[MSA-talk] Plate tectonic Ig/Met Pet syllabus
spera at ucsb.edu
Wed Dec 27 18:06:51 EST 2017
I did this some years back maybe 20 yrs ago…. what i did was make the petrology completely oriented towards a petrotectonic approach. in particular, i started by following a representative volume of mantle from >TZ depths (so i got to do the mineralogy of the whole mantle) and then dynamically followed that parcel through a (circa 300 million year) circuit/cycle. So started with peridotite+- eclogitic mantle, bring it up , discuss its quasiisentropic partial melting, getting into dynamics of melt segregation ,collection, and ascent via cracks, erupt it at MOR, then get into the hydrothermal metamorphism/metasomatism v business near ridge, then move it away from MOR and discuss the meta. facies in mafic composition, integrated with geothermal and sea floor weathering…. then across the basin (somewhat boring altho zeolites can be interesting in their own right) and to the subduction zone where a host of integrated topics are naturally considered… fluids? off the slab, wedge partial melting ,ascent and metamorphism in rocks around the magma that gets stuck at depth ( orientation of mean stress tensor…dikes or sills etc) , sigma three horizontal leading to conduits feeding arc volcanism… it took me about 12 weeks to do this and i integrated the labs. this required some re thinking of traditional ig/met pet labs but it did seem to make better sense to the students…..as fas as texts, i never found one, and just rolled my own, so-to-speak. i did start working on one in fact but soon was swamped with other things and gave up…….when i retire , THEN i will…. haha… the grad curriculum changed after a few years and at UCSB we do it differently now so i only did this version for about three cycles right around the Y2K epoch (for those old enuf to recall that)
i really enjoyed this approach as it does put petrology into a dynamic context and the place to put all the traditional topics is self evident… i.e. when one discusses the quasi-isentropic melting of a parcel of mantle stuff , this is the logical place to insert phase equilibria, phase diagrams and discuss how melt gets mobilized… Similarly when discussing the thermal field in a downing slab, many of the metamorphic pigeon holes in PT space can be discussed and all that fun fun fun stuff. Of course, the hardest part for me was deciding what to include and what to leave out…. unfortunately the old syllabi and class notes were in ancient versions of WORD and i never updated regularly and are now Extinct!
anyway, sorry for this long email but perhaps in some tiny way my memory of how i did it , which can i am sure be improved upon, might be of a minor aid to you.
Professor Frank J. Spera
Dept of Earth Science
University of California
Santa Barbara, CA 93106
There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy.
- Hamlet (1.5.167-8), Hamlet to Horatio
> On Dec 27, 2017, at 6:57 AM, Matt Kohn <mattkohn at BOISESTATE.EDU> wrote:
> I’m teaching igneous and metamorphic petrology this spring, and I’d like to experiment with approaching it with a plate tectonic/Earth processes structure.
> For example, for one block of the class, I might couple subduction zone metamorphism with arc volcanism. Or, continental collision - type regional metamorphism with partial melting and production of S-type granites.
> I haven’t been able to find a syllabus that covers Ig/Met pet in this way.
> Yes, I’ve looked on the SERC website.
> Does anyone have a lead on just such a course design? I’d really rather not make any mistakes that others have discovered.
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