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Jurassic cooling ages in Paleozoic to early Mesozoic granitoids of northeastern Patagonia: 40Ar/39Ar, 40K–40Ar mica and U–Pb zircon evidence
(Springer, 2016-12)
U–Pb SHRIMP zircon crystallization ages and Ar–Ar and K–Ar mica cooling ages for basement rocks of the Yaminué and Nahuel Niyeu areas in northeastern Patagonia are presented. Granitoids that cover the time span from ...
K-Ar age determinations of the late Tertiary and Quaternary Andean volcanic rocks, southern Peru
(The Geochemical Society of JapanJP, 1984)
K-Ar ages were determined on 30 Andean volcanic rocks from southern Peru, most of which were considered to belong to the Barroso Group of Quaternary in age. The results have revealed, however, that their ages range from ...
Ash-flow sheets of early Miocene and early Pliocene age are present in the Castillo de Callalli, Arequipa Department, southern Perú
(Sociedad Geológica del PerúPE, 2003-07)
Two ash-flow sheets of markedly different age and petrography are exposed in the Castillo de Callalli. The lower, phenocryst-rich ash-flow sheet of low-silica rhyolite has a K-Ar age of 20.7 -+ 0.6 Ma. The overlying ash-flow ...
Depositional age definition of the Açu Formation (Potiguar Basin, 40 39 northeastern Brazil) through Ar- Ar dating of early-authigenic K-feldspar overgrowthsDEFINIÇÃO DA IDADE DEPOSICIONAL DA FORMAÇÃO AÇU (BACIA POTIGUAR, NORDESTE DO BRASIL) 40 39 ATRAVÉS DA DATAÇÃO
(Instituto de Geociências /Universidade Federal do Rio Grande do Sul, 2010)