HR: 0800h
AN: P41A-0917    [Abstracts]
TI: An Innovative Approach to Dating of Geomorphological Features on Mars With an In-situ Luminescence Dating Device
AU: * Kalchgruber, R
EM: rkalchg@okstate.edu
AF: Oklahoma State University, Department of Physics, 145 Physical Sciences II, Stillwater, OK 74078 United States
AU: McKeever, S W
P41A-0917 AF: Oklahoma State University, Department of Physics, 145 Physical Sciences II, Stillwater, OK 74078 United States
AU: Blair, M W
P41A-0917 AF: Oklahoma State University, Department of Physics, 145 Physical Sciences II, Stillwater, OK 74078 United States
AU: Deo, S
P41A-0917 AF: Oklahoma State University, Department of Physics, 145 Physical Sciences II, Stillwater, OK 74078 United States
AU: Reust, D K
P41A-0917 AF: Nomadics Inc., 1024 S. Innovation Way, Stillwater, OK 74074 United States
AU: Gupta, S
P41A-0917 AF: Nomadics Inc., 1024 S. Innovation Way, Stillwater, OK 74074 United States
AU: Strecker, B N
P41A-0917 AF: Nomadics Inc., 1024 S. Innovation Way, Stillwater, OK 74074 United States
AB: The surface of Mars has been subject to eolian, fluvial, and periglacial activity. Unfortunately, establishing a chronology for these events on Mars is difficult. Errors associated with crater counting are comparable to younger ages (~1~Ma) and consequently, techniques to quantify the ages of geomorphological processes on Mars have become an important area of research. Among the techniques proposed is optically stimulated luminescence (OSL) dating, which is well established for age-dating sediments on Earth. The time elapsed since deposition of a sediment layer is determined from the radiation-dose accumulated in minerals since the last sunlight exposure, and the dose rate due to naturally occurring radioactive nuclides and cosmic radiation.
The current paper addresses some of the challenges associated with developing an OSL device for in-situ dating of sediments on Mars. The instrument must be capable of luminescence dating with polymineralic samples for which there has been no chemical separation, requiring the identification of the predominant minerals likely to be found in the martian regolith, and the development of OSL procedures for these materials. The ambient temperatures on the martian surface are significantly lower than on Earth, requiring definition of the effect of the temperature variation during the irradiation period on OSL properties. Modelling of the martian solar spectrum indicates that the visible part of the spectrum is less intense than that on Earth, but the UV portion of the spectrum (~200--300~nm) is more intense, which may have profound consequences for OSL dating of martian sediments. Similarly, the radiation spectrum is dominated by cosmic and solar particles, requiring studies of radiation transport through the atmosphere and the efficiency at which these radiation types produce OSL compared with the calibration radiation source on-board the instrument. Results of experiments designed to address the above issues, using martian simulant materials, as well as a conceptual design of the OSL instrument will be described in this presentation. The project is funded by NASA (JPL Contract No. 1265427 under NASA RTOP No. 344-36-55-19 grant).
DE: 1160 Planetary and lunar geochronology
DE: 5400 PLANETARY SCIENCES: SOLID SURFACE PLANETS
DE: 5494 Instruments and techniques
SC: Planetary Sciences [P]
MN: Fall Meeting 2005