IGEBA   23946
INSTITUTO DE GEOCIENCIAS BASICAS, APLICADAS Y AMBIENTALES DE BUENOS AIRES
Unidad Ejecutora - UE
artículos
Título:
Permian remagnetization of the Early Cambrian Guachos Formation, Eastern Cordillera, Argentina
Autor/es:
FRANCESCHINIS, PABLO R.; ESCAYOLA, MÓNICA P.; FRANCESCHINIS, PABLO R.; ESCAYOLA, MÓNICA P.; RAPALINI, AUGUSTO E.; RODRIGUEZ PICEDA CONSTANZA; RAPALINI, AUGUSTO E.; RODRIGUEZ PICEDA CONSTANZA; FAZZITO, SABRINA Y.; GEUNA E. SILVANA; FAZZITO, SABRINA Y.; GEUNA E. SILVANA
Revista:
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Año: 2020 p. 1 - 13
ISSN:
0895-9811
Resumen:
The Permian remagnetization belt that affects the southwestern margin of Gondwana has an importantgeographic extension reaching several South American cratons and terranes. A paleomagnetic pole for the EarlyCambrian Guachos Formation in the Eastern Cordillera of Argentina was computed (LG: Lat: 58.1◦S, Long:20.2◦E, A95: 6.4◦, n: 30), that likely corresponds to a Permian remagnetization and suggests that such belt mightextend further north than previously envisaged. We performed several rock-magnetic studies on this successionof laminated fine grain sandstones and siltstones in order to determine the magnetic phases that carry theremanence. Thermomagnetic (k vs. T) curves, field and frequency dependence of bulk susceptibility, hysteresisloops, isothermal remanent magnetization acquisition and back-field curves, three-axis IRM thermal demagnetization,among others, permitted to establish magnetite as the main mineral carrying the remanence. Microscopicobservations confirmed a secondary chemical origin for magnetite. Magnetic fabric studies indicate atectonic fabric, consistent with cleavage developed on these rocks together with low-grade metamorphism.However, a Permian remagnetization, as suggested by the paleomagnetic pole position, cannot be related toCambrian deformation and metamorphism and might be related to hydrothermal processes.