Evolution history of the crust underlying Cerro Pampa, Argentine Patagonia: Constraint from LA-ICPMS U-Pb ages for exotic zircons in the Mid-Miocene adakite

Abstract

mas, the original crystallisation age can be preserved in a crystal core. A small domain of single zircon crystal can be dated in-situ using a sensitive high-resolution ionmicroprobe (SHRIMP) (e.g., Compston et al., 1984; Black et al., 1986) or laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) (e.g., Hirata and Nesbitt, 1995; Jackson et al., 2004; Kimura et al., 2011). The corresponding age distribution of zircons provides a fingerprint for the growth and recycling history of the continental crusts. Goldstein et al. (1997) presented an age population histogram for detrital zircon grains collected from the outlet of the Orinoco River in South America, and demonstrated that 49 SHRIMP U-Pb age fingerprints reveals the evolutionary history of the crust exposed in the wa

Geomorphic Records along the General Carrera (Chile)–Buenos Aires (Argentina) Glacial Lake (46°–48°S), Climate Inferences, and Glacial Rebound for the Past 7–9 ka

“…The GCBA Lake area is slab-free (Gorring and Kay, 2001;Gorring et al, 1997). Plio-Pleistocene basalts that erupted along this area at the Meseta del Lago Buenos-Aires provide evidence for asthenosphere-lithosphere interaction during slab window development (Orihashi et al, 2013;Guivel et al, 2006;Gorring et al, 2003;Gorring and Kay, 2001). This situation has an impact on the mechanical strength properties of the Patagonia lithosphere and upper mantle that in turn must induce a signature on the rate of vertical crustal motion (rebound) associated with ice mass loss.…”

Shallow-depth melt eduction due to ridge subduction: LA-ICPMS U-Pb igneous and detrital zircon ages from the Chile Triple Junction and the Taitao Peninsula, Chilean Patagonia

“…Hudson Volcano in the southernmost SVZ marks the location of the back-arc side of the MiocenePliocene magmatism. To the south, Miocene plutonism extends into the fore-arc region, and another chain of Middle to Late Miocene plutonism and Miocene adakitic magmatism (Kay et al, 1993;Ramos et al, 2004;Orihashi et al, 2013) appears behind the active volcanoes of the AVZ. Together with the Patagonian Volcanic Fields in the extra back-arc side, this area provides a good opportunity to study both along-arc and across-arc variation of magmas that are spatially and temporally constrained (Stern et al, 1990;Ramos and Kay, 1992;Kay et al, 1993;Gorring et al, 1997).…”

Preface: Geoscience dynamics in the Patagonia Archipelago^|^mdash;Southern Pacific Ocean

“…Based on the result of microanalysis for the clinopyroxene, the mantle xenoliths were of fertile peridotites, formed by melt extraction up to 13% having a primitive mantle composition since the Proterozoic age, which was only affected subordinately by the metasomatic overprint of hydrous basaltic melt accompanied with Neogene back-arc volcanism. Orihashi et al (2013) discovered numerous zircon xenocrysts in a Middle Miocene adakitic body in Cerro Pampa, Argentina, and used them to infer the evolutionary history of the underlying crust. Their results provide concrete evidence that supports a young growth history of the Patagonian continental crust, started at the Gondowana margins in the Paleozoic and continued to the beginning of Late Cretaceous.…”