HR: 0800h
AN: V21B-0604    [Abstracts]
TI: Quartz Hydration Dating in a Geological Perspective
AU: * Ericson, J
EM: jeericso@uci.edu
AF: Jonathon Ericson, Department of Environmental Health, Science, and Policy, UCI, Irvine, CA 92697-7070 United States
AB: Quartz hydration dating (QHD) is a new direct geochronological technique. The technique measures the lapse time since the fracture of coarse grained (>3mm) quartz crystals. It relies on the phenomenon of water diffusion into quartz leading to the formation of a hydration layer at that can be measured by a nuclear reaction of hydrogen by particle acceleration or SIMS. Diffusivity coeffients for temperature, crystallographic orientation due to anisotrophy of quartz and the initial H content provide a general equation for calculation of age. The activation energy is 57 kJ/mole in the temperature range from ambient to 200C. The time range of QHD is 100-100,000 years. The error is 20-35% depending on the defects in the quartz structure and exposure temperature. The dating of fractured quartz crystals has numerous geological applications, applied to earthquake recurrence intervals, chronology of volcanic eruptions, meteorite impacts, mass wasting, weathering and fracture during transport and deposition. The technique has been applied in geoarchaeology. QHD provides a physical model for the development of other mineral dating techniques. The experimental protocol outlined in this study can be adopted for future studies.
DE: 9604 Cenozoic
DE: 5415 Erosion and weathering
DE: 3694 Instruments and techniques
DE: 3900 MINERAL PHYSICS
DE: 1035 Geochronology
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2004 AGU Fall Meeting