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Time resolved construction of a bimodal laccolith (Torres del Paine, Patagonia)

Leuthold, Julien
Müntener, Othmar
Baumgartner, Lukas P.
Published in Earth and Planetary Science Letters. 2012, vol. 325-326, p. 85-92
Abstract Granitic and mafic magma pulses were sequentially accreted in the spectacularly exposed shallow crustal Torres del Paine laccolith, in southern Patagonia. This 12.5 Ma pluton forms a composite intrusion with a subvertical feeding system in the west and a laccolith in the east. A key unknown in the formation of sill complexes is how individual magma pulses are assembled over time and the geometry and localization of their feeding system. High resolution zircon CA-ID-TIMS U-Pb dating shows that the laccolith grew first by under-accretion of granitic sills over 90 +/- 30 ka, linked to a 'sheet-like' feeding system, followed by underplating of mafic sills after similar to 20 ka of quiescence. In the mafic sills complex, individual sills were injected by over-accretion during 41 +/- 11 ka. Our data show that successive granitic and mafic magmas emplacement generated a volume of similar to 88 km(3) in 162 +/- 11 ka. (C) 2012 Elsevier B.V. All rights reserved.
Keywords Granitic magmaEmplacementZirconChileCrystallizationMechanismsCaliforniaPlutons
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Research group Isotope Geochemistry, Geochronology and Thermochronology
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LEUTHOLD, Julien et al. Time resolved construction of a bimodal laccolith (Torres del Paine, Patagonia). In: Earth and Planetary Science Letters, 2012, vol. 325-326, p. 85-92. https://archive-ouverte.unige.ch/unige:21467

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Deposited on : 2012-06-04

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