Palaeomagnetism and K-Ar dating of the Carboniferous Andacollo Series (Argentina) and the age of its hydrothermal overprinting
Palaeomagnetic data from 15 hand samples collected in a sequence of tuffs of Carboniferous age (Andacollo Series) exposed in western Argentina (37°10′S, 70°38′W) are given. These samples show hydrothermal alteration. After AF and thermal cleaning the majority of samples show reversed polarity and yi...
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| Autores principales: | , |
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| Formato: | JOUR |
| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_0012821X_v40_n1_p101_Vilas |
| Aporte de: |
| Sumario: | Palaeomagnetic data from 15 hand samples collected in a sequence of tuffs of Carboniferous age (Andacollo Series) exposed in western Argentina (37°10′S, 70°38′W) are given. These samples show hydrothermal alteration. After AF and thermal cleaning the majority of samples show reversed polarity and yield a palaeomagnetic pole at 73.6°S, 64.7°E (dψ = 6°, dχ = 9°). By comparing the position of this pole with the apparent polar wander curve recognized for the Late Palaeozoic and Mesozoic of South America, quantitative support for a Cretaceous age for the cleaned remanence of these samples is given. K-Ar dating of the Andacollo rocks indicates a mean age of 69 ± 4 m.y.; this suggests that the isotopic system of these rocks became closed in Late Cretaceous time. Palaeomagnetic and radiometric data agree indicating a Cretaceous age for the hydrothermal alteration of the Andacollo rocks. © 1978. |
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