[MSA-talk] Plate tectonic Ig/Met Pet syllabus

Johnson, Elizabeth Baedke - johns2ea johns2ea at jmu.edu
Thu Dec 28 12:36:29 EST 2017


I teach Igneous and Metamorphic Petrology to sophomores and juniors.  The course is organized in a spiral learning format.  This means that we revisit concepts learned in the first part of the course during the second part of the course in the context of tectonic case studies.

In the first half of the semester, we work on identification of igneous and metamorphic minerals, rocks, and textures, and some whole-rock major element geochemistry.  We use some smaller case studies in the first half of the semester to apply knowledge (Peninsular Ranges Batholith, Cascades), but the main focus in the first part of the semester is skill-building.

During the second half of the semester, students must recall textural terms, identification methods, geochemical concepts, plus they must add to these skills with field observations, additional thermodynamic/geochemical techniques, and must interpret the data within plate tectonic and/or mineral resource contexts.  I use three case studies: the Bushveld LMI, our local western VA Eocene/Jurassic volcanic rocks, and the metamorphic and igneous history of southwestern VA.  The last two involve magmatic processes and tectonics, and are also local/regional so the students can see the rocks, or similar rocks, in the field.

I do not hide the pedagogy from the students - I explain at every step why we are "doing" the different types of rocks twice in the same semester.  I think the format has two distinct advantages: 1. introducing material and then re-using it a month or two later gives some time for students to process the knowledge and then apply it, hopefully for greater retention; and 2. it is a method that allows at least the last half of the course to be formatted in a case-study/tectonics format.  Most of our students would be overwhelmed if I immediately jumped into the higher-order conceptual skills for detailed tectonic case studies at the beginning of the semester.  This, of course, may be very different for other curricula or graduate-level courses.

The biggest disadvantage I have encountered in this course format is for the few students (perhaps 1 out of every 40-50 students) who struggle to keep up with vocabulary and chemistry skills in the first half of the semester.  If they cannot master the first part with a grade of C or better, then they have even more difficulty applying these skills to the case studies.

Hope that helps!  I am happy to share learning objectives / exercises with anyone who is interested.
Liz Johnson
Associate Professor
Department of Geology and Environmental Science
James Madison University
From: msa-talk-bounces at minlists.org <msa-talk-bounces at minlists.org> on behalf of David Dolejs <david.dolejs at minpet.uni-freiburg.de>
Sent: Thursday, December 28, 2017 5:08:57 AM
To: msa-talk at minlists.org; Matthew Kohn
Subject: Re: [MSA-talk] Plate tectonic Ig/Met Pet syllabus

Dear Matt and all,

this is an interesting idea -- I have been dealing with similar isuue
for some time, primarily driven by question how to design petrology
courses at three subsequent levels from junior bachelor to senior master
level.  I like to place emphasis on geodynamic context at the advanced
bachelor level and on physico-chemical aspects (structure and properties
of silicate melts, phase diagrams, metamorphic thermodynamics,
deformation mechanisms) in the master.  I realize that this may also
offer additional advantage if your bachelor curriculum does not have a
senior bachelor class on plate tectonics (or geodynamics).

I am not sure if you want to couple igneous and metamorphic processes
together or just place igneous or metamorphic aspects into geodynamic
structure of your course.

For the igneous part, I start with mid-ocean ridges (vertical structure
of the Earth's mantle, adiabatic melting), then subduction zones
(fluid-present melting or "silicothermal" plumes, differences imposed by
water and oxidation state leading to contrasts between tholeiitic and
calc-alkaline series), mechanisms of magma differentiation (MASH) in the
arcs, continental collision (dehydration melting, types of partial
melts, differentiation towards granites, granite types),
post-collisional extension, anorogenic settings (anorthosites, aluminous
A-types), plumes and continental breakup (systematics of basaltic melts
with pressure and degree of partial melting, origin of carbonatites,
continuum of basaltic-kimberlitic-carbonatitic melts, differentiation
and diversity of alkaline rocks).  It may not be bad to start with
plumes (+ LIP), breakup (layered intrusions), rift, ridges etc. until
post/anorogenic settings.

For the metamorphic processes, a comparable scheme is more difficult to
build.  Perhaps one way is to introduce metamorphic gradients in
geodynamic and temporal context (see reviews by Mike Brown), then follow
similar framework as above: low-pressure metamorphism near mid-ocean
ridges (sea floor), high- und ultrahigh-pressure metamorphism in the
subduction zones (+ discussion of mechanics, de/relamination, exhumation
etc.), metamorphic pairs in arcs (adding low/medium-P metamorphism of
the arc crust), collisional metamorphism (Barrovian type), extension of
the continental crust, exhumation of metamorphic domes, migmatite
complexes (possibly melting in the crust), concluded with metamorphic
styles in the Archean.  It will, however, be difficult to find resources
for this type of class (perhaps: Johnson & Harley; Nicollet -
Metamorphisme et Geodynamique).

If you truly want to mingle metamorphic and magmatic processes, then I
would look at geodynamic resources (Frisch et al.; Condie) and condense
it from those.

I would be happy to hear anyone else's opinion as well.

Best wishes, also for the new year, to all,

David Dolejs  (Professor of Mineralogy & Petrology)
Institute of Earth and Environmental Sciences, University of Freiburg
Albertstr. 23b, 79104 Freiburg i.Br., Germany
Tel direct: +49 (0)761 203 6395 / secretary: +49 (0)761 203 6396
Fax: +49 (0)761 203 6407
Web: https://urldefense.proofpoint.com/v2/url?u=http-3A__www.minpetro.uni-2Dfreiburg.de_team_dolejs&d=DwICAg&c=eLbWYnpnzycBCgmb7vCI4uqNEB9RSjOdn_5nBEmmeq0&r=8ivoI-c3gh7dtnuZEmjyQw&m=0XgTGSwprkpnc7KFT9SnhIr2Xzkzx52YLBahIwqeZMY&s=m-1gmN5qROb7TgUeKyGlsAsp8oRTEV4E-hLDXeWLI1E&e=
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