The first SHRIMP U-Pb zircon ages from Catoca and Tchiuzo kimberlites, Angola

SANDRA E. ROBLES-CRUZ; MONICA ESCAYOLA; BILL DAVIS; SALVADOR GALÍ; MANUEL WATANGUA; JOAN CARLES MELGAREJO

Brasilia

Congreso; VII SSAGI South American Symposium on Isotope Geology; 2010

Universidade de Brasilia

The first SHRIMP U-Pb ages of Angolan Kimberlites, Catoca and Tchiuzo, which are located at the NE-SW Lucapa structure, are presented in this study. The first reference about age from Kimberlites in Angola was made by Bardet and Vachette (1966), who proposed a main Cretaceous kimberlitic event for Congo-Léo, formerly Angola (nowadays Democratic Congo Republic), based on stratigraphic relationships. Davis (1977) was the first who dated one zircon crystal, yielded an age of 134 Ma. Then Haggerty et al., (1983) carried out fission track dating of zircon from Val do Queve, reporting 133.4±11.5 Ma. In contrast, Egorov et al. (2007) reported K-Ar dating of phlogopite from kimberlite groundmass of 372±8 MA. Thirty-eight U-Pb analyses were carried out on 27 zircon crystals from Catoca and Tchiuzo kimberlites, using Sensitive High Resolution Ion Microprobe II (SHRIMP II), at the Laboratory of Geochronology of the Geological Survey of Canada. Cathodoluminescence (CL) images were used to characterize zircon. This new data shed light on the evolution of kimberlites in Angola. TRABAJO COMPLETO ADJUNTO