Artículo de revista
Teleseismic tomography of the southern Puna plateau in Argentina and adjacent regions
Fecha
2013Registro en:
Tectonophysics 586 (2013) 65–83
DOI: 10.1016/j.tecto.2012.11.016
Autor
Bianchi, M.
Heit, B.
Jakovlev, A.
Yuan, X.
Kay, S. M.
Sandvol, E.
Alonso, R. N.
Coira, E.
Brown, L.
Kind, R.
Comte Selman, Diana
Institución
Resumen
We performed a teleseismic P wave tomography study using seismic events at both teleseismic and regional
distances, recorded by a temporary seismic array in the Argentine Puna Plateau and adjacent regions. The
tomographic images show the presence of a number of positive and negative anomalies in a depth range
of 20–300 km beneath the array. The most prominent of these anomalies corresponds to a low-velocity
body, located in the crust, most clearly seen in the center of the array (27°S, 67°W) between the Cerro
Peinado volcano, the Cerro Blanco caldera and the Farallon Negro in the east. This anomaly (southern Puna
Magmatic Body) extends from the northern most part of the array and follows the line with the highest
density of stations towards the south where it becomes smaller. It is flanked by high velocities on the west
and the east respectively. On the west, the high velocities might be related to the subducted Nazca plate.
On the northeast the high velocity block coincides with the position of the Hombre Muerto basin in the
crust and could be indicating an area of lithospheric delamination where we detected a high velocity block
at 100 km depth on the eastern border of the Puna plateau, north of Galan. This block might be related to
a delamination event in an area with a thick crust of Paleozoic metamorphic rocks at the border between
Puna and Eastern Cordillera. In the center of the array the Southern Puna magmatic body is also flanked by
high velocities but the most prominent region is located on the east and is interpreted as part of the Sierras
Pampeanas lithosphere with high velocities. The position of the Sierras Pampeanas geological province is key
in this area as it appears to limit the extension of the plateau towards the south.