Folds and Faults. Tectonic Plates Types of Differential Stress 123.
Faults, Folds, and Landscapes. Objectives Introduce basic terminology used in describing rock...
-
Upload
reginald-rose -
Category
Documents
-
view
244 -
download
0
Transcript of Faults, Folds, and Landscapes. Objectives Introduce basic terminology used in describing rock...
![Page 1: Faults, Folds, and Landscapes. Objectives Introduce basic terminology used in describing rock structure Distinguish between types of fault movements and.](https://reader034.fdocuments.net/reader034/viewer/2022051401/56649ea95503460f94bacbac/html5/thumbnails/1.jpg)
Faults, Folds, and Landscapes
![Page 2: Faults, Folds, and Landscapes. Objectives Introduce basic terminology used in describing rock structure Distinguish between types of fault movements and.](https://reader034.fdocuments.net/reader034/viewer/2022051401/56649ea95503460f94bacbac/html5/thumbnails/2.jpg)
Objectives
• Introduce basic terminology used in describing rock structure
• Distinguish between types of fault movements and the landforms they produce
• Discuss the folding of rocks and relate it to the landforms produced
• Call attention to occurrence of regional deformation of the crust, in addition to more local faults and folds
![Page 3: Faults, Folds, and Landscapes. Objectives Introduce basic terminology used in describing rock structure Distinguish between types of fault movements and.](https://reader034.fdocuments.net/reader034/viewer/2022051401/56649ea95503460f94bacbac/html5/thumbnails/3.jpg)
Terminology of Structure
• Strike– Line representing the
intersection of a planar feature with a horizontal plane
• Dip– Angle of a tilted bed
relative to a horizontal plane
![Page 4: Faults, Folds, and Landscapes. Objectives Introduce basic terminology used in describing rock structure Distinguish between types of fault movements and.](https://reader034.fdocuments.net/reader034/viewer/2022051401/56649ea95503460f94bacbac/html5/thumbnails/4.jpg)
Fault Terminology• Fault– Fracture in crustal rock
involving displacement of one side of the facture with respect to the other
• Joint– Fracture in the earth’s crust,
but with no displacement of rock bodies
An aerial view of the San Andreas fault in the Carrizo Plain, Central California. © USGShttp://pubs.usgs.gov/gip/earthq1/how.html
![Page 5: Faults, Folds, and Landscapes. Objectives Introduce basic terminology used in describing rock structure Distinguish between types of fault movements and.](https://reader034.fdocuments.net/reader034/viewer/2022051401/56649ea95503460f94bacbac/html5/thumbnails/5.jpg)
Fault Terminology
• Hanging Wall– Block of rocks above
the fault line
• Footwall– Block of rocks below
the fault line Figure. Image of hanging wall and footwall. © USGS NPS
![Page 6: Faults, Folds, and Landscapes. Objectives Introduce basic terminology used in describing rock structure Distinguish between types of fault movements and.](https://reader034.fdocuments.net/reader034/viewer/2022051401/56649ea95503460f94bacbac/html5/thumbnails/6.jpg)
Compressional Faults
• Reverse fault• Hanging wall moves up relative
to the footwall• Fault plane angle >45°
![Page 7: Faults, Folds, and Landscapes. Objectives Introduce basic terminology used in describing rock structure Distinguish between types of fault movements and.](https://reader034.fdocuments.net/reader034/viewer/2022051401/56649ea95503460f94bacbac/html5/thumbnails/7.jpg)
Compressional Faults
• Thrust fault• Hanging
wall moves up relative to footwall• Fault plane
angle <45°
![Page 8: Faults, Folds, and Landscapes. Objectives Introduce basic terminology used in describing rock structure Distinguish between types of fault movements and.](https://reader034.fdocuments.net/reader034/viewer/2022051401/56649ea95503460f94bacbac/html5/thumbnails/8.jpg)
Tensional Fault
• Normal fault– Hanging wall moves down
relative to footwall– Produced by extensional
forces
![Page 9: Faults, Folds, and Landscapes. Objectives Introduce basic terminology used in describing rock structure Distinguish between types of fault movements and.](https://reader034.fdocuments.net/reader034/viewer/2022051401/56649ea95503460f94bacbac/html5/thumbnails/9.jpg)
Tensional Fault
![Page 10: Faults, Folds, and Landscapes. Objectives Introduce basic terminology used in describing rock structure Distinguish between types of fault movements and.](https://reader034.fdocuments.net/reader034/viewer/2022051401/56649ea95503460f94bacbac/html5/thumbnails/10.jpg)
Tensional Fault Landscapes
• Basin and Range– A series of mountains
(horsts) and valleys (grabens)
• Rift Valleys– Long, narrow band of
downdropped block caused by plates being pulled apart (tension) and
![Page 11: Faults, Folds, and Landscapes. Objectives Introduce basic terminology used in describing rock structure Distinguish between types of fault movements and.](https://reader034.fdocuments.net/reader034/viewer/2022051401/56649ea95503460f94bacbac/html5/thumbnails/11.jpg)
Transverse Fault
• Strike-slip fault– Blocks of rock slide past
one another– Horizontal displacement
![Page 12: Faults, Folds, and Landscapes. Objectives Introduce basic terminology used in describing rock structure Distinguish between types of fault movements and.](https://reader034.fdocuments.net/reader034/viewer/2022051401/56649ea95503460f94bacbac/html5/thumbnails/12.jpg)
Fold Formation
• Folding– Compressional force is applied to rocks– Rocks respond by bending before fracturing
![Page 13: Faults, Folds, and Landscapes. Objectives Introduce basic terminology used in describing rock structure Distinguish between types of fault movements and.](https://reader034.fdocuments.net/reader034/viewer/2022051401/56649ea95503460f94bacbac/html5/thumbnails/13.jpg)
Fold Structures
• Anticlines– Archlike fold with limbs
dipping away[Insert 34.12 - anticline]
![Page 14: Faults, Folds, and Landscapes. Objectives Introduce basic terminology used in describing rock structure Distinguish between types of fault movements and.](https://reader034.fdocuments.net/reader034/viewer/2022051401/56649ea95503460f94bacbac/html5/thumbnails/14.jpg)
Fold Structures
• Synclines– Troughlike
fold with limbs dipping toward the axes
![Page 15: Faults, Folds, and Landscapes. Objectives Introduce basic terminology used in describing rock structure Distinguish between types of fault movements and.](https://reader034.fdocuments.net/reader034/viewer/2022051401/56649ea95503460f94bacbac/html5/thumbnails/15.jpg)
Anticlines
• Erosion removes upper portion of anticline• Limbs dip toward the center of fold• Older rocks are near center and becomes
progressively younger with distance
![Page 16: Faults, Folds, and Landscapes. Objectives Introduce basic terminology used in describing rock structure Distinguish between types of fault movements and.](https://reader034.fdocuments.net/reader034/viewer/2022051401/56649ea95503460f94bacbac/html5/thumbnails/16.jpg)
Synclines• Erosion removes
upper portion of anticline
• Limbs dip toward the center of fold
• Older rocks are near center and becomes progressively younger with distance
![Page 17: Faults, Folds, and Landscapes. Objectives Introduce basic terminology used in describing rock structure Distinguish between types of fault movements and.](https://reader034.fdocuments.net/reader034/viewer/2022051401/56649ea95503460f94bacbac/html5/thumbnails/17.jpg)
Plunging Folds and Associated Landscapes
• Anticlines and synclines often plunge; axes dip