フィッション・トラック年代測定におけるエッチングの異方的効果について

概要

論文の詳細を見る
The pricise experiments on anisotropic etching efficiency in zircon, make clear the following points. 1. The rate of increase of track density and track length with etching time are controlled by crystallographic properties of zircon. 2. In the samples of low track density, such as young zircons, the effect of crystallographic orientation on track etching is extremely remarkable. This effect progressively decrease with the increase of spontaneous track density. 3. Track shape observed on SEM have a strongly preferred orientation. These points lead to the conclusion that the anisotropic track distribution is caused by the combination of three factors, the rate of etching a long a track (V_T), ground etching rate of zircon (V_G) and etching efficiency of selected etchant. The underestimated track density due to the anisotropic track distribution can be corrected by using the ideal track density calculated from the measurement of the distribution of number of tracks with azimuth. The corrected ages obtained from the external detector method represent good agreement with the previously reported K-Ar ages.
地学団体研究会の論文
1985-05-25