Cordilleran Section - 113th Annual Meeting - 2017

Paper No. 20-8
Presentation Time: 4:25 PM


CAREY, Elizabeth, California Institute of Technology, Jet Propulsion Laboratory, 4800 Oak Grove Blvd, M/S 79-24, Pasadena, CA 91109, Elizabeth

Interpretation of Cassini RADAR and VIMS data has suggested some landforms on Titan may be due to effusive cryovolcanic processes that created cones, craters and flows [1]. High-resolution Voyager 2 images of Triton also show strong evidence of cryovolcanic features [2]. Fundamental to modeling of cryovolcanic features is the understanding of the rheological properties of cryogenic icy slurries in a thermodynamic and fluid mechanical context, i.e., how they deform and flow or stall under an applied stress. We performed a series of experiments on a 40 wt% methanol-water mixtures and 29 wt% ammonia-water mixtures, aimed at measuring the rheology of the slurries as a function of temperature and strain rate. These experiments revealed development of yield stress-like behaviors, shear-rate dependence, and thixotropic behavior, even at relatively low crystal fractions. Most importantly, we found that rheological properties of methanol-water slurries are strongly history dependent [3]. Visualization of icy slurries suggest that crystallization and the resulting 3-D arrangement of ice crystals dominate rheological properties. Viscosity measurements of methanol-water and ammonia-water slurries leads to constraining yield strength parameters to better inform dome formation models for locations in the solar system, such as Titan, where cyrovolcanism is a suspected formation mechanism of some geomorphological features. We will discuss our laboratory results and their implications for cryovolcanism on icy satellites.

[1] Lopes, R. M. C., et al., 2013. Cryovolcanism on Titan: New results from Cassini RADAR and VIMS. J. Geo. Res. 118, 416-435.

[2] Smith, B. A., et al., 1989. Voyager 2 at Neptune: Imaging science results. Science 246, 1422-1450.

[3] Zhong, F., et al., 2009. The rheology of cryovolcanic slurries: Motivation and phenomenology of methanol-water slurries with implications for Titan. Icarus 202, 607-619.