Exploring Styles of Extension in the Gulf of California

• Given a cross-section of a rifted area, identify and explain various features and the processes responsible for producing these features
  
• Explain how seismic sections work, including the idea of two-way travel time. Recognize reflectors on a seismic line and use offset reflectors to draw in faults.
  
• Explain the differences in rifting and styles of faulting from south to north in the Gulf of California, east to west in the northern Gulf and through time.
  
• Synthesize the factors that influence rifting and explain how each contributes to styles of faulting
  
• Summarize the methods and types of data used to study rifting
  

1. An introduction to a variety of extensional styles

Introduction to Extensional Styles: an overview (PowerPoint 2007 (.pptx) 24.1MB Oct7 15) This presentation reviews 1) normal faults, 2) transtensional features 3) styles of rifting in continents and 4) various rifted margin types (20-45 minutes).

As part of this lecture, instructors may want to do the existing SERC activity: Evolution of Normal Fault Systems During Progressive Deformation

2. Seeing different styles of extension in seismic data from the Gulf of California

• Introduction to seismic data with in-class activites (60-90 minutes):
  
• Powerpoint: Introduction to Seismic Data and Rifting in the Gulf of CA (PowerPoint 2007 (.pptx) 30.6MB Oct7 15)
• In-class activity 1 handout In-class seismic activity 1 (Microsoft Word 1.8MB Sep11 15)
• In-class activity 2 handout In-class seismic activity 2 (Microsoft Word 2.1MB Sep11 15)
• Jigsaw lab activity (75-90 minutes): _{A "jigsaw" activity has students complete a project in 2 steps. In step 1, each group of students completes a different task to learn something specific and become an "expert" at that task or with that new knowledge. In step 2, new groups are formed, each with a different "expert" from step 1. They must complete a new task using the different skills learned in step 1.}
  
• Student version of the lab Seismic Lab Handout Student Version (Microsoft Word 2007 (.docx) 103kB Sep11 15)
• Instructor version of the lab with teaching suggestions
  Seismic Lab Handout Instructor Version -- private instructor-only file
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  Seismic Lab Handout Instructor Version

  
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• Seismic Images Seismic Images for Jigsaw Lab (Acrobat (PDF) 42.4MB Sep11 15). Note that this file has both the uninterpreted and interpreted lines. You may want to photocopy them first, cut the "answer" off and let students play with the uninterpreted line before showing them the published interpretation.
• Location Map (Microsoft Word 2007 (.docx) 881kB Oct7 15) of the 4 seismic profile lines used in the Jigsaw Lab
• A few wrap-up slides for this activity are found in the Introduction to Seismic Data Lecture ppt found above.

3. Wrap-up: see the Extension Wrap Up Lecture (PowerPoint 2007 (.pptx) 5.9MB Oct7 15) presentation on the different styles of extension through space and time in the Gulf of California

1. If you are only using this part of the RCL mini-lesson sequence, you might want to start with a brief introduction to research in the Gulf of California by using the RCL mini-lesson RCL Introductory Lecture (PowerPoint 2007 (.pptx) 2.5MB Sep11 15)
2. Detailed instructor notes are included at the bottom of each slide of the powerpoint lecture files. For the lab activity, detailed instructor notes are found within the Instructor Version file. The answers and follow-up discussion to the in-class activities are found within the associated powerpoint.
3. If you have already covered extension and normal faults, go directly to the second point. If your students are familiar with seismic profiles, go directly to the second half of the second power point for Gulf of California examples or to the Jigsaw Lab.

Three test questions that ask students to identify and interpret seismic lines from the Gulf of California:

Seismic Profiles Test Questions -- private instructor-only file

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In addition to these questions, several synthesis test questions probe students' cumulative learning of the physical characteristics of the Gulf of California and the processes that have shaped it.

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