Petrology of the Proterozoic mafic dyke swarms of Uruguay and constraints on their mantle source composition

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• 作者：Mazzucchelli ; Maurizio ; Rivalenti ; Giorgio ; Piccirillo ; Enzo Michele ; Girardi ; Vicente Antonio Vitorio ; et. al.
• 刊名：Precambrian Research
• 出版年：1995
• 出版时间：August, 1995
• 年：1995
• 卷：74
• 期：3
• 页码：177-194
• 全文大小：1.17 M

文摘

Three dyke swarms in Uruguay range in age from Palaeoproterozoic (1.86 Ga, Florida region) to Neoproterozoic ( 0.7 Ga, Nico Perez and Treinta y Tres regions). The Florida and Nico Perez swarms are basalts, basaltic andesites and andesites with tholeiitic affinity, characterized by LILE and LREE enrichment with respect to HFSE, Nb depletion with respect to K and La, < 260, < 19, > 13, ()_n > 4.5. Both swarms have positive _Sr and negative _Nd, but the Florida isotopic array is dominated by _Nd variations (EM1 type) and that of Nico Perez by _Sr variation (EM2 type).