Zircon O- and Hf-isotope constraints on the genesis and tectonic significance of Permian magmatism in Patagonia

Castillo, Paula; Fanning, C. Mark; Pankhurst, Robert J.; Hervé, Francisco; Rapela, CarlosW.. 2017 Zircon O- and Hf-isotope constraints on the genesis and tectonic significance of Permian magmatism in Patagonia. Journal of the Geological Society, 174 (5). 803-816. https://doi.org/10.1144/jgs2016-152

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Official URL: https://doi.org/10.1144/jgs2016-152

Abstract/Summary

The genesis of Permian magmatism in southern South America is actively debated, particularly in relation to the origin of Patagonia. U–Pb zircon ages of c. 255 Ma for igneous rocks from the basement of Tierra del Fuego are the first evidence for southerly prolongation of this magmatism. Zircon in these rocks has εHft values <−1 and δ18O > 7.4‰, indicating recycling of Cambrian rocks. Permian granites in the north of the North Patagonian Massif record mantle-like δ18O magmatic input at c. 280 and 255 Ma, but reworking of upper crust between these two events, paralleling the recognized deformational history. In northwestern Patagonia, Early Permian granitic rocks have zircon with εHft values ranging from +0.1 to −7.2, and δ18O > 6.2‰, suggesting continuity of the Permian magmatic belt along the western margin of South America farther north. Comparison with a sample from the Sierra de la Ventana suggests melting of similar crust on both sides of the Patagonia–South American hypothetical suture. These features, together with other geological considerations, are consistent with an autochthonous or parautochthonous origin of northern Patagonia and connection between southern Patagonia and the Antarctic Peninsula in late Palaeozoic time. Supplementary material: U–Pb SHRIMP, O and Hf analytical data are available at https://doi.org/10.6084/m9.figshare.c.3768710

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1144/jgs2016-152
ISSN:	0016-7649
Date made live:	11 Sep 2017 15:06 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/517763

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1144/jgs2016-152

ISSN:

0016-7649

Date made live:

11 Sep 2017 15:06 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/517763