Cretaceous arc volcanism of Palmer Land, Antarctic Peninsula: Zircon U-Pb geochronology. geochemistry, distribution and field relationships

Riley, Teal R. ORCID: https://orcid.org/0000-0002-3333-5021; Flowerdew, Michael J.; Burton-Johnson, Alex ORCID: https://orcid.org/0000-0003-2208-0075; Leat, Philip T.; Millar, Ian L.; Whitehouse, Martin J.. 2020 Cretaceous arc volcanism of Palmer Land, Antarctic Peninsula: Zircon U-Pb geochronology. geochemistry, distribution and field relationships. Journal of Volcanology and Geothermal Research, 401, 106969. https://doi.org/10.1016/j.jvolgeores.2020.106969

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Abstract/Summary

The Cretaceous marks an episode of enhanced magmatism, sedimentation and tectonic processes along the entire proto-Pacific convergent margin of West Gondwana. Cretaceous magmatism across the Antarctic Peninsula is dominated by the intrusive Lassiter Coast intrusive suite which developed as episodic ‘flare-up’ events during the mid-Cretaceous, at a time of increased convergence. Volcanic rocks of this age are poorly defined, as a consequence of limited field observations and an absence of accurate geochronology. Recent field mapping, combined with unpublished field observations has identified a region >10,000 km2 of dominantly subaerial rhyolitic pyroclastic and epiclastic successions from northern Palmer Land of the Antarctic Peninsula. Volcanic successions up to 1500 m in thickness consist of dominantly silicic ignimbrites, lavas, heterolithic breccias and lahar deposits, fed by caldera-forming eruptions. The volcanic rocks of this region were widely considered to be Early Cretaceous in age based on field relationships and early geochronology. New U-Pb zircon ages identify three distinct volcanic episodes during the Late Cretaceous/Early Cenozoic at ~108 Ma, ~93 Ma and ~64 Ma. Lu-Hf data indicate significant proportions of ancient crust in the petrogenesis of the volcanic rocks and the slightly negative εHf values are consistent with a mid-position (~120 km) within the magmatic arc, relative to more juvenile compositions close to the trench.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1016/j.jvolgeores.2020.106969
ISSN:	0377-0273
Additional Keywords:	Gondwana; rhyolite; ignimbrite; volcanic; Hafnium
Date made live:	24 Jun 2020 09:29 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/527552

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