info:eu-repo/semantics/article
Geophysical modeling and structure of Ushuaia Pluton, Fuegian Andes, Argentina
Fecha
2009-10Registro en:
Peroni, Javier Ignacio; Tassone, Alejandro Alberto; Menichetti, Marco; Cerredo, Maria Elena; Geophysical modeling and structure of Ushuaia Pluton, Fuegian Andes, Argentina; Elsevier Science; Tectonophysics; 476; 3-4; 10-2009; 436-449
0040-1951
CONICET Digital
CONICET
Autor
Peroni, Javier Ignacio
Tassone, Alejandro Alberto
Menichetti, Marco
Cerredo, Maria Elena
Resumen
Within the area of Ushuaia Bay (Tierra del Fuego, southernmost South America) the deformed Lower Cretaceous sedimentary rocks of Yahgán Formation host the Ushuaia Pluton. The intrusive body is oval in map view; it is compositionally varied with rocks ranging from the ultrabasic to the mesosiliceous realm. The emplacement time is constrained within the Albian-Cenomanian span by new amphibole K/Ar data. Meso- and microstructures of Ushuaia Pluton and its host indicate a synkinematic emplacement with a dominant extensional component. A set of transcurrent and normal faults related to the sinistral strike-slip Beagle Channel Fault System affects the pluton and its host. On the basis of aeromagnetic data combined with field information, a new model is presented for the Ushuaia Pluton. Modeling results fit well with a laccolithic body with an estimated volume of around 111 km3. The model pluton cross-section displays a central zone with an average thickness of 2000 m which progressively thins toward the margins (∼ 500 m) and a southern root which reaches 5000 m deep. The combined structural and geophysical model supports a transtensive scenario for the Ushuaia Pluton emplacement at Early-Late Cretaceous boundary.