High Strain Rate Planetary Mechanics

High Strain Rate Planetary Mechanics

Mars Seminar

Mars Seminar

High Strain Rate Planetary Mechanics

High Strain Rate Planetary Mechanics

Thanks for the Seminar!

Hey that was great!!!

This blog will self-destrruct in, oh, about a year.

Readings for Wed March 2: Ground Ice

MellonEtAl2004.pdf
BoyntonEtAl2002.pdf
MangoleEtAl2004.pdf
FeldmanEtAl2004.pdf
TitusEtAl2003.pdf
MangoldAllemand2001.pdf
MellonPhillips2001.pdf

Find them at the usual place...

Erik

P.S. I am away in DC this week -- all is back to normal next week!

Slawek's Readings On Line

The readings for next Wednesday are now online:

http://ic.ucsc.edu/~easphaug/mars/slawek_readings/

There will be no Monday afternoon meeting. Email questions about the readings to slawek, and I'll see you all in a week,

Erik

How to pick your LPSC abstract (due FRIDAY)

Please Do the Following:

1. Go to http://www.lpi.usra.edu/meetings/lpsc2005/lpsc2005.download.html to download the abstracts by session -- the best way to survey all of what's out there by theme. Or, find it any way you want. Write down the lead author and abstract number.

2. Locate your abstract number (find it by lead author) at http://www.lpi.usra.edu/meetings/lpsc2005/a-f.html

Hint: a specific abstract URL looks like this: http://www.lpi.usra.edu/meetings/lpsc2005/pdf/1961.pdf
(hey that's Delia's!)

3. Click on "comments" below, and add a comment to this post, where you give the link for the SPECIFIC ABSTRACT you want us to read, which you'll be responsible for in discussion.

Clear? Alles gut?

Poor Pluto (off topic)

http://www.thepaincomics.com/weekly050119a.htm

THEMIS image from class

Example of problematic crater dating

http://themis-data.asu.edu/img/browse/I08988002

Readings for Wed Feb 9: Polar Layered Deposits

Nature Articles Galore: on the web site please find

Howard02.pdf
Thomas00.pdf
Laskar02.pdf
Head03.pdf
Richardson02.pdf

These are short articles -- please feel free to load up your jump drive with other stuff, or post it online here!

Cheers
Erik

post that funky image

can somebody please post that image of the exhumed equatorial glacier in Valles Marineris (not to prejudge what it is), MOC and THEMIS or others,
Thanks!
Erik

Readings for Wed Feb 2: Valley Networks

1. http://ic.ucsc.edu/~easphaug/mars/Mangold04.pdf
Don't forget to read the Supporting Online Materials for the above,
www.sciencemag.org/cgi/content/full/305/5680/78/DC1
Figs. S1 to S3
Table S1
References

2. http://ic.ucsc.edu/~easphaug/mars/Craddock&Howard02.pdf
(a chunker... ties in closely to Mangold04.pdf; skim it first, then
read it more carefully as time allows)

3. http://ic.ucsc.edu/~easphaug/mars/Goldspiel&Squyres00.pdf
A clearly articulated alternative view.


There is a LOT of reading for this class. This is your ONLY homework, and is what you can expect to do pretty regularly
as a scientist. Get into the articles, e.g. if you don't understand a key point, dig into some supporting materials, and be ready to get to the bottom of things during discussion. Also, undergrads, please remember to come by tea time, 3:00 in my office on Mondays.

A Drizzly Cryo-Nevada

Or something like that... see below.

Apply Earth geomorphic analogues at your peril, however. CH4 is not a polar molecule like H2O, and thus liquid methand is not a van der Waals fluid, not (perhaps) as "wet" as water. And the rock being eroded is predominately 90K water ice mixed with organics, presumably.

Whatever it is, you got to love saying "cryoplaya"!

