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Volume 58 Supplement 10

Special Issue: Paleomagnetism and Tectonics in Latinamerica

Paleomagnetism of the late Cenozