Lecture 5

36 231 2
Lecture 5

Đang tải... (xem toàn văn)

Tài liệu hạn chế xem trước, để xem đầy đủ mời bạn chọn Tải xuống

Thông tin tài liệu

1 Structural Geology: Deformation and Mountain Building Tectonic Stresses  Large Scale Strain of the Crust - Geologic Structures Crust: Rigid, Thin • Inner core: Solid iron • Outer core: Liquid iron, convecting (magnetic field) • Mantle (Asthenosphere) : Solid iron-magnesium silicate, plastic, convecting • Crust (Lithosphere): Rigid, thin 5-30km Mantle: Plastic, Convecting Tectonics and Structural Geology Tectonic Stresses resulting from Internal Energy (heat driving convection) Strains (deforms) the Mantle and Crust Bends Rocks ductile strain (Folds) •Breaks Rock •brittle strain (Joints) •Moves large blocks •Faults Releases energy Earthquakes Folds and Faults (Palmdale, Ca) Kaynasli, Turkey Stresses at Plate Boundaries • Divergent (Tensional) | • Convergent (Compressional) | • Transform (Shear) e.g., Pacific NW Geological Structures • Different stresses result in various forms of strain (geologic structures) • Folds (compressive stresses may cause ductile strain) • Faults (Any type of stress may cause brittle strain The type of fault depends on the type of stress) Geological Structures • Fault: a discontinuity surface across which there has been shear displacement • Hangingwall: the wall and body of rock above an inclined fault • Footwall: the wall and body of rock beneath an inclined fault 10 Geological Structures • Normal Fault: hanging wall moved downwards compared to the footwall • Reverse Fault: hanging wall moved upwards compared to the footwall • Thrust fault: low angle reverse fault 22 23 Brittle Strain  Joints • When shallow crust is strained rocks tend to exhibit brittle strain 24 Sheet Joints 25 Defining Fault Orientation • Strike of fault plane parallels the • fault trace • fault scarp • Direction of Dip of the fault plane indicates the Hanging wall block 26 Fault: • Movement occurring along a discontinuity • Brittle strain and subsequent movement as a result of stress • Fault terminology 27 Faults • Fault: When movement occurs along a discontinuity • Fault type depends on the type of stress 28 Normal Faults 29 Normal Faults, Horsts and Grabens 30 Horsts and Grabens • Older Rocks are exposed along the ridges formed by the horsts Horst Horst Graben Graben • Younger rocks lie beneath the grabens • Sediment fills in the linear valleys 31 Nevada • “Washboard topography” is the result of Horsts and Grabens • A.k.a, Basin and Range • E.g., Humbolt Range • E.g., Death Valley (Graben) 32 Horst and Graben, Nevada Horst Graben Humboldt Range, Northern Nevada 33 Horst and Graben, Nevada Horst Graben Humboldt Range, Northern Nevada 34 Reverse and Thrust Faults • Compressive stress causes the hanging wall to move upward relative to the foot wall  Reverse Fault • At convergent plate boundaries ancient rocks can be thrust over younger rocks  Thrust Fault 35 Thrust Fault: Glacier NP, Montana Old Younger 36 Strike Slip Faults • Physiographic Features

Ngày đăng: 29/11/2016, 23:31

Từ khóa liên quan

Mục lục

  • Structural Geology: Deformation and Mountain Building

  • Tectonic Stresses  Large Scale Strain of the Crust - Geologic Structures

  • Tectonics and Structural Geology

  • PowerPoint Presentation

  • Folds and Faults (Palmdale, Ca)

  • Kaynasli, Turkey

  • Stresses at Plate Boundaries

  • Geological Structures

  • Slide 9

  • Slide 10

  • Slide 11

  • Stikes and Dips are used to identify geologic structures

  • Strike and Dip

  • Slide 14

  • Anticline (fold)

  • Syncline (fold)

  • Slide 17

  • Plunging Anticline

  • Fold Terminology

  • Plunging Anticline, Colorado

  • Domes and Basins

  • Slide 22

  • Brittle Strain  Joints

  • Sheet Joints

  • Defining Fault Orientation

  • Fault:

  • Faults

  • Normal Faults

  • Normal Faults, Horsts and Grabens

  • Horsts and Grabens

  • Nevada

  • Horst and Graben, Nevada

  • Slide 33

  • Reverse and Thrust Faults

  • Thrust Fault: Glacier NP, Montana

  • Strike Slip Faults

Tài liệu cùng người dùng

  • Đang cập nhật ...

Tài liệu liên quan