1. EART193 Planetary Capstone
Francis Nimmo

2. Jeff Moore Jeff will visit from NASA Ames this Thursday
I asked him to talk about cryovolcanism on Titan and Pluto/Charon
I’ve posted the two relevant papers online

3. Cautionary Tales Ganymede (Voyager) Ganymede (Galileo)
Enceladus (Voyager vs. Cassini)
Moore & Pappalardo 2011
Scale bars are 50 km

4. Cayley Formation (Moon)
Smooth mantling deposits, interepreted as ash falls / pyroclastic flows
Apollo 16 ground truth revealed it was all impact ejecta!

5. The right approach

6. Tortola Facula

7. Ganesa Macula

8. Hotei Arcus

9. Titan chemistry Methane lifetime ~10 Myr – implies recharge
Photodissociation
Hydrogen escapes
Ethane condenses at 101 K
Reactions produce more complex organics
Clouds plus organic haze
Methane recharged
Organic drizzle
Surface 94K
Ethane etc. lakes
After Coustenis and
Taylor, Titan, 1999
Underground aquifer?
Methane lifetime ~10 Myr – implies recharge
Recharge requires outgassing of CH4 from interior (e.g. by “cryovolcanic” activity or clathrate decomposition)

10. Fig. 5 Quasicircular mounds south of SP, both with depressions at their summits, which may have a cryovolcanic contribution.
Quasicircular mounds south of SP, both with depressions at their summits, which may have a cryovolcanic contribution. Dashed lines mark their approximate boundaries. Image is 320 m/pixel, reprojected MVIC coverage of the P_MVIC_LORRI_CA observation. (A) Wright Mons at 22°S, 173°E. (B) Piccard Mons at 35°S, 176°E, seen in twilight. (C) Colorized DEM overlain on the MVIC coverage of the mounds. “a” marks Wright Mons, “b” marks Piccard Mons.
Jeffrey M. Moore et al. Science 2016;351:
Published by AAAS

11. Fig. 6 Enlargement of a portion of Fig
Fig. 6 Enlargement of a portion of Fig. 1B showing details of Vulcan Planum on Charon.
Enlargement of a portion of Fig. 1B showing details of Vulcan Planum on Charon. (A) Image is 1460 m/pixel MVIC coverage from the C_COLOR_2 observation, centered at 5.5°N, 3°E, with north up. (a) Depressions with lobate margins; (b) mountains surrounded by moat-like depressions; (c) deep, rille-like troughs; and (d) shallow, finely spaced furrows. White outline indicates high-resolution image in (B). (B) High-resolution view of resurfacing on Vulcan Planum. Image is 160 m/pixel, reprojected LORRI coverage from the C_MVIC_LORRI_CA observation centered at 0°N, 0.5°E, with DEM color overlain. Seen in this LORRI view are rille-like troughs (e) and more finely spaced, shallow furrows (f), smoother regions of lower crater density (g), a pancake-shaped deposit (h), and unusual textured terrain (i). Clarke Mons (j) lies in a depression, which is itself bordered on two sides by distinctive lobate scarps. (k) A field of small hills.
Jeffrey M. Moore et al. Science 2016;351:
Published by AAAS

12. Pancake domes on Venus
(McKenzie et al. 1992)
What viscosity was the magma that formed these objects?
h=1.5 km, r=15 km

13. Viscosity Implied viscosity ~1015 Pa s
Charon (Moore et al. 2016)
Implied viscosity ~1015 Pa s
This is very high – like glacial ice on Earth or Mars i.e. solid not liquid.
Ariel (Schenk 1991)

14. Timeline Thurs 8th June - guest lecture by Jeff Moore (NASA Ames)
Final essays due **5pm on Mon 12th June**.
We'll do the oral presentations in the exam slot, Weds 14th June, 12-3pm.
Plan on giving a 15 min talk.