Raman Spectroscopy and Scanning Electron Microscopy Characterizations of Fission Track Method Datable Zircon Grains


Autoria(s): Resende, Rosana Silveira; Tello Saenz, Carlos Alberto; Campos Curvo, Eduardo Augusto; Leopoldo Constantino, Carlos Jose; Aroca, Ricardo F.; Nakasuga, Wagner Massayuki
Contribuinte(s)

Universidade Estadual Paulista (UNESP)

Data(s)

03/12/2014

03/12/2014

01/05/2014

Resumo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Spectroscopic and morphological studies, designed to improve our understanding of the physicochemical phenomena that occur during zircon crystallization, are presented. The zircon fission track method (ZFTM) is used routinely in various laboratories around the world; however, there are some methodological difficulties needing attention. Depending on the surface fission track density observed under an optical microscope, the zircon grain surfaces are classified as homogeneous, heterogeneous, hybrid, or anomalous. In this study, zircon grain surfaces are characterized using complementary techniques such as optical microscopy (OM), micro-Raman spectroscopy, and scanning electron microscopy (SEM), both before and after chemical etching. Our results suggest that anomalous grains have subfamilies and that etching anisotropy related to heterogeneous grains is due to different crystallographic faces within the same polished surface that cannot be observed under an optical microscope. The improved methodology was used to determine the zircon fission track ages of samples collected from the Bauru Group located in the north of Parana Basin, Brazil. A total of 514 zircon grains were analyzed, consisting of 10% homogeneous, about 10% heterogeneous, about 20% hybrid, and 60% anomalous grains. These results show that the age distributions obtained for homogeneous, heterogeneous, and hybrid grains are both statistically and geologically compatible.

Formato

549-556

Identificador

http://dx.doi.org/10.1366/13-07302

Applied Spectroscopy. Frederick: Soc Applied Spectroscopy, v. 68, n. 5, p. 549-556, 2014.

0003-7028

http://hdl.handle.net/11449/113388

10.1366/13-07302

WOS:000335295400006

Idioma(s)

eng

Publicador

Soc Applied Spectroscopy

Relação

Applied Spectroscopy

Direitos

closedAccess

Palavras-Chave #Zircon #Micro-Raman spectroscopy #Fission track method #Scanning electron microscopy #SEM #Zircon grain surface characterization #Zircon chemical etching
Tipo

info:eu-repo/semantics/article