Department of Geology – Portland State University
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G410 / G510 Meteorites

Fall Term 2003

MWF 9:00 - 10:05 am, CH 69

A. Ruzicka (+ iron meteorites + muffin)


e-mail: ruzickaa@pdx.edu


Images of two very different meteorites, the Murchison (CM2) chondrite at left, and the Henbury (IIIAB) iron at right.

Murchison was derived from an asteroid that never melted, and which was rich in water and organic
materials.  These organic materials provide evidence for pre-biotic synthesis of organic molecules,
which appear to have formed originally in the interstellar medium. 
Bright spots in the meteorite are chondrules and refractory inclusions; fusion crust is the
brown coating at left.

In contrast, Henbury was derived from the core of a melted asteroid.
The core cooled very slowly (roughly 1 degree C per million years!) owing to its deep burial in the
parent body.  This slow cooling enabled the low-nickel metal alloy mineral kamacite to exsolve from the
high-nickel metal alloy mineral taenite, producing the intergrowth pattern (Widmanstatten texture) obvious
in the image. 


Course information

  • Reading list.  This is the list for the whole term.  See the "Glossary and concepts" and "Homework assignments" sections for more details on sections of the readings to skim.
  • 10-17-03 Change to schedule.  As mentioned in class, I am tweaking the schedule a bit to make some more time to focus on the main papers and to allow time for review.  The mid-term will occur on the same day as originally planned, but will  include topics covered only through Oct. 27.

Glossary and concepts

  • Clayton (1993), "Oxygen isotopes in meteorites"  This paper assumes a high level of background knowledge.  Don't worry if you don't understand all of it.  The link leads to a good primer on oxygen isotopes that you may find useful before looking at the Clayton paper.
  • Wadwha & Russell (2000) and Lugmair & Shukolyukov (2001).  There is considerable overlap between these two papers on the Mn-Cr system, and I think the latter article presents a clearer description of this, whereas the former is a better overview of other systems.  You might want to take this into account as you allocate time for the readings.  For the Wadwha & Russell paper, do a rapid read of section IIB.  For the Lugmair & Shukolyukov paper, skim much of the "Age of the Solar System" section, except pay closer attention to Fig. 5 and the last ("Some constraints...") portion.
  • Zinner (1998), "Stellar nucleosynthesis and the isotopic composition...".  In this relatively up-to-date account of pre-solar grains, you may have trouble seeing the forest for all of the trees.  Don't worry overly about the details the author provides.  Use the homework questions (HW #16) as a guide for focussing on the most important issues in the paper. 
  • Wasson (1985), "Iron meteorites: Evidence for and against core origins".  In addition to reading this paper, you should take another look at the last part (pp. 227-234) of the Dodd (1981) reading, our second one of the term.  Dodd discusses various chemical processes that affected iron meteorites, whereas Wasson focusses almost exclusively on fractional crystallization.



Other reference materials

  • Introduction to meteorites.  Click here to open a Powerpoint file (6.7 Mb).  The video clip may not work on your system.
  • Link to more recent classification tree.  This provides a more up-to-date listing of chondrite and achondrite groups than Sears & Dodd (1988) but doesn't show all the different iron meteorite groups.
  • Asteroids.  Click here to open a Powerpoint file (6.9 Mb).  This presentation covers many of the topics we have read about (orbits, spectra & albedo, space weathering) and also shows images of asteroids. 
  • Young stellar objects.  Click here to open a Powerpoint file (1.8 Mb).  This presentation is about newly-forming and newly-formed stars that have protoplanetary disks.  There's even an image that provides support for the nebular shock (clumpy accretion) model of chondrule formation.
  • Meteorite image gallery.  This page contains images retrieved from the web.  It will be periodically updated.  [Last update: 11-14-03.]

Homework assignments



Score distributions and answer keys


Last Updated:  12-14-03