ID-TMS U-Pb dating of baddeleyites from the Florianópolis dyke swarm

Abstract

This project aims to obtain high precision isotopic and geochronological data still unpublished for the Paraná-Etendeka Magmatic Province. The compositional and structural diversity of the dykes located between Florianópolis and Garopaba (SC) has been focus of field, petrography, electronic microscopy, whole rock geochemistry and Sr-Nd-Pb isotopes studies that complement previous studies and should be, whenever possible, incorporated to the data and samples existent. The age and extent of the Florianópolis Dyke Swarm tholeiitic magmatism, Paraná-Etendeka Magmatic Province, will be precisely determined by baddeleyite and zircon U-Pb ID-TIMS dating that will be done in University of Alberta, Edmonton, Canada, with Dr. Larry M. Heaman supervision. Based on these results, the parental magmas generation and evolution will be identified and, in favorable cases, they will be quantified. Therefore, will be possible to investigate: (1) the correlation between dykes and the lavas potentially fed by them and (2) the eventual affect of modifying process of magmas (e.g. fractional crystallization, magma mixing and crustal assimilation) and its disturbance in the isotopic systems (e.g., Ar-Ar, Rb-Sr). The results of these two lines of approach will give important support to constrain the precise ages of the dykes, refine the calibration between distinct dating methods and elucidate the magmatic processes involved in the PEMP magmas generation. (AU)