Crystallographic and isotopic characterization of the zircon mineral Peixe, Tocantins, Brazil, to use as age standard for the Fission Track Method

Abstract

It is intended to characterize the zircon mineral Peixe which are single crystals collected in the southern region of the state of Tocantins, Brazil, through different techniques such as micro Raman spectrometry and SEM to study details of its crystalline structure. These characterizations will be carried out before and after the chemical attack used to reveal the fission traces in this mineral. We will then apply the Fission Track Method, FTM, to determine both its age and its thermal history. Given that this single crystal has dimensions of approximately 1 cm, we will cut it into its different faces in order to observe whether the track density has anisotropic behavior. We will do the same by reducing part of the monocrystal into grains with random crystallographic orientations to determine the age of Fission Tracks, FT. Thus, these studies will make it possible to determine whether this sample can be used as an age standard for the MTF in a Brazilian sample. The FT Dating Method will be performed using a mass spectrometer (LA-ICP-MS) both in the grains and in the sections in different crystallographic planes. Thus, the age will be simultaneously obtained via MTF and the isotopic characterization of this sample, which can serve as a standard. Previously, two internationally recognized standard samples will be dated, the Fish Canyon Tuff, FCT, and the KGD (Kawamoto Granodiorite from Japan).