Incremental growth of the Patagonian Torres del Paine laccolith over 90 k.y.
Abstract
The Miocene Paine Granite in the Torres del Paine IntrusiveComplex, southern Chile, is an extraordinary example of an uppercrustal mafic and granitic intrusion. The granite intruded asa series of three sheets, each one underplating the previoussheet along the top of the basal Paine Mafic Complex. High-precisionU/Pb geochronology on single zircons using isotope dilution-thermalionization mass spectrometry yields distinct ages of 12.59 ±0.02 Ma and 12.50 ± 0.02 Ma, respectively, for the firstand last sheet of the laccolith. This age relationship is consistentwith field observations. The zircon ages define a time frameof 90 ± 40 k.y. for the emplacement of a >2000-m-thickgranite laccolith. These precise U-Pb zircon ages permit identificationof the pulses in a 20 k.y. range. The data obtained for thePaine Granite fill the gap between 100 k.y. and 100-1000yr pulses described in the literature for crustal magma chambers.
- Publication:
-
Geology
- Pub Date:
- June 2008
- DOI:
- 10.1130/G24546A.1
- Bibcode:
- 2008Geo....36..459M