2009 Portland GSA Annual Meeting (18-21 October 2009)

Paper No. 8
Presentation Time: 9:00 AM-6:00 PM


MILLER, Jeremy J., Department of Geosciences, The University of Texas at Dallas, 2400 Waterview Pkwy. #411, Richardson, TX 75080, jmiller26_2@msn.com

Many examples of sediment deposition in aqueous Martian environments have been revealed in the past few decades of exploration. Fluvial gully, deltaic, and lacustrine depositions exist among the paleoenvironments that can be determined from remote sensing images. Sediment deposition in water is greatly affected by its settling velocity. This, in turn, is directly affected by each individual particle’s downward acceleration due to gravity, according to a derivation of Stokes’ Law for finding settling velocities for round particles with very small Reynolds numbers.

The NASA Reduced Gravity Student Flight Opportunities Program is accepting submissions for participation to conduct experiments in the cargo bay test area of its modified KC-1 35A turbojet transport which flies a series of parabolic arcs to produce periods of micro-, hypo-, and hyper-gravity that can last up to about half a minute. The experiment proposed here will include measuring differences in settling rates between particles of differing sizes ranging from fine sand to gravel. NASA’s KC-1 35A turbojet can simulate Mars-gravity (3.7 m/s2) for approximately 30 seconds. Therefore, because of the lengthy settling rates of particle sizes smaller than fine sand, these smaller sizes will not be experimented with. We will experiment with liquid viscosities of pure distilled water, hypersaline water, and many other viscosities that can be assumed to have been on Mars’ surface in the geologic past.

The primary purpose of this experiment will be to determine the reliability of Earth analogs for aqueous paleoenvironments on Mars and whether modifications should be made to our interpretations of these sedimentary structures based on the differences in each planet’s gravity. If sedimentation rates are affected by gravity disproportionally across the spectrum of grain sizes, then Martian aqueous geomorphology could indeed be different from Earthling analogs. A secondary purpose of this experiment is to determine the validity of the Stokes’ Law derivation for finding terminal velocity of particle settling among different Reynolds number values and different gravitational values.