Structural Geology

(GO 314 & 314L)

Welcome to structural geology! Structure is the aspect of geosciences that examines the products and processes of deformation within the Earth. As we explore deformation of Earth materials, we will integrate information and observations at a wide variety of scales – from bending and breaking atomic bonds during the deformation of a crystal lattice, to bending and breaking lithospheric plates during the creation of a mountain belt.

Because deformation is commonly a complex, three-dimensional process, learning to think and visualize in three dimensions is an important skill. We will spend quite a bit of time practicing and working on problems to enhance your ability to see in 3-D (and sometimes 4-D)! In addition, because structural features like faults, folds, etc., are geometric in nature, we can often predict their locations and spatial interactions from basic geometric constraints. Consequently, basic trigonometry is a powerful tool in structural geology. If you have not used trigonometry in a while, a quick review might be a good idea.

Another challenge in structural geology is the jargon. Like most aspects of geology, structure involves a lot of new terminology.  We will also refine the definitions of some words you may already know. For example, everyone knows what stress and strain mean, right? Right! … well … sort of… hmm… J .

Course Objectives:

After successful completion of this class and the accompanying lab, students will be able to:

  1. Accurately identify, describe, and interpret a wide variety of geologic structures, including various kinds of faults, folds, and fabric.
  2. Quantitatively analyze orientation data using stereographic projection, orthographic projection, and other techniques.
  3. Reconstruct regional structural development from information on a geologic map.
  4. Produce geologically reasonable and geometrically constrained cross sections.
  5. Quantitatively estimate strain.
  6. Predict the subsurface locations of structurally controlled features like ore deposits, petroleum accumulations, etc.

Evaluation and grading will be based on a combination of two midterm exams, a comprehensive final exam, and various weekly laboratory assignments. Structural geology is a challenging subject, but one that is also interesting and enjoyable. So, although you will work hard, don’t forget to have fun!

cheers,

 

C. J. Northrup

                Syllabus: Introduction to Structural Geology
                                           (GO 314 & 314L)

C. J. Northrup
office: MG 223B
phone: 426-1009
cjnorth@boisestate.edu
office hours: M & W, 9:30-11:30 (or by appointment)

Class Date            Topic                                             Reading

Jan.  19                 Introduction and Overview                                           Ch 1
       19L              Orientation Analysis of Planes (due 1/26)
        21                 Joints and Fractures                                                      Ch 7
        26                 Introduction to Faults                                                    Ch 8
        26L              Stereonets and Stereographic Projection (due 2/2)
        28                Normal Fault Systems                                                  Sec. 8.6.2
Feb.   2                Thrust Fault Systems                                                    Sec. 8.6.3
          2L              Analysis of Faults: Net-Slip (due 2/9)
          4                Strike-Slip Fault Systems                                             Sec. 8.6.4
          9                 Force, Traction, and Stress                                            Ch 3
          9L              Geologic Maps and Cross Sections (due 2/16
        11                Mohr Circle for Stress                                                   Sec. 3.8
        16                 Brittle Failure: Theory and Experimental Studies            Ch 6
        16L               Mohr Circle Analysis (due 2/23)
        18                 Brittle Failure: Mechanics                                               Ch 6
        23                  Introduction to Folds                                                      Ch 10
        23L               Review Session
        25                 Hour Exam 1
Mar.  2                  Description of Folds                                                      Ch 10
         2L                 Fold Analysis (due 3/9)
         4                   Kinematic Models of Folding                                         Ch 10
         9                   Deformational Fabric: Foliation and Lineation                 Ch 11
         9L                 Geologic Sequence of Events (due 3/16)
       11                   Ductile Shear Zones and Mylonites                                 Ch 12
       16                    Homogeneous Strain and the Strain Ellipse                       Ch 4
       16L                  Strain Measurement in Rocks (due 3/30)
       18                    Progressive, Coaxial and Noncoaxial Deformation             Ch 4
       23                    Spring Break
       23L                  Spring Break
       25                    Spring Break
       30                    Strain and the Formation of Ductile Structures
       30L                  Review Session
Apr. 1                    Hour Exam 2
         6                    GSA meeting (no class)
         6L                  GSA meeting (no class)
         8                    GSA meeting (no class)
       13                    Field exercise, Castle Rock (with Dr. Waag)
       13L                  Field exercise, Castle Rock
       15                    Stress-Strain Relationships: Rheology                                  Ch 5
       16-19               Field Trip to Northern Nevada (optional; can sign-up for additional credit)
       20                    Microstructural Geology: Deformation Mechanisms               Ch 9
       20L                  Structural Petrography (due 4/27)
       22                    Deformation, Metamorphism, and Time                                 Ch 13
       27                    Introduction to Plate Tectonics & Orogenic Systems              Ch 14
       27L                 Geologic Maps: Interpreting Regional History (due 5/4)
       29                    Examples of Collisional & Contractional Tectonics                  Ch 16
May 4                      Examples of Rifting & Extensional Tectonics                            Ch 15
         4L                  Plate Reconstructions, (due at end of lab)
         6                    a look back...

                    Comprehensive Final Exam: Wednesday, May 13, 3:30-5:30 pm

Please bring a ruler, protractor, drafting compass, and several colored pencils to lab sessions.
Grades will be determined from a combination of exams and lab assignments, using the following formula:

hour exam 1      15%
hour exam 2      15%
lab assignments 45%
final exam         25%
                     ———
           Total = 100%

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