Laurenzi, Marinella A.Balestrieri, Maria LauraBigazzi, GiulioNeto, Julio C. HadlerIunes, Pedro J.Norelli, PioOddone, MassimoOsorio Araya, Ana MariaViramonte, Jose G.2014-05-202014-05-202007-06-01Geostandards and Geoanalytical Research. Malden: Wiley-blackwell, v. 31, n. 2, p. 105-124, 2007.1639-4488http://hdl.handle.net/11449/6828New analyses have been performed in order to enhance the data-set on the independent ages of four glasses that have been proposed as reference materials for fission-track dating. The results are as follows. Moldavite - repeated (40)Ar/(39)Ar age determinations on samples from deposits from Bohemia and Moravia yielded an average of 14.34 +/- 0.08 Ma. This datum agrees with other recent determinations and is significantly younger than the (40)Ar/(39)Ar age of 15.21 +/- 0.15 Ma determined in the early 1980s. Macusanite (Peru) -four K-Ar ages ranging from 5.44 +/- 0.06 to 5.72 +/- 0.12 Ma have been published previously. New (40)Ar/(39)Ar ages gave an average of 5.12 +/- 0.04 Ma. Plateau fission-track ages determined using the IRMM-540 certified glass and U and Th thin films for neutron fluence measurements agree better with these new (40)Ar/(39)Ar ages than the previously published ages. Roccastrada glass (Italy) - a new (40)Ar/(39)Ar age, 2.45 +/- 0.04 Ma, is consistent with previous determinations. The Quiron obsidian (Argentina) is a recently discovered glass that has been proposed as an additional reference material for its high spontaneous track density (around 100 000 cm(-2)). Defects that might produce spurious tracks are virtually absent. An independent (40)Ar/(39)Ar age of 8.77 +/- 0.09 Ma was determined and is recommended for this glass. We believe that these materials, which will be distributed upon request to fission-track groups, will be very useful for testing system calibrations and experimental procedures.105-124engfission-track dating(40)Ar/(39)Ar datingnatural glassesage standardsArtigo10.1111/j.1751-908X.2007.00844.xWOS:000247205300004Acesso restrito1543738193935256