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40Ar/39Ar dating of alunite from the pueblo viejo gold-silver district, Dominican Republic / Antonio Arribas in Economic geology, Vol. 106 N° 6 (Septembre/Octobre 2011) 

Public ISBD [article]  in Economic geology > Vol. 106 N° 6 (Septembre/Octobre 2011) . - pp. 1059-1070 Titre : 40Ar/39Ar dating of alunite from the pueblo viejo gold-silver district, Dominican Republic Type de document : texte imprimé Auteurs : Antonio Arribas, Auteur ; Isabel Arribas, Auteur ; Grenville Draper, Auteur Année de publication : 2011 Article en page(s) : pp. 1059-1070 Note générale : Géologie économique Langues : Anglais (eng) Mots-clés : Alunite  Gold-silver  district  Dominican  republic Index. décimale : 553 Géologie économique. Minérographie. Minéraux. Formation et gisements de minerais Résumé : New 40Ar/39Ar ages for alunite from the Moore and Monte Negro deposits in the Pueblo Viejo district, as well as from a newly discovered alunite-bearing zone on Loma la Cuaba west of the known deposits, are reported here. The ages range from about 80 to 40 Ma, with closely adjacent samples exhibiting very different ages. Interpretation of these results in the context of estimated closure temperatures for alunite and the geologic and tectonic evolution of Hispaniola does not lead to a simple conclusion about the age of mineralization. The simplest interpretation, that mineralization was caused by a buried Late Cretaceous (~80 Ma) intrusion, is complicated by lack of intrusions of this age in the area and absence of alteration in overlying limestone. The alternative interpretation, that mineralization was formed during Early Cretaceous (~110 Ma) magmatism and that the 40Ar/39Ar ages were completely reset by Late Cretaceous thrusting, is complicated by a lack of information on the timing and thermal effects of thrusting in central Hispaniola. Alunite studies have yielded similar unclear results in other pre-Cenozoic ore systems, notably those of the Lachlan fold belt in Australia. DEWEY : 553 ISSN : 0361-0128 En ligne : http://econgeol.geoscienceworld.org/content/106/6/1059.abstract [article] 40Ar/39Ar dating of alunite from the pueblo viejo gold-silver district, Dominican Republic [texte imprimé] / Antonio Arribas, Auteur ; Isabel Arribas, Auteur ; Grenville Draper, Auteur . - 2011 . - pp. 1059-1070. Géologie économique Langues : Anglais (eng) in Economic geology > Vol. 106 N° 6 (Septembre/Octobre 2011) . - pp. 1059-1070 Mots-clés : Alunite  Gold-silver  district  Dominican  republic Index. décimale : 553 Géologie économique. Minérographie. Minéraux. Formation et gisements de minerais Résumé : New 40Ar/39Ar ages for alunite from the Moore and Monte Negro deposits in the Pueblo Viejo district, as well as from a newly discovered alunite-bearing zone on Loma la Cuaba west of the known deposits, are reported here. The ages range from about 80 to 40 Ma, with closely adjacent samples exhibiting very different ages. Interpretation of these results in the context of estimated closure temperatures for alunite and the geologic and tectonic evolution of Hispaniola does not lead to a simple conclusion about the age of mineralization. The simplest interpretation, that mineralization was caused by a buried Late Cretaceous (~80 Ma) intrusion, is complicated by lack of intrusions of this age in the area and absence of alteration in overlying limestone. The alternative interpretation, that mineralization was formed during Early Cretaceous (~110 Ma) magmatism and that the 40Ar/39Ar ages were completely reset by Late Cretaceous thrusting, is complicated by a lack of information on the timing and thermal effects of thrusting in central Hispaniola. Alunite studies have yielded similar unclear results in other pre-Cenozoic ore systems, notably those of the Lachlan fold belt in Australia. DEWEY : 553 ISSN : 0361-0128 En ligne : http://econgeol.geoscienceworld.org/content/106/6/1059.abstract