Adopt a Blob

Catherine Cooper
Washington State University
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Blobs are everywhere in the deep Earth! Students will adopt a "blob" and develop the various associated observable anomalies for it (tomography, gravity, etc). There could also be a potential for students to adopt imaginary blobs that aren't physically real, but rather data artifacts. This assignment will help students in their own personal interpretation of deep Earth observables.

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Introductory Geophysics Class or other upper level undergrad geology course or graduate student course

Skills and concepts that students must have mastered

Introductory Geology, Mineralogy, Calculus, Physics

How the activity is situated in the course

The activity could be used as an ongoing project in the course with the student building on observables & interpretations of their blob as new information is introduced.


Content/concepts goals for this activity

Developing a multi-disciplinary & potentially quantitative outlook on deep Earth structures.

Higher order thinking skills goals for this activity

Hopefully by creating their own anomalies, students can gain an intuitive critical sense of interpreting geophysical images.

Other skills goals for this activity

Description of the activity/assignment

At the beginning of the course, each student is assigned a unique blob - or a piece of material of a particular shape with specific material properties (density, bulk modulus, composition, viscosity, volatile content, etc) that is residing within the mantle at a specific environment (depth, pressure, temperature). Then as the semester continues as a topic is covered the student must assess (either quantitatively or qualitatively) what observable would be associated with their blob (for example, gravity anomalies, geoid anomalies, surface expressions, seismic tomography, phase transition topography). The student then develops a portfolio of their blob and its observables to then present at the end of the course with an explanation/interpretation for the source of the blob culiminating at building a geo-story around their anomaly.

Some blobs could be amorphous anomalies whereas other could have physical significance (though best not to tell the students ahead of time so they can make their own discovery as to what the blob is or isn't) such as subducted slabs at the CMB (or 660 km), plumes, lithospheric drip, lithospheric root, or a boring typical piece of the mantle.

Determining whether students have met the goals

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