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Classificação de algumas amostras de tectitos do Museu Nacional, Rio de Janeiro, pelo método de traços de fissão

2005; Sociedade Brasileira de Geologia; Volume: 35; Issue: 2 Linguagem: Inglês

10.5327/rbg.v35i2.1166

2317-4889

Ariadne do Carmo Fonseca, G. Bigazzi, Maria Elizabeth Zucoloto, P. Norelli,

Paleontology and Stratigraphy of Fossils

In the collection of tektites of the National Museum of the Federal University of Rio de Janeiro (Brazil) some samples classified as Moldavites showed morphological characteristics and a dark colour which made rather unconvincing this classification. Moreover, another sample classified as Indochinite showed very similar characteristics. Tektites from the various strewn fields have different ages. For this reason splits from these tektites were analysed using the fission-track dating method, in order to check whether their classification was correct. Four samples yielded fission-track ages between 0.6 and 0.7 Ma, which agree with the age of the Australasian tektites. Another sample yielded an age of 32.5 Ma, which indicates that this tektite belongs to the Bediasites and Georgia tehtites group (SE U.S.A.). None of the analysed samples is a Moldavite, considering that this central European tektite has an age of ~ 15 Ma.