Minerals characterization through materials science techniques: Font-Basin study of the Brazilian Bauru Group basin by fission track method, U/Pb and (U-Th-Sm)/He

• Grant number: 12/01919-5
• Support Opportunities: Scholarships abroad - Research
• Effective date (Start): August 23, 2012
• Effective date (End): August 22, 2013
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Carlos Alberto Tello Sáenz
• Grantee: Carlos Alberto Tello Sáenz
• Host Investigator: Ulrich Anton Glasmacher
• Host Institution: Faculdade de Ciências e Tecnologia (FCT). Universidade Estadual Paulista (UNESP). Campus de Presidente Prudente. Presidente Prudente , SP, Brazil
• Research place: Heidelberg University, Germany

Abstract

It is intended to study the effects of chemical etching in the minerals: apatite, zircon and epidote and their implications in the Fission-track Method (FTM). For that, a characterization of each one of these minerals will be performed through: i) Optical Microscopy; ii) micro-Raman spectroscopy; iii) Atomic Force Microscopy (AFM); iv) Heavy Ions Implantation and v) Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS). That way, we will have enough information to perform a theoretical-experimental study of the different physic-chemical phenomena which take place during the natural crystallization of each mineral, with the aim of determining the relationship between the chemical etching, utilized to develop the fission-tracks, and their crystallographic characteristics. The density of fission-tracks observed in the surface of grains from these minerals may vary due to natural alterations either of the grains' chemical composition or of its crystalline structure. In the case of the zircon and the epidote (and less frequently the apatite) it is observed that in some grains the density of fission-tracks is anisotropic, i.e., even in a single grain the density of tracks may vary across the grain surface. It may happen on account of the incorporation of other minerals during the crystallization period, which minerals we intend to identify and characterize. Therefore, these studies aim, in a general way, to give continuity to the improvement of the FTM in these minerals. These methodological advances will be utilized to determine both the age and the thermal history from the crystalines located at the Canastra Mountain Range, in the region of Passos and Franca, between the states of Minas Gerais and São Paulo. Additionally, the dating methods U/Pb (LA-ICP-MS) and (U-Th-Sm/He) will be respectively applied to the zircon and apatite grains collected in the Canastra Mountain Range. Thus, it will be simultaneously obtained a pool of ages via FTM, U/Pb and (U-Th-Sm/He) in the samples collected in the study area. It will allow to perform a broader geochronological study of the Bauru Group, through the comparison of the ages previously obtained in this geological unity with those obtained in the Canastra Mountain Range. I.e., it will be possible to perform a Font-Basin study since the region of the Canastra Mountain Range may have been an important source of sediments to the Bauru Group, located at the north of the Paraná Basin. To achieve this objective 20 samples are going to be collected in profiles previously established, favouring points located near geological faults.It is intended to perform this project in the period of 15/08/2012 to 15/08/2013, in collaboration with Prof. Dr. Ulrich A. Glasmacher, leader of the Research Group: "Thermochronology, Archeometry and Geochemistry", in the Institute of Earth Sciences, Ruprecht-Karls-University Heidelberg, Heidelberg - Germany. Prof. Dr. Glasmacher has all the equipments mentioned above. That way, this project becomes a continuation of the Projeto Jovem Pesquisador (Proc. FAPESP: 2005/51142-3, from 01/08/2008 to 31/07/2012) coordinated by the grant applicant. Thus, through the development of this project we are going to have the possibility of insert the (U-Th-Sm)/He methodology in our laboratory and that way our research group (through the flux of students at the level of scientific initiation, master's and doctorate degree, which could visit the laboratory of Prof. Glasmacher) will be giving a great step towards the enhance and consolidation of its internationalization. (AU)