Brittle Deformation FAULT is a structural plane along which considerable amount of movement is visible. 1
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Fault Fault zone Shear zone 6
Three basic criteria: Criteria for the Recognition of Faults 1. Fault rocks 2. Effects on geological and stratigraphical units 3. Effects on topography (physiographic elements) 1. Fault rocks Cataclastic Rocks, Fault Breccia, Mylonite Non-cohesive cataclasites Cataclastic fault rocks Cohesive cataclasites Mylonitic fault rocks 7
Cataclastic rocks: (A) Megabreccia; (B) cataclasite 8
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Cataclasite Mylonite 10
Structures on the fault plane 11
oluklar sırtlar groove ridges Striations/fault lines çizikler 12
Fault steps Grooves and fault steps Prof.Dr.Kadir Dirik Ders Notları 13
Chatter marks Ridel fractures 14
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2- The effects on geological and stratigraphical units A Juxtaposition (Yanyana Gelme ) 18
B Ommision and Repetition of Strata (Eksik/Kayıp ve Bindirme/ Tekrarlanma Alanları) Kuyu karot Normal istif Tavan blok Kuyu karot Normal istif Tavan blok Kısalma miktarı Tekrarlayan birim Uzama miktarı Kaybolan / Eksik birim Ters Fay Normal Fay 19 19
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C Drag Folds (Sürüklenme /Sürüme Kıvrımları) D Rollover Anticlinal (Ters Sürüme Kıvrımı) 23
3- Effects on topography (physiographic elements) A Fault Scarp 24
B Fault Line Scarp Fay çizgisi Sarplığı Dayanımlı katman 25
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C Triangular facets and alluvial fans (Fay zonunda görülen üçgen yüzeyler ve sıralı birikinti konileri) () 28
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CLASSIFICATION OF FAULTS Basically two criteria are used for the classification of faults: (1) Position of the fault plane; (2) Slip direction. (1) Classification Based on Position of the fault plane; Inclined Faults Vertical Faults 33
(2) Classification based on Slip direction. 34
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ANDERSON classification Based on the principal stress directions Normal Faults Reverse/thrust faults Strike-slip faults 36
Faults and Principal Stress Directions http://www.see.leeds.ac.uk/structure/faults/stress/stress.gif 37
AA- anticlinal axis MF- master fault NF- normal fault OF- extensional joint P- splay fault PDZ- main displacement zone R- sintetic Ridel fracture R - antitetic Ridel fracture RF- reverse fault SA- synclinal axis TF- thrust fault 38
Normal Fault Dip amount of fault plane: > 45 o, <90 o in general: 60 o 39
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Reverse Fault Dip amount of fault plane: > 45 o, Low angle reverse fault: ~30 o named as Thrust fault 42
Thrust Fault Nappe 43
Strike-slip fault Movement vector is paralel to the strike of fault and perpendicular to the dip of fault plane. 44
Prof.Dr.Kadir Dirik Ders Notları 45
www.geology.cwu.edu/facstaff/charlier/courses/g360/ppt/lecture18_strikeslipfault1.ppt Prof.Dr.Kadir Dirik Ders Notları 46
Oblique-slip fault Movement vector is oblique to the strike of fault. 47
Rotational (Pivotal/Burulma) Faults 48
JOINT is a fracture/structural plane along which no considerable amount of movement is visible. Types of Joint 1- Tectonic joints 2- Non-tectonic joints 1- Tectonic Joints (a) Extensional joints; (b) Shear joints; (c) Tension gashes 49
(a) Extensional joints 50
(a) Extensional joints Orthogonal joints 51
If the space of extensional joints are filled by calcite, quartz or some other minerals, they are named as vein. 52
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(b) Shear joints 55
(c) Tension gashes Tension gashes are a special type of vein that can form rather spectacular patterns 56
http://www.see.leeds.ac.uk/structure/folds 57
http://www.see.leeds.ac.uk/structure/folds 58
2- Non-tectonic joints (a) Mudcracks 59
(b) Cooling joints (columnar joints) 60
(b) Sheet joints Formed by pressure release 61
UNCONFORMITIES Representing times of nondeposition, erosion or both Paraconformity Disconformity Angular unconformity Nonconformity 62
DISCONFORMITY Uplift Deposition Disconcormity Uplift and erosion (Monroe&Wicander, 2005) Deposition 63
ANGULAR UNCONFORMITY Uplift Deposition Angular unconformity (Monroe&Wicander, 2005) Erosion Uplift and tilting Deposition 64
NONCONFORMITY Uplift Deposition Nonconformity Uplift and erosion of overlying sediments (Monroe&Wicander, 2005) Intrusion of magna 65
Prof.Dr.Kadir Dirik Ders Notları 66