Datación U-Pb SHRIMP de circones detríticos en paranfibolitas neoproterozoicas de las secuencia Difunta Correa (Sierras Pampeanas Occidentales, Argentina)

The Neoproterozoic Difunta Correa meta-sedimentary sequence (DCSS) of Western Sierras Pampeanas is a cover to a rejuvenated Grenvillian basement. The Western Sierras Pampeanas are allegedly part of the exotic Precordillera Terrane, which was accreted to the proto-Andean margin of Gondwana in lower P...

Full description

Bibliographic Details
Authors: Rapela, Carlos W., Pankhurst, R.J., Casquet Martín, César, Fanning, C.M., Galindo Francisco, María Del Carmen, Baldo, Edgardo G.
Format: article
Publication Date:2005
Country:España
Institution:Universidad Complutense de Madrid (UCM)
Repository:Docta Complutense
Language:Spanish
OAI Identifier:oai:docta.ucm.es:20.500.14352/49427
Online Access:https://hdl.handle.net/20.500.14352/49427
Access Level:Open access
Keyword:550.4(238)
SHRIMP zircon dating
Neoproterozoic
Sierras Pampeanas
Argentina
Geoquímica
2503 Geoquímica
Description
Summary:The Neoproterozoic Difunta Correa meta-sedimentary sequence (DCSS) of Western Sierras Pampeanas is a cover to a rejuvenated Grenvillian basement. The Western Sierras Pampeanas are allegedly part of the exotic Precordillera Terrane, which was accreted to the proto-Andean margin of Gondwana in lower Palaeozoic times. A para-amphibolite from this sedimentary sequence contains abundant zircons mostly consisting 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 - Ordovician ages due to Pb-loss. Ages of igneous cores are ~ 625 Ma , 1050-1150 Ma and 1200-1500 Ma with a peak at c. 1.4 Ga. The ~ 625 Ma group zircon is of Gondwanan provenance and this age is an upper value for the age of the host amphibolite. An age between 580 Ma and 620 Ma is inferred for the DCSS. The provenance 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 considerations suggest 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.

Similar Items