IGEBA   23946
INSTITUTO DE GEOCIENCIAS BASICAS, APLICADAS Y AMBIENTALES DE BUENOS AIRES
Unidad Ejecutora - UE
artículos
Título:
Paleomagnetic evidence of earliest Paleocene deformation in Calama (~22°S), northern Chile: Andean-type or ridge-collision tectonics?
Autor/es:
SOMOZA, R., TOMLINSON, A., CAFFE, P.J., VILAS, J.F.
Revista:
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Lugar: Amsterdam; Año: 2012 vol. 37 p. 208 - 213
ISSN:
0895-9811
Resumen:
A paleomagnetic study from the earliest Paleocene Cerros de Montecristo
Quartz Monzonite and its Jurassic to uppermost Cretaceous host rock
(northern Chile, ∼22°S) provided high-temperature, high-coercivity
magnetizations of dominantly reversed polarity. The remanences of the
tilted host rock gave a negative fold-test and are indistinguishable
from the remanences found in the pluton, indicating that the uppermost
Cretaceous rocks underwent deformation before intrusion of the earliest
Paleocene pluton, thus documenting a KT deformation at the locality.
Although this deformation may be another product of typical
subduction-related noncollisional tectonics in the Central Andes, an
alternative hypothesis, permitted by plate reconstructions, is that the
event was associated with collision of an oceanic plate boundary. This
latter hypothesis may also provide a context for several other tectonic
events from northern Chile to the Patagonian Andes, wherein deformation
would the consequence of a southward migrating triple junction between
the latest Maastrichtian and Early Eocene.