b'Petrologic Analysis of Samplesof the Miocene Altamaha Formation from Three Locations in the Central Georgia Coastal PlainMartice M. SeaSponsor: Dr. GroszosThe Altamaha Formation of Central Georgia is among the most durable rocks of the Southeastern Coastal Plain. This study seeks to compare Altamaha lithologies from three locations in Georgia: the Soperton, Georgia area, the Broxton Rocks Preserve near Broxton, Georgia, and the I-75 rest area near Ashburn, Georgia. Hand samples were examined using standard geological techniques including a conventional binocular telescope and hand lens. These samples have also been examined petrographically in previous studies. The Altamaha Formation is Miocene in age and is interpreted to be a terrestrial to shallow marine sandstone. This unit crops out across central Georgia as a well-indurated resistant lithology that caps many low-lying hills in the northern coastal plain. At present there are twelve samples, four from each location, that have been analyzed. In general, the three sample suites are quite similar with only minor differences. Most of the samples are well-indurated. All samples are clast supported with quartz being the dominant clast mineral. All samples show at least some iron oxide staining. Samples also show subangular to subrounded grains and are moderately to poorly sorted. Efforts to characterize these rocks are ongoing and additional results are pending.Particle Dynamics through the Earth:a study of Non-Zero tunnel diametersWalker HayesSponsor: Dr. MubinA standard problem in undergraduate mechanics derives the trajectory of a particle that has been dropped through a gravity tunnel passing through the center of the Earth as simple harmonic oscillation, assuming constant earth density and negligible tunnel diameter. We show that when the more accurate PREM density profile and non-negligible tunnel diameters are taken into consideration, significant deviations from harmonic oscillation are observed along with decreasing maximum particle speeds. Furthermore, we report that a particle travelling perpendicular to the axis of the gravity tunnel is unable to reach the center of the earth beyond a critical tunnel diameter of 71.36% of the earths diameter under a constant density, or 72.36% of the diameter under the PREM density model. When the rotation of the earth is incorporated, the particle released from the surface is observed to form planar trajectories that occasionally extend beyond the surface of the earth at large tunnel diameters, owing to tunnel-induced non-uniformity of the earths potential energy surface. In addition, we numerically calculate the brachistochrone connecting two points on the surface for various tunnel diameters using the PREM density profile. The results presented demonstrate the effect on the overall potential energy surface and particle dynamics when the tunnel diameter is not negligible.47'