Zircon and apatite fission track method: chemical composition influence of apatite grains age

Abstract

The purpose of this project is to contribute in the continuation of the FTM (Fission Track Method) in apatite and zircon in the Fission Track Laboratory of DFQB/FCT- UNESP, Presidente Prudente. It is intended to determine the age of 5 zircon samples that have been collected in Bauru Group in Presidente Prudente region located in Bauru Group, São Paulo, Brazil.In the case of apatite will be measure the length and diameter of the tracks parallel to the crystallographic axis C , Dpar, in basal and prismatic faces of a single crystal sample, Durango apatite. In each crystallographic face, the following etches will be done: i) 5.5 M HNO3 , 20s , 25oC ; ii ) HNO3 , 1.6 M , 60s , 20 oC and iii ) HNO3 , 5M , 20s , 25oC. Through these experiments we can study the influence of chemical composition on the annealing phenomenon. With this, we can improve the annealing models, which are used to determine the thermal history of apatite.It is intended also to continue the characterization studies of the mineral apatite and zircon using micro-Raman measurements in 3 standard samples : Durango apatite, FCT ( Fish Canyon Tuff zircon ) and KGD (Kawamoto Granodiorite zircon). These characterizations are made before and after the natural diffusion of alpha particles in these minerals. Thus, it will be possible to study whether this diffusion significantly damage the crystal structure of these minerals. (AU)