3D Geophysic model of Ushuaia Pluton. Tierra del Fuego. Argentina.

PERONI J. I.; TASSONE A.; CERREDO M.E.; LIPPAI H.; MENICHETTI M.; LODOLO E.; ESTEBAN F.; VILAS J.F.

BOLLETTINO DI GEOFISICA TEORICA ED APPLICATA

ISTITUTO NAZIONALE DI OCEANOGRAFIA E DI GEOFISICA

Lugar: Trieste; Año: 2008 vol. 49 p. 262 - 267

0006-6729

The Ushuaia Pluton outcrops in the area of the homonym bay, to the south of the Isla grande de Tierra del Fuego. The pluton is emplazed, intruying and afecting sedimentary rocks ands black schists of the low Cretaceous Yahgán Fm, deformed by the Late Cretaceous Andean compression which afected the austral region of  South America. The pluton is afected by strike-slip and normals faults, asociated to the Beagle Channel Fault System. An aeromagnetic survey in the study area presents a positive magnetic anomaly of 70 km2. The contour lines range from 350 to -320 nT. On the basis of aeromagnetics and geophysics-geologics data obtain in the field, it has been developed for first time a three dimensions geophysic model of Ushuaia Pluton. This modeled body is composed of two dominants litologies, hornblendite and syenite, and displays a laccolithic form with a maximum thickness of 4000 m in its central area. To the borders the body thickness reduced, reaching 500 meters. On plant view, the body possess an oval shape with N-S major axis (around 12 km), E-W minor axis (10 km) and total volumen of 140 km3.