folds, faults and other records of deformation

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Folds, Faults and Other Records of Deformation. Significance to CCS. Fundamental to trapping configuration Important for caprock integrity. Stress. Force per unit area Compression Tension (rare) Shearing. Or, principal compressive stress vertical. Brittle Versus Ductile Deformation. - PowerPoint PPT Presentation

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Folds, Faults and Other Records of Deformation

Folds, Faults and Other Records of Deformation

1Significance to CCSFundamental to trapping configurationImportant for caprock integrityStressForce per unit areaCompressionTension (rare)Shearing3

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Or, principal compressivestress vertical6Brittle Versus Ductile DeformationBrittle: material fractures (breaks)

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8Brittle Versus Ductile DeformationBrittle: material fractures (breaks)Ductile: plastic deformation, no fractures

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Folded gneiss and marble10Brittle Versus Ductile DeformationBrittle: material fractures (breaks)Ductile: plastic deformation, no fracturesBrittle favored by:

11Brittle Versus Ductile DeformationBrittle: material fractures (breaks)Ductile: plastic deformation, no fracturesBrittle favored by: low temperatures

12Brittle Versus Ductile DeformationBrittle: material fractures (breaks)Ductile: plastic deformation, no fracturesBrittle favored by: low temperatureslow confining pressures

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UndeformedLow confining pressureHigh confiningpressure14Brittle Versus Ductile DeformationBrittle: material fractures (breaks)Ductile: plastic deformation, no fracturesBrittle favored by: low temperatureslow confining pressureshigh strain ratesRock type

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Brittle diabase, ductile marble16Mapping Geologic StructuresStrikeDip

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19Mapping Geologic StructuresStrikeDipConstructing cross sections

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22FoldsBending of rocks, often as a result of compression

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Anticlines and Synclines24

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Raplee anticline and San Juan river, Utah27

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29Limbs, axial planes, fold axes

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Plunge31

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Plunging folds near Harrisburg, PA35

Plunging folds near Harrisburg, PA36

Plunging anticline, SW Montana37

Symmetrical, Asymmetrical, OverturnedLimbs of equal lengthLimbs of unequal length38

Overturned (almost?) anticline39Structural domes and basins

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44Faults and JointsFractures in rock45JointsNo visible displacementTypesUnloading (exfoliation)

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Unloading joint, Yosemite NP, CA47JointsNo visible displacementTypesUnloading (exfoliation)Cooling joints

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Devils Postpile, CA49

Devils Tower, WY50JointsNo visible displacementTypesUnloading (exfoliation)Cooling jointsRegional (tectonic) joints

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Joints in Navajo Sandstone, Arches NP, UT52FaultsVisible displacementHanging wall and footwall

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56FaultsVisible displacementHanging wall and footwallDip-slip faultsNormal57

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Normal fault, UT60FaultsVisible displacementHanging wall and footwallDip-slip faultsNormalReverse

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63FaultsVisible displacementHanging wall and footwallDip-slip faultsNormalReverseThrust

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Thrust: reverse motion with fault plane dipping