Geophysical investigation of the Navarino Island, plutons (Beagle Channel, Chile).

PERONI J. I,; TASSONE A.; LIPPAI, H,; HERVÉ, F.; MENICHETTI, M.; LODOLO E.

BOLLETTINO DI GEOFISICA TEORICA ED APPLICATA

ISTITUTO NAZIONALE DI OCEANOGRAFIA E DI GEOFISICA

Lugar: Trieste; Año: 2010 vol. 51 p. 114 - 117

0006-6729

In order to determine the geometry in depth of the Castores and Santa Rosa plutons, three magnetic, lithologic, and structural data campaigns were carried out between 2008 and 2010 in the area of Navarino and Hoste islands and in the Beagle Channel. Magnetic measurements were acquired with two magnetometer (EG&G Geometrics and a Scintrex Envi Grad). 72 hand-oriented samples were obtained in 13 sites for lithologic, paleomagnetic, magnetic susceptibility and AMS studies. Two intrusive bodies were modeled along the magnetic profile using the Encom ModelVision Pro 7.0 software (Encom Technology, 2002). The obtained model for Castores Pluton (Body 1, Figure 2) yielded an ellipsoidal body with a 2 km. vertical axis, E-W horizontal axis of 4.4 km. and N-S horizontal axis of 8 km. Given that the magnetic profile cuts across the northern margin of the Castores Pluton, the obtained modeled body represents only a lateral image of the whole intrusive body. The magnetic modeling of the Santa Rosa Pluton (Body 2, Figure 2) produced an overall oblated body with an average thickness of 1 km., with horizontal axis of 7.1 (E-W) and 4 km. (N-S). The A-B magnetic section with the obtained modeled plutonic bodies was combined with a DEM (SRTM30) and a MrSid satellite image (GeoCover Landsat – NASA) in Figure 3a which clearly  shows the topography and the outcrops of the studied plutons. The obtained modeled section provides a 2D picture of the uppermost  2 km of the crust of Navarino island viewed from the north