perature (21.0±0.5opIq rs tu vw u w" x tyztv {| yzu {}¤ x~}{} ux

摘要: METHODSWe prepared mounts of Fish Canyon Tuff apatite in petropoxy resin on glass in the usual manner. Internal surfaces of the apatites were exposed and polished. In order to reveal the fission tracks the two standard etchants, 7% HNO3 (aq) and 5N HNO3 (aq, were carefully prepared. The temperature of the etchants was controlled at 21.0±0.5 by immersing them in a thermostatically controlled water bath. Each mount was etched for a specific time followed by quenching in cold water for at least 30 minutes. For the