Track fading is a basic phenomenon in track science and has been the source of information in geosciences. This article summarizes the knowledge of track fading and gives some examples of successful applications of track fading in archaeology, tectonics and geothermal chronology in China. The applications of track fading are classified into 5 modes: (1) mode of complete fading (annealing); (2) mode of partial fading; (3) use of the dependence of track fading on time and temperature; (4) use of the differences of track fading between coexisting minerals; and (5) use of fading-reduced track length. Track fading mechanisms hints that scientists in geothermal chronology should adopt microprobes for quantitative elemental analysis to determine the detailed chemical compositions of each mineral grain or at least of the grains from each position of geological structures in order that one becomes well aware of the relation between the track fading behavior and chemical compositions of the mineral used.
Analyses of rare earth elements (REE) in gold-bearing quartz vein, granite and altered wall-rock (amphibolite) collected from Jiapigou gold belt in Southeast Jilin Province were conducted using inductively coupled plasma-mass-spectrometry (ICP-MS). The results in- dicated that the Jiapigou gold belt underwent two periods of gold mineralization: the earlier mineralization was related to the intrusion of Neoarchaean kaligranite, where the REE of earlier gold-bearing quartz veins and Neoarchaean kaligranites were typically featured by lower concentration and positive Eu anomaly; the later mineralization was related to the intrusion of the Yanshanian granite in Mesozoic, where the REE of later gold-bearing quartz veins and Yanshanian granites were typically featured by high concentration and negative Eu anomaly. However, the metallogenic mechanisms of the earlier and of the later gold mineralization periods were analogous, metallogenic materials were heterogenous with metallogenic fluids which mainly originated from magmatic hydrothermal fluids, mixed with metamorphic fluids; the metallogenic materials were mainly derived from the altered wall rock.