From: Bruce Moomaw
Date: Fri Jan 21, 2005 3:57 am
Subject: Titan as a rainy world

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Those of you who watched that rather intimate little Huygens press conference (virtually all the talking was done by Tomasko, Zarnecki and Tobias Owen, in a rather small room) already know all this. But for those of you who didn’t: the first big discovery of Hugyens seems to be that methane rain, contrary to what a lot of theorists thought, DOES hit the surface of Titan directly—and pretty frequently. The landing site is (as I suspected) rather like a terrestrial desert with arroyos and a big playa, which seem to be currently dry—but they were rained on quite a short time ago (the general impression was left that it was less than a year), and the playa is still muddy. And that smooth, pebble-free region running through the middle of the post-landing photo is indeed thought to be a small, recently wet steream channel (although it’s not wet now; they haven’t seen any signs yet of liquid pools or puddles actually on the playa’s surface at the moment). I imagine the rain comes from those small wandering clumps of methane clouds seen by Cassini; they may be small, but they seem to be very moist, and they may be lower-altitude than previously thought. They may, in fact, be pretty damn dramatic thunderstorms.

Some of the arroyos were definitely carved by surface rainfall; others, with stubbier branches, seem to be sapping channels coming from springs. Also, John Rehling was right in noting that some runoff channels run across the “peninsulas” of stone-studded terrain sticking into the playa. The suggestion was made that these are places where the liquid poured from one part of the playa into a somewhat lower part—but I’d like to know whether the possibility can be completely ruled out that both they and the springs might be tidally driven phenomena instead, if the tides on Titan are as powerful as has been suggested. Anyway, the rain washes the dark smog off higher terrain on Titan and it accumulates as a dry crust in the arroyos and playas after the liquid evaporates, as we thought. I imagine that—given the very slow rate at which the smog is produced—virtually all of it actually gets caught up in the raindrops and carried down onto the surface by them. I suspect that those light-colored streaks seen by Cassini to the leeward side of high features on Titan are not, as I thought, wakes where dry smog dust has not been blown by winds—but rain shadows instead.

The second big revelation, although less was made of this, is that cryovolcanism is definitely occurring on Titan, and pretty vigorously. One photo taken from serveral km up showed, plain as day, a very light-colored narrow “tongue” of very clean water ice stretching across the landscape, with arroyos starting immediately at its edges and flowing away from them—as though it was a fairly high, smooth dome of water ice extruded from underground, with the surface so smooth and hard that the rain falling on it doesn’t erode it, but instead runs off its slopes onto the older ground-up water ice regolith immediately to each side of it and starts carving gullies only then. But that means that the icy surface of this ridge must be relatively recent, and hasn’t been ground up yet into loose ice regolith by meteoroid impacts and whatever other processes slowly grind up the surface ice of Titan. Also, they got some good stereo pairs from the photos—and the ridge running close to and parallel to the shore in that famous photo of the runoff channels near the shoreline, with rainfall channels running off it on both sides, must be about 100 meters high but only several hundred meters wide. In short, Titan is NOT the flat world I had suspected it was—except in the basins where the liquid runoff and muddy sediment have accumulated. (No speculation from them as to what’s driving the cryovolcanism. Tidal heating?)

Zarnecki confirmed that lab tests do indeed show that the penetrometer profile can be simulated by the instrument’s staff ramming through a thin dry surface crust and into softer muddy material below, and that the whole probe seems to have sunk 10-15 cm into the mud. And the heated GCMS inlet, starting 3 minutes after landing, evaporated enough liquid methane out of the mud to raise the gaseous CH4 level going to the GCMS by 30%. (The only other mention made at this point of any other substances detected by the GCMS is that some heavier organics also seem to have been vaporized out of the mud by the heated inlet.) It starts to look as though the methane clouds build up just below the methane cold trap that separates Titan’s troposphere and stratosphere, and as I say may grow into pretty dramatic thunderstorms—although Fulchignoni, who was at the press conference but did very little talking, didn’t say anything about any possible detection of radio bursts from distant lightning bolts.

Other things I would have liked to hear more about but which weren’t mentioned, besides tides and lightning: the argon level; the altitude (once again) of the lowest pre-landing photos (although the photos they did get, having been greatly improved by further processing, seem more than adequate to give us a good idea of what’s going on on Titan); those possible clear liquid droplets on the DISR’s windows; and the significance, if any of that double spike in the echo sounder’s data (a dried surface crust with a moderately deep mud layer below it, as hinted by the penetrometer?) But Titan has turned out to be a nice dramatic place after all, and much wetter than I really expected it to be—now unquestionably the first world besides Earth to have a good deal of liquid on its surface (and not just ethane, but liquid methane) -- as well as being a lot more internally active than anyone seems to have suspected. In short, Huygens—even with only one communications channel working—has delivered the goods, in no uncertain terms

Visual Treats

Assignment for Wednesday Jan 26:

In addition to the reading, everybody in class is to bring a Visual Treat, with the goal of (a) relating this visual treat to the readings and (b) leading some discussion pertaining to it for about 5-10 minutes.

P.S. Undergrads coming to office tea time, Monday 3:00-3:30 in A108 -- please bring your readings with you, and have at least skimmed all of them over the weekend to enable some worthwhile pre-seminar discussion. That's going to be the general drill for Mondays.

Readings for Wed Jan 26

1:
http://ic.ucsc.edu/~easphaug/mars/Clifford&Parker01.pdf
This is a pretty thorough overview of one of the major paradigms for the Martian hydrosphere, cryosphere and the origin of channels

2:
http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1997JGR...102.4151K&db_key=AST&high=40719f51da02334
a.k.a. Komatsu and Baker, JGR 1997 (I will put online later today -- feel free to do so first and post a link!)
This paper describes a model for Ares Vallis.

3:
http://ic.ucsc.edu/~easphaug/mars/Wilson04.pdf
This paper goes into detail regarding how flood geomorphology can be scaled to Mars.

Titan Images

one stop shopping at http://anthony.liekens.net/index.php/Main/Huygens

Permission Codes

Email me TODAY if you need a permission code for the class, and
I will send you one ASAP. I got them now.

Erik

Joe Kirschvink's Talk Friday

Not to be missed!

Our IGPP Seminar series for Winter Quarter 2005 continues this Friday, January 14, 2005.  The seminar is sponsored by CODEP.

Speaker/Affiliation:

Joe Kirschvink
Caltech

Seminar Title:


"A Paleoproterozoic Planetary Suicide Attempt: Did The Evolution of Oxygenic Photosynthesis trigger the first Snowball Earth?"

Abstract:

The rise of oxygenic photosynthesis and the oxygenation of the atmosphere are two of the most important events in Earth history. A preponderance of evidence now supports the hypothesis that planetary oxygenation occurred between 2500 Ma and 2200 Ma. While biomarker evidence has been used to claim that oxygenic photosynthesis evolved several hundred million years before the oxygenation event, doubts remain about both possible sample contamination and the reliability with which biomarkers can be tied to oxygen-demanding pathways. Moreover, the co-incidence of planetary oxygenation with the Paleoproterozoic Snowball Earth suggests an alternative history, in which the evolution of oxygenic photosynthesis triggered the geologically rapid destruction of a methane greenhouse and a Snowball Earth event. We propose a new correlation between the Huronian Supergroup, Canada, and the upper Transvaal Supergroup, South Africa, in which the three Huronian glaciations predate the oxygenation event while the Paleoproterozoic Snowball Earth was triggered by it. A simple computational model of C, Fe, and P fluxes during the oxygenation event suggests that, under a range of plausible fluxes, cyanobacteria could have destroyed a methane greenhouse and triggered the Paleoproterozoic Snowball Earth on timescales as short as 1 myr. The geologic record currently permits multiple testable hypotheses about planetary oxygenation and all deserve critical consideration.

Host:
Don Korycansky

When:
Friday, January 14, 2005 at 3:30 P.M.

Where:
Natural Sciences Annex, Room 101

Refreshments will be provided in the E&MS Dreiss Lobby at 3 P.M.  Please Join Us.

New Room = D226

We changed the time, so we had to hunt for a new room!

We've secured D226 for our Wednesday meetings from now on, aloha!

I'm going to bring the projector and the laptop and an internet cable (assuming I can track down our projector!)

Erik

Upcoming Readings

The following is a slight edit to Friday's post.
Also -- you must reload the page to see new stuff.

For Monday Jan 10 (special class, 12:30-3:30):
http://ic.ucsc.edu/~easphaug/mars/Jakosky&Phillips01.pdf
http://ic.ucsc.edu/~easphaug/mars/Squyres04.pdf

For Wed Jan 12:
http://ic.ucsc.edu/~easphaug/mars/Catling04.pdf
http://ic.ucsc.edu/~easphaug/mars/Levrard04.pdf

For Wed Jan 19 (detailed atmosphere & climate evolution reviews)
http://ic.ucsc.edu/~easphaug/mars/Pepin94.pdf
http://ic.ucsc.edu/~easphaug/mars/Haberle98.pdf

Wednesdays it is...

Thanks, those of you who made leaps to make it into the Wed 2-5 time slot! I know it's not easy. This means we don't have to re-adjust for the two Monday holidays.

We meet This Monday Only, Jan 10, at 12:30 - 3:00 to discuss
Squyres04.pdf
Jakosky&Phillips01.pdf

and then Wednesdays at 2-4:30 from Jan 12 on.

Undergraduates will meet for an additional 30 minutes just before the department Tea Hour. for review. Come by A108 at 3:15 Mondays, and bring the coming Wednesday's reading with you in hardcopy.

Files All Organized Now

The readings (including some new candidates) are now organized in the directory, where I have culled the ones we did not like.

Those of you who were tracking down other readings, can email them to me at any time. Just in time for classes, Instructional Computing messed up their entire file transfer protocol (and changed our userids just to make sure only the Few and the Proud can get any work done), but we'll survive.

Erik

New Paper Suggestion

I suggest that we also add this paper

Acid-sulfate weathering of sythetic Martian basalt: The acid fog model revisited.
by Tosca et al
JGR-planets May 2004 (E05003)

I haven't done more than skim it yet, but it was mentioned several times at AGU, so I think it is something we should be current on. In addition, it deals with soil formation soley interacting with atmosphere. Could be good for trying to understand some of this remote sensing spectral data.

Documents Online

The documents online at

ic.ucsc.edu/~easphaug/mars

now include those recommended more recently, in the subdirectory called "More"

David Grinspoon on Mars Exploration Rovers

Link to a fun article by David Grinspoon, on the MER rovers:

http://www.latimes.com/news/opinion/commentary/la-oe-grinspoon3jan03,1,7418621.story?coll=la-news-comment-opinions

Class Schedule

Greetings Earthlings!
Happy New Year.

The schedule for our seminar class is:

Wed 3-5
Earth & Marine Sciences D258

Erik

Introducing the Winter 2005 Planetary Science Graduate Seminar

Earth Sciences 290E
Mars Atmospheric and Geomorphic Evolution

Co-taught by Erik Asphaug and Slawek Tulaczyk

This is a class for graduate students, although undergraduates are welcome to attend by prior permission of either instructor. It will focus on the primary relevant research literature and meet once a week, 3 hours including a break (TBD).

The theme is Mars and how it got that way, with a special concern for atmospheric and climate evolution, sources and sinks and reservoirs for water, evidence for past "wet and wild" episodes and their instigations, and the half dozen or so major theories-du-jour, all of which hover around the central question (not specifically asked by this seminar): does Mars have bugs?

Candidate reading list is found here . Please email me with any recommendations!

Seminar participants will use this blog to facilitate class discussion outside of the regularly scheduled seminar.