Abstract
Los Leones Granite represents a calc-alkaline tonalite-granodiorite tabular stock of ∼3 km2 intruded within Paleozoic metasedimentary rocks from the Eastern Andean Metamorphic Complex. Two newly obtained zircon SHRIMP U-Pb ages reveal a Middle Mississippian (340-335 Ma) crystallization age, contrasting with previously accepted K-Ar Pennsylvanian age. Isotopic analysis indicate derivation from a depleted source with minimal influence of continental crust contamination (eHf(i) ∼14), which experienced hydrothermal alteration at high temperatures (δ18O ∼4.13). New data coupled with contemporaneous subduction-related rocks in Western Patagonia and Antarctica suggest the existence a broader Lower Carboniferous subduction zone extending at least from Northern Patagonia, to Western Antarctica. On the other hand, isotopic signatures depict a tectono-magmatic framework with a thermal configuration of the margin that was modified by the presence of a local slab tear or the progressive horizontalization of the isotherms as result of the ∼20 myr. of magmatic quiescence in the area.
Original language | English |
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Article number | 105174 |
Journal | Journal of South American Earth Sciences |
Volume | 148 |
DOIs | |
Publication status | Published - 15 Nov 2024 |
Keywords
- Gondwanide magmatism
- O-Hf isotopes
- Patagonia
- U-Pb geochronology
ASJC Scopus subject areas
- Geology
- Earth-Surface Processes