Overview: Rupturing Continental Lithosphere Mini-Lesson Sequence

Becky Dorsey, Scott Bennett, Sue Cashman, Melissa Lamb, Jack Loveless, Andrew Goodliffe

Summary

The Rupturing Continental Lithosphere (RCL) mini-lesson sequence is designed to explore the geologic processes that control continental rifting and its progression to lithospheric rupture. This sequence showcases a decade of recent findings from the focused research efforts by the NSF-MARGINS program in the Gulf of California-Salton Trough rift, a classic example of an obliquely rifted margin. These modules illustrate how the findings from RCL research in the Gulf of California have helped to progress and evolve the understanding of how rift obliquity, sedimentation, and magmatism can control the style of rifting and lithospheric rupture.

The RCL mini-lesson sequence comprises:

  • Introduction - This introductory page highlights the NSF-MARGINS Rupturing Continental Lithosphere research initiative and the processes and factors that control rifting and lithospheric rupture. This page also introduces the individual mini-lessons that explore these characteristics and controlling factors.


Observational activities:

  • Bathymetry of Rifted Margins - A module in which students investigate the morphology of rifted margins by creating topographic profiles and describe north-to-south variations in basin morphology in the Gulf of California. This lesson can act as an introduction to more detailed examinations of the roles of sedimentation and obliquity in rifted margins.


  • Exploring Styles of Extension in the Gulf of California - A module that serves as an introduction to continental rifting and extensional features. Students are introduced to different styles of deformation during continental rupture. Examples of geophysical data (e.g. seismic reflection) are used to explore the variety of extensional features in the Gulf of California through space and time.


Process-based activities:


  • Google Earth view of Gulf of California with plate motion contours overlain
    Role of Plate Motion Obliquity in Rifting - A module that uses Euler poles to describe the relative motion between the Baja Microplate and North American Plate, highlighting how the obliquity of rifting changes along strike in the Gulf of California.


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Learning Goals

The mini-lessons can be used together or individually. The information in the introductory lecture provides an overview of the RCL project and its main science results, while the wrap-up presentations for each mini-lesson summarize those lessons while placing them in the context of the other lessons.

If students complete all or several modules within this RCL mini-lesson sequence, they should be able to:

  • relate physical characteristics of the Gulf of California to processes that cause rifting and lithospheric rupture
  • explain what new insights regarding rifting have come out of recent Gulf of California research
     



The mini-lessons develop technical skills in:

  • GeoMapApp: create contour maps and profiles, extract data
     
  • Google Earth: import kmz maps, overlays, create profile lines
     
  • Excel: import data, sort and analyze data, make & analyze plots
     
  • Matlab: import data, calculate using trigonometric functions, make & analyze plots
  • Interpreting seismic data

Context for Use

Upper-division course in Structural Geology, Plate Tectonics, or Regional Tectonics

This RCL mini-lesson sequence contains 5 parts — an introductory presentation and 4 teaching modules — allowing flexibility based on course duration, time constraints, and scope. Instructors can use all RCL mini-lesson materials provided (~15–20 hours), or select individual modules (~2–3 hours each) to use in the classroom (see schematic flow chart). We recommend that users of individual modules start with the Introductory Lecture and exercise about rift bathymetry (this page) and follow with any selected module.

Description and Teaching Materials

Introductory Lecture (PowerPoint 2007 (.pptx) 2.5MB Sep11 15) (15 minutes): A brief introduction to the NSF-MARGINS Rupturing Continental Lithosphere research initiative and the processes and factors that control rifting and lithospheric rupture.

RCL Mini-Lesson Wrap Up Lecture (PowerPoint 2007 (.pptx) 8.4MB Nov3 15) (15-40 minutes): A lecture that provides a summary of all RCL research findings as explored in the various mini-lessons. The slides in this presentation can be used to wrap-up the mini-lessons that were used, as well as summarize the scientific results presented in mini-lessons that were not.


Assessment

Individual RCL mini-lessons provide exercises and/or test questions with answer keys.

ask students to synthesize their knowledge by describing the physical characteristics of the Gulf of California and the processes responsible for its formation. Students who complete all mini-lessons should be able to provide a comprehensive description of the Gulf's bathymetry and sub-surface structure, along with descriptions of how sedimentation and obliquity of rifting influence those characteristics. In courses incorporating only a subset of the mini-lessons, the closure lecture can be used to supplement student knowledge by illustrating major findings from all mini-lessons.

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