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A palaeomagnetic analysis of Miocene fluvial sediments at Pertusa, near Huesca, Ebro Basin, Spain

Published online by Cambridge University Press:  01 May 2009

P. Turner ,
J. P. P. Hirst  and
P. F. Friend
P. Turner
Affiliation:
Department of Geological Sciences, University of Aston, Gosta Green, Birmingham, U.K.
J. P. P. Hirst
Affiliation:
Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, U.K.
P. F. Friend
Affiliation:
Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, U.K.
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Abstract

In the Miocene fluvial system of the Huesca area, in the Ebro Basin, northern Spain, rivers radiated outwards, to the south and west, from a small sector of the northern margin of the basin. The deposits of the system extend about 60 km radially from this sector and then pass into calcareous and gypsiferous deposits.

The magnetostratigraphy of two logged sections, 1 km apart, within this system consists of an upper zone of normal polarity and a lower zone of reversed polarity. The lithostratigraphy and magnetostratigraphy are parallel.

The sands and silts are dominated by angular quartz, intraformational clay lithograins and calcite lithograins. They are mainly pale yellow brown to dusky yellow, and magnetic tests indicate that the magnetization is carried dominantly by ferric oxyhydroxides (haematite and gôethite). The higher temperature Natural Remanent Magnetization is probably due to detrital haematite which would have been partially aligned during fluvial deposition. Post-depositional modification (PDRM) may have occurred during dewatering.

Haematite pseudomorphing pyrite framboids indicates that early reducing conditions were succeeded by a more oxidizing regime which produced secondary magnetizations associated with fine-grained haematite and goethite.

Complete polarity zones are not delineated, but the thicknesses present are not excessive compared with other continental Miocene deposits. The average palaeolatitude of 22° is lower than would be expected for the Miocene of northern Spain, probably due to incomplete averaging of secular variations and other sources of error including possible ‘inclination error’.

Type
Articles
Information
Geological Magazine , Volume 121 , Issue 4 , July 1984 , pp. 279 - 290
Copyright
Copyright © Cambridge University Press 1984

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References

Allen, P. A., & Matter, A., 1982. Oligocene meandering stream sedimentation in the eastern Ebro Basin, Spain. Eclogae Geologicae Hehetiae 75, 33–49.Google Scholar
Allen, P. A., Cabrera, L., Colombo, F., & Matter, A., 1983. Variations in fluvial style on the Eocene-Oligocene alluvial fan of the Scala Dei Group, S.E. Ebro Basin (Spain). Journal of the Geological Society of London 140, 133–46.CrossRefGoogle Scholar
Barghorn, S., 1981. Magnetic-polarity stratigraphy of the Miocene type Tesuque Formation, Santa Fe Group, in the Española Valley, New Mexico. Bulletin of the Geological Society of America 92, 1027–41.2.0.CO;2>CrossRefGoogle Scholar
Behrensmeyer, A. K., & Tauxe, L., 1982. Isochronous fluvial systems in Miocene deposits of northern Pakistan. Sedimentology 29, 331–52.CrossRefGoogle Scholar
Butler, R. F., & Opdyke, N. D., 1979. Magnetic polarity stratigraphy. Reviews of Geophysics and Space Physics 17, 235–44.CrossRefGoogle Scholar
Crusafont, M., Riba, O., & Villena, J., 1966. Nota preliminar sobre un nuevo yacimiento de vertebrados Aquitanienses en Santa Cilia (Rio Formiga; Provincia de Huesca) y sus consequencias geologicas. Notas y Comunicaciones del Instituto de Geologico y Minero de España 83, 7–14.Google Scholar
Czyscinski, K. S., Byrnes, J. B., & Pedlow, G. W. III,. 1978. In situ red bed development by the oxidation of authigenic pyrite in a coastal depositional environment. Palaeogeography, Palaeoclimatology, Palaeoecology 24, 239–46.CrossRefGoogle Scholar
Dunlop, D. J., 1972. Magnetic mineralogy of unheated and heated red sediments by coercivity spectrum analysis. Geophysical Journal. Royal Astronomical Society London 27, 37–55.CrossRefGoogle Scholar
Friend, P. F., 1978. Distinctive features of some ancient river systems. In Fluvial Sedimentology (ed. Miall, A. D.), pp. 531–42. Canadian Society of Petroleum Geologists, Memoir 5.Google Scholar
Friend, P. F., Slater, M. J., & Williams, R. C., 1979. Vertical and lateral building of river sandstone bodies, Ebro Basin, Spain. Journal of the Geological Society of London 136, 39–46.CrossRefGoogle Scholar
Griffiths, D. H., King, R. F., Rees, A. I., & Wright, A. E., 1960. Remanent magnetism of some recent varved sediments. Proceedings of the Royal Society of London A 256, 359–83.Google Scholar
Instituto Geologico y Minero de Espana. 1977. Mapa tectonico de la Peninsula Iberica y Baleares, 1:1000 000. Madrid.Google Scholar
Molyneux, L., 1971. A Complete result magnetometer for measuring the remanent magnetisation of rocks. Geophysical Journal. Royal Astronomical Society, London 24, 429–33.CrossRefGoogle Scholar
Pardo, G., & Villena, J., 1979. Aportacion a la geologica de la region de Barbastro. Acta Geologica Hispanica (Homentage a Lluis Sole i Sabaris) 14, 289–92.Google Scholar
Puigdefabregas, C., 1973. Miocene point-bar deposits in the Ebro Basin, northern Spain. Sedimentology 20, 133–44.CrossRefGoogle Scholar
Riba, O., & Reguant, S., (in press). Ensayo de sintesis estratigrafica y evolutiva de la Cuenca Terciaria del Ebro. In Libro Homenaje a don Jose M. Rios, vol. II. Instituto de Geologico y Minero de Espana.Google Scholar
Riba, O., Villena, J. J., & Quirantes, J., 1967. Nota preliminar sobre la sedimentation en palaeocanales terciarios de la zona Caspe-Chiprana, (Provincia de Zaragoza). Anales de Edafologia y Agrobiologia 26, 617–34.Google Scholar
Smith, A. G., Hurley, A. M., & Briden, J. C., 1981. Phanerozoic paleocontinental world maps. Cambridge University Press. 102 pp.Google Scholar
Valet, J. P., & Laj, C., 1981. Paleomagnetic record of two succesive Miocene geomagnetic reversals in Western Crete. Earth and Planetary Science Letters 54, 53–63.CrossRefGoogle Scholar
Verosub, K. L., 1977. Depositional and post-depositional processes in the magnetisation of sediments. Reviews of Geophysics and Space Physics 15, 129–43.CrossRefGoogle Scholar
Widdowson, J. W., & de Sa, A., 1975. A digitally controlled AF demagnetiser for peak fields of up to 0.1 T. Journal of Physics, London E 8, 302–4.Google Scholar