G446 / G546 Meteorites
Winter Term 2022
MWF 10:15 - 11:20 am, CH 69
A. Ruzicka (+ big iron meteorites + muffin)
Images of two very different meteorites, the Murchison (CM2) chondrite
at left, and the Henbury (IIIAB) iron at right [images: A. Ruzicka].
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
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.
(PDF file, posted Dec 30 2021; revised Jan 3 2022)
Here is a meteorite
image gallery for some (admittedly mostly not very good) photos I quickly obtained from the web. (Posted
Dec 30 2021)
the Bell et al. (1989) reading, feel free to skim/skip pp. 926-932 for
Sec. II. I'm mostly interested in discussing the 'big picture'
idea that is the centerpeice of this arguably forgotten article.
(Posted Dec 30. 2021)
- It looks like we've been assigned a new classroom to better allow the students that can't be physically present to join.
It is room FMH B129 (it's a special high-tech room dedicated to a
recent PSU president and his wife, I believe), and if possible I'd like
to give it a try for our second class meeting tomorrow (Wed Jan 5). I
don't know how to use the equipment in that room yet. But my hope is we
can get a Zoom link established so that remote users can join in.
Please check back with the course website tomorrow before class. Also
check your email, I may be contacting people that way. (posted Jan 4 2022)
- We are going to be meeting in FMH B129 today, which is our new classroom.
Also, for remote students, I have set up Zoom meetings for each of the
class periods in Canvas. Log in to Canvas, find the right meeting, and
connect. (Posted Jan 5, 2022)
- Hello Class, the rock and lab demo snuck up on me, it is tomorrow Jan. 26 (just in time to get a breather!). So for the Jan 26 class only, let's meet in our original classroom of CH69. We'll
have rock samples there for half the class to look at, and I will have
thin sections for the other half to look at in CH S10. Then we'll
swap. Sorry for the short notice! I've been missing a lot
of such things lately. Unless someone wants to take a video of
all this that we can post, there is no way I can let remote
participates join, sorry about that. (Posted Jan. 25 2022)
- Midterm instructions. The
Midterm on Friday Feb. 4 (open book, open note, short answer format)
will be done remotely to have a level playing field for all students;
we will not be meeting in our usual classroom. Instead, let's all login
to the regularly scheduled Zoom course meeting in Canvas (canvas.pdx.edu). The test will be
available to you as a Word document through a Canvas
module promptly at 10:15 AM on Friday. Be prepared to take photos of
or of your answer sheets. During the test, I will be available in
the Zoom meeting for you to ask any questions, either in the chat or
video link. You will have until 11:45 AM to submit your answers to me by email in whatever format works for you; I only require that I able to read
answers. Late submissions are subject to a penalty. (Posted Feb. 2
- For the Brearley (2006) reading, feel free to skim Sec. 3, 5, and 6. (Posted Feb. 11, 2022)
- Final Exam. The Final Exam is ready for you take. Check out Canvas for more details, and good luck! (Posted Mar. 14, 2022)
- Grades have been submitted.
Attendance wasn't curved; all other items were. Score
distributions are given below. Looking at Canvas, it will be easier to
send you emails with your scores and grades, so expect to receive an
email from me. If you want to pick up your work, please contact me and
arrange a time next term. Thanks for participating in the class. I know
it was challenging, but I hope you learned a lot. All of you
undergraduates are now in good shape for graduate level work if that is
your inclination. Have a great Spring Break and Spring term!
(Posted Mar. 21, 2022)
Glossary and concepts
Other reference materials
1. Due Jan 5 2022. (Posted Dec 30 2021, due date revised Dec 31 2021)
Score distributions and answer
- Midterm Exam Distribution. Here it is, finally. It might be helpful to have this before you take the Final Exam. (Posted Mar 4 2022)
Last updated: Mar 21 2022