Reverse magnetic anomaly controlled by Permian Igneous rocks in the Iberian Chain (N Spain)

Authors

  • P. CALVIN Dpto. de Ciencias de la Tierra. Universidad de Zaragoza. C/Pedro Cerbuna, 12, 50009 Zaragoza, Spain. Dpto. de Física, Escuela Politécnica Superior, Universidad de Burgos. Avda. Cantabria, s/n, 09006 Burgos, Spain.
  • A.M. CASAS Dpto. de Ciencias de la Tierra. Universidad de Zaragoza. C/Pedro Cerbuna, 12, 50009 Zaragoza, Spain.
  • J. J. VILLALAÍN Dpto. de Física, Escuela Politécnica Superior, Universidad de Burgos. Avda. Cantabria, s/n, 09006 Burgos, Spain.
  • P. TIERZ Dpto. de Ciencias de la Tierra. Universidad de Zaragoza. C/Pedro Cerbuna, 12, 50009 Zaragoza, Spain. Instituto Nazionale di Geofisica e Vulcanologia, Sezione di Bologna. Via Donato Creti, 12, 40128 Bologna, Italy.

Keywords:

Reverse magnetic anomaly, Kiaman, Early Permian, 2.5D modelling, Paleomagnetic properties, Iberian Chain.

Abstract

Two important reverse dipolar magnetic anomalies in the Iberian Chain (Spain) are located over Permian igneous rocks. A detailed study of one of them, the Loscos magnetic anomaly, where the geological structure is well constrained, reveals that the source of the anomaly must be a reverse remanent magnetisation carried by igneous rocks, acquired during the period of the Kiaman reverse magnetic superchron. Magnetic and gravimetric detailed survey (with 50 new gravimetric measurements and 8 main magnetic profiles -six of them N–S and the rest E–Wwith a total length of 40km), together with a study of the petrophysical characteristics of igneous materials, data processing and interpretation (upward continuation, 2.5D modelling, etc.) allowed to characterize qualitatively the anomaly and its source. Two overlapping anomalies with different wavelength were identified, indicating the presence of a shallower strongly altered igneous body with heterogeneous magnetic properties, and a deeper, large igneous body, responsible for the main, long-wavelength anomaly.

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Published

2014-07-31

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