McClelland, 2006
Linking thick- and thin-skinned deformation
(Late K – Early T)
• Orofino Shear Zone connects thick-
skinned displacements N-to-S
• OSZ coincident with N-to-S increase in
depth to basal detachment
• Change in detachment depth can be
accommodated by SW-dipping Basement
Ramp

19. Payne and McClelland, 2006
Timing of thick- and thin-skinned deformation
• U.S. Rockies:
Laramide (thick) and Sevier (thin) overlap in time
(Oldow et al, 1989)
• Canadian Rockies:
Shuswap Complex (thick) and Foreland F & T (thin)
overlap in time
(Cook et al, 1992)
• Shuswap, OSZ, Laramide and Foreland F & T have
similar timing
Age equivalence requires mechanical linkage

20. Payne and McClelland, 2006
A A’
B
B’
Central Cordillera
C
C’

21. Payne and McClelland, 2006
km
0
10
20
30
km
0 30 60 km
Mesozoic
Paleozoic
Proterozoicmetamorphic
tectonites
K-T Plutons
A’A
0
10
20
30
modified after Norris and Bally, 1972
Archean

22. Payne and McClelland, 2006
A A’
B
B’
Central Cordillera
C
C’

23. Payne and McClelland, 2006
0 30 60km
B
km
0
10
20
30
50
40
km
B’
0
10
20
30
50
40
MOHO MOHO
modified after Bally and Snelson, 1980
Mesozoic
Paleozoic
ProterozoicTertiary
Archean

24. Payne and McClelland, 2006
A A’
B
B’
Central Cordillera
C
C’

25. Payne and McClelland, 2006
C C’
SW NE
Accreted Terranes
Proterozoic
Metamorphic
Detached Basement
OSZ
WISZ
Present day
Exposure

26. Payne and McClelland, 2006
100
Km
0
Pz-Mz
pCs
met rx
Archean
Qs
CANADA
TKg
Ts
U.S.A.
N
C
C’
Central Cordillera
Mid Cretaceous
(90 Ma)

27. Payne and McClelland, 2006
Paleozoic
Proterozoic
Metamorphic
Detached Basement
C C’
SW NE
Central Cordillera
Mid Cretaceous
(90 Ma)
WISZ
0 km
10
20
0 km
10
20

28. Payne and McClelland, 2006
100
Km
0
Pz-Mz
pCs
met rx
Archean
Qs
CANADA
TKg
Ts
U.S.A.
N
C
C’
Central Cordillera
Late Cretaceous
(65 Ma)

29. Payne and McClelland, 2006
Paleozoic
Proterozoic
Metamorphic
Detached Basement
C C’
SW NE
Central Cordillera
Latest Cretaceous
(pre-65 Ma)
WISZ
OSZ
0 km
10
20
0 km
10
20

30. Payne and McClelland, 2006
Paleozoic
Proterozoic
Metamorphic
Detached Basement
C C’
SW NE
OSZ
WISZ
Exposure
Depth
Central Cordillera
Latest Cretaceous
(65 Ma)
0 km
10
20
0 km
10
20

31. Payne and McClelland, 2006
A A’
B
B’
Central Cordillera
C
C’

32. Payne and McClelland, 2006
A A’
B
B’
Central Cordillera
C
C’

33. Payne and McClelland, 2006
A Newly Recognized Shear Zone in Western Idaho:
Implications for Late Cretaceous Thick and
Thin-Skinned Shortening in the Rocky Mountain Foreland
Jonathan D. Payne, Geologist, Devon Energy, Oklahoma City, OK 73102
Dr. William C. McClelland, Geological Sciences Dept., University of Idaho, Moscow, ID 83844
100
Km
0
N
C
C’ C C’

34. Payne and McClelland, 2006
• Structures in Wallowa and Salmon River Belt are pre-144 Ma
• Structures in Wallowa and Salmon River Belt are truncated by WISZ
Gray and Oldow, 2005

35. Payne and McClelland, 2006
• Structures in Wallowa and
SRB are pre-144 Ma
• WISZ was active from
≈ 118 – 90 Ma
• WISZ records post-accretion
displacement

36. Payne and McClelland, 2006
Where is the northern counterpart to the WISZ?

37. Payne and McClelland, 2006
100
Km
0
Pz-Mz
pCs
met rx
Archean
Qs
CANADA
TKg
Ts
U.S.A.
N
C
C’
A
A’
B’
B

38. Payne and McClelland, 2006
Western Idaho Shear Zone:
• Intra-arc transpressional
shear zone (correlates with
Western Nevada Shear Zone)
• Uncertain transcurrent shear
sense
Orofino Shear Zone:
• Truncates Western Idaho
Shear Zone
• Age Equivalent and may
correlate with Coast Shear
Zone
Latest K – Eocene Boundary
Parallel Displacement:
• Cannot be accommodated by
WISZ or WNSZ
• Possible link between SCSZ
and CSZ