关键词: 裂变径迹年龄, 封闭径迹长度, 热史模拟

Abstract: Unlike most methods of radiometric dating, fission track dating measures the effect, rather than the products, of radioactive decay events. External detector dating method can calculate individual grain ages. There are three assembled ages for single sample, which are pooled age, mean age and central age. It is very important that the fission track ages have no unambiguous geological significance. Tracks are randomly oriented in three dimensional space. However, the measurements of track density used in age eterminations are based on a two dimensional sample of tracks intersecting an internal surface. With the increasing of the temperature, the fission tracks are progressively shortened from their ends, resulting in a reduction in the observed area density of the tracks and therefore a reduction in the measured fission track age. Because the fission track age is associated with the length of tracks, the length and distribution of tracks are the most important parameters in the fission track analysis. By modelling of thermal histories from apatite fission track data, the thermal histories of samples can be reconstructed.

Key words: fission track age, track length, modeling of thermal histories