%0 Journal Article
%A Rapela, Carlos W.
%A Pankhurst, R.J.
%A Casquet Martín, César
%A Fanning, C.M.
%A Galindo Francisco, María Del Carmen
%A Baldo, Edgardo G.
%T Datación U-Pb SHRIMP de circones detríticos en paranfibolitasneoproterozoicas de las secuencia Difunta Correa (SierrasPampeanas Occidentales, Argentina)
%D 2005
%@ 0213-683X
%U https://hdl.handle.net/20.500.14352/49427
%X The Neoproterozoic Difunta Correa meta-sedimentary sequence (DCSS) of Western Sierras Pampeanas isa cover to a rejuvenated Grenvillian basement. The Western Sierras Pampeanas are allegedly part of theexotic Precordillera Terrane, which was accreted to the proto-Andean margin of Gondwana in lowerPalaeozoic times. A para-amphibolite from this sedimentary sequence contains abundant zircons mostlyconsisting of detrital igneous cores with a metamorphic overgrowth. The latter formed at 439±34 Ma,i.e., during the Famatinian orogeny, although mantles are also found with mixed Grenvillian - Ordovicianages due to Pb-loss. Ages of igneous cores are ~ 625 Ma , 1050-1150 Ma and 1200-1500 Ma with a peakat c. 1.4 Ga. The ~ 625 Ma group zircon is of Gondwanan provenance and this age is an upper value forthe age of the host amphibolite. An age between 580 Ma and 620 Ma is inferred for the DCSS. Theprovenance of zircons between 1.05 Ga and c. 1.2 Ga probably lies in the underlying Grenvillian basement.However zircons older than 1.2 Ga were derived from an unexposed area: palaeogeographical considerationssuggest that this area could be either in Laurentia (trans-Laurentia belt) or in southern Amazonia (Rondonia-San Ignacio belt), both 1.3-1.5 Ga in age.
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