Outline: Normal Fault Systems and Kinematics

Outline: Outline: Normal Fault Systems and Normal Fault Systems and

KinematicsKinematics• Planar Faults and Block Rotation

• Detachment Faulting

• Fault Linkage

• Kinematics of Normal Faulting

Development of Continental Rift into Ocean Basin

Upwelling of hot mantleThins, weakens, and cracks the lithosphere

Development of Continental Rift into Ocean BasinRift ValleyEarly graben formation prior to continental splitting. This stage may be associated with domal uplift caused by uprise of hot upper mantle material - uplift may be connected with underlying mantle hotspots.

Development of Continental Rift into Ocean BasinYoung ocean basinLast about 50 my after the onset of seafloor spreading, while the thermal effects are still dominant.

Characterized by rapid regional subsidence of the outer shelf and slope, but some graben formation may persist. Example: Red Sea.

Development of Continental Rift into Ocean Basin

Mature Ocean basinSubdued regional subsidence may continue. Example: most of the present Atlantic continental margins.

East African Rift SegmentationEast African Rift Segmentation

9 mm/a (GPS)

16 mm/a (GPS)

Basin and Range Normal Fault BlocksBasin and Range Normal Fault Blocks

Rio Grande Rio Grande RiftRift

Segmentation Segmentation

Death ValleyDeath ValleyFault Zone Fault Zone

Fault StepoverFault Stepover

Closeup of StepoverCloseup of Stepover

Planar Normal Faults and Block Planar Normal Faults and Block

RotationRotation

Planar Normal Faults and Block Planar Normal Faults and Block

RotationRotation

Domino Block ExampleDomino Block Example

Domino Block ExampleDomino Block Example

Detachment FaultDetachment Fault

Detachment FaultDetachment Fault

Detachment FaultDetachment Fault

Soft-Linked SystemsSoft-Linked Systems

Kinematics of Normal FaultingKinematics of Normal Faulting

• Domino, Bookshelf-Style Normal Faulting

• Listric Normal Faulting with Reverse Drag

• Imbricate Listric Normal Faulting

• Inversion

Domino-Style Normal FaultingDomino-Style Normal Faulting

Domino-Style Normal Faulting (bookshelf Domino-Style Normal Faulting (bookshelf

faulting)faulting)

Occurs above Detachment faultsOccurs above Detachment faults

Listric-Planar Normal Fault Listric-Planar Normal Fault

SystemSystem

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Listric-Planar Normal Fault Listric-Planar Normal Fault

SystemSystem

L

Listric Normal Faulting with Reverse Listric Normal Faulting with Reverse

DragDrag

Listric Normal Faulting with RolloverListric Normal Faulting with Rollover

Occurs due to space problem with curved Occurs due to space problem with curved

detachmentdetachment

Imbricate Listric Normal FaultingImbricate Listric Normal Faulting

Synthetic faults also accommodate collapse of HW blockSynthetic faults also accommodate collapse of HW block

Imbricate Listric Normal FaultingImbricate Listric Normal Faulting

““Meatslices common in large displacement systemsMeatslices common in large displacement systems

InversionInversion

• Normal faulting

• Syn-tectonic deposition of B

• Post-tectonic deposition of C

InversionInversion

• Normal faulting

• Syn-tectonic deposition of B

• Post-tectonic deposition of C

• Thrust faulting

• Deformation of B and folding of C

ReferencesReferences

Slides 1, 20, 21Slides 1, 20, 21Twiss, R. J. and E. M. Moores, Structural Geology, W. H. Freeman & Co., New York, 532 p., Twiss, R. J. and E. M. Moores, Structural Geology, W. H. Freeman & Co., New York, 532 p., 1992.1992.

Slides 3-6Slides 3-6http://earth.leeds.ac.uk/faults/normal/domino.htm

Slides 7-9Slides 7-9http://earth.leeds.ac.uk/faults/normal/detachment1.htm

Slide 10Slide 10http://earth.leeds.ac.uk/faults/soft/softnormal.htm

Slides 12-19Slides 12-19Davis. G. H. and S. J. Reynolds, Structural Geology of Rocks and Regions, 2nd ed., John Davis. G. H. and S. J. Reynolds, Structural Geology of Rocks and Regions, 2nd ed., John Wiley & Sons, New York, 776 p., 1996.Wiley & Sons, New York, 776 p., 1996.