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Thermoluminescence of annealed and shock-loaded feldspar

Thesis/Dissertation ·
OSTI ID:5553820

Samples of oligoclase and bytownite were shock-loaded to a variety of pressures, and annealed for a variety of temperatures and times. The effect of Mrad doses of gamma-rays on oligoclase TL were also studied. After these treatments, thermoluminescence (TL) and X-ray diffraction (XRD) measurements were made to: (1) determine the effects of shock on terrestrial feldspar and compare with variations in the TL emission of ordinary chondrites (OCs); (2) determine if disordering in feldspar was responsible for any related changes in TL properties of OCs; (3) determine if the combined effect of shock plus annealing causes the changes in TL properties; (4) see if radiation damage from cosmic ray exposure plays a role in the TL variations; (5) examine the implications of this work to the thermal and shock histories of OCs. The lightly shock-loaded and annealed oligoclase samples have a dominant peak temperature of 120-140 C, identical to type 3.3-3.5 OCs. The heavily shocked samples dominant peak is at 230C, similar to type > 3.5 OCs . While the heavily annealed/disordered oligoclase samples have a peak at 280C, this peak is rarely observed in OCs. Radiation damage from Mrad doses of gamma-rays produced no change in peak temperature, but facilitated the shift to higher peak temperatures. The TL sensitivity of the shocked samples decreased by a factor of 25. Samples annealed at low temperatures (438-533C) showed a factor of 2 decrease in TL, but at the highest temperatures, the TL was a factor of 8 higher.

Research Organization:
Arkansas Univ., Fayetteville, AR (USA)
OSTI ID:
5553820
Country of Publication:
United States
Language:
English