GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults...
-
Upload
dwain-townsend -
Category
Documents
-
view
223 -
download
0
description
Transcript of GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults...
![Page 1: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/1.jpg)
GLG310 Structural Geology
![Page 2: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/2.jpg)
May 6, 2023 GLG310 Structural Geology
Description of faults
Normal Thrust/reverse Strike-slipHorizontal stretch
>1 <1 >1 in one direction and < 1 in another
Crustal thickness
Thin Thicken No change
Regional elevation
Usually lower Usually higher No change
Regional character
Rifting, Mid Ocean ridges, gravitational collapse, local accommodation along strike-slip faults
Subduction zones/accretionary prisms, continent/continent collision, back arc fold thrust belts, local accommodation along strike-slip faults
Transforms, oblique convergence (i.e., Sumatra), continental collision, Transfers in other fault systems
Issues Detachments, Listric, rotation, rifted margins
Layered rocks, reverse versus thrust
Transforms, bends and stepovers
![Page 3: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/3.jpg)
Normal faults
http://www.tectonics.caltech.edu/taiwan/regional.htm
• Put younger over older
• Often in “rifts”
Normal faults in Iran (http://www.imaggeo.net/view/807)
![Page 4: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/4.jpg)
Global Spreading Ridges from http://topex.ucsd.edu/marine_topo/globe.html
![Page 5: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/5.jpg)
![Page 6: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/6.jpg)
May 6, 2023 GLG310 Structural Geology
![Page 7: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/7.jpg)
![Page 8: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/8.jpg)
Comparative “riftology”
East African Rift
Gulf of California
Eastern North America
![Page 9: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/9.jpg)
T. Rooney
Significant variation in fault array geometry along the system
![Page 10: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/10.jpg)
Development of extensional systems
![Page 11: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/11.jpg)
Clay cake on a rubber sheet: analogy for brittle upper crust (clay) over ductile and uniformly extending lower crust
![Page 12: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/12.jpg)
horstgraben
Upper part of system has steep, Andersonian dips, but lower portion has a detachment (salt horizon or other ductile level) into which the faults “root”
The down dip curving or shallowing of dip is “listric”
![Page 13: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/13.jpg)
http://archives.datapages.com/data/bulletns/2009/04apr/BLTN08117/BLTN08117.HTM
Experimental development of a normal fault system
![Page 14: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/14.jpg)
1983 M7.3 Borah Peak Earthquake
Classic study by Stein and Barrientos
![Page 15: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/15.jpg)
![Page 16: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/16.jpg)
![Page 17: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/17.jpg)
![Page 18: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/18.jpg)
![Page 19: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/19.jpg)
Borah Peak earthquakeDisplacements and long term offset
![Page 20: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/20.jpg)
Top map showings discontinuous rupture trace and several zones of complex faulting, such as near Arentson Gulch, West Spring, and Elkhorn Creek. Displacement along strike shows greatest vertical offset near Rock Creek (where the highest peak is also found in the footwall), overlapping offsets where decreasing displacement on one fault is compensated for by increasing displacement on another fault (Arentson Gulch to West Splay Junction), and a broadly bow-shaped displacement pattern (dashed line) along this succession of fault traces that is similar to the pattern seen on individual normal . Double arrows depict orientation of striae on the fault plane and indicate oblique dip-slip on this fault. The location of the levelling line survey runs approximately perpendicular to the rupture trace. Modified after Crone and Machette (1984). --Burbank and Anderson
![Page 21: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/21.jpg)
Normal arrays, their displacement profiles, and relays
![Page 22: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/22.jpg)
May 6, 2023 GLG310 Structural Geology
![Page 23: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/23.jpg)
Burbank and Anderson
![Page 24: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/24.jpg)
Burbank and Anderson
![Page 25: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/25.jpg)
Sedimentaryfills
Rift basin architecture
Sedimentary Rift BasinsSedimentary Rift Basins
What are rift basins and why are they important?
Depositional environments
Process
- elongate crustal depressions- variety of tectonic settings- economically important
Project Focus: Inverse problem – extract process from structure
and fills
3Withjack and Schlische, 2002
Faunal Evolution
?J. Gurche
DiMaggio
![Page 26: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/26.jpg)
26 October 2004 GLG310 Structural Geology
Normal faults
![Page 27: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/27.jpg)
Rotating faults become less well oriented and a second set forms
![Page 28: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/28.jpg)
Rotating faults become less well oriented and a second set forms
http://blog.summitkwan.com/?p=182
![Page 29: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/29.jpg)
Normal fault geometries
![Page 30: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/30.jpg)
May 6, 2023 GLG310 Structural Geology
Idealized diagram of a metamorphic core complex or detachment system--these are common in Arizona
![Page 31: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/31.jpg)
26 October 2004 GLG310 Structural Geology
Development of extensional systems
Normal faults
![Page 32: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/32.jpg)
26 October 2004 GLG310 Structural Geology
Inversion tectonics and fault reactivation
![Page 33: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/33.jpg)
May 6, 2023 GLG310 Structural Geology
Description of faults
Normal Thrust/reverse Strike-slipHorizontal stretch
>1 <1 >1 in one direction and < 1 in another
Crustal thickness
Thin Thicken No change
Regional elevation
Usually lower Usually higher No change
Regional character
Rifting, Mid Ocean ridges, gravitational collapse, local accommodation along strike-slip faults
Subduction zones/accretionary prisms, continent/continent collision, back arc fold thrust belts, local accommodation along strike-slip faults
Transforms, oblique convergence (i.e., Sumatra), continental collision, Transfers in other fault systems
Issues Detachments, Listric, rotation, rifted margins
Layered rocks, reverse versus thrust
Transforms, bends and stepovers
![Page 34: GLG310 Structural Geology. 24 February 2016GLG310 Structural Geology Description of faults NormalThrust/reverseStrike-slip Horizontal stretch 111 in.](https://reader035.fdocuments.in/reader035/viewer/2022081512/5a4d1b877f8b9ab0599bd38f/html5/thumbnails/34.jpg)
May 6, 2023 GLG310 Structural Geology
Description of faults
Normal Thrust/reverse Strike-slipHorizontal stretch
>1 <1 >1 in one direction and < 1 in another
Crustal thickness
Thin Thicken No change
Regional elevation
Usually lower Usually higher No change
Regional character
Rifting, Mid Ocean ridges, gravitational collapse, local accommodation along strike-slip faults
Subduction zones/accretionary prisms, continent/continent collision, back arc fold thrust belts, local accommodation along strike-slip faults
Transforms, oblique convergence (i.e., Sumatra), continental collision, Transfers in other fault systems
Issues Detachments, Listric, rotation, rifted margins
Layered rocks, reverse versus thrust
Transforms, bends and stepovers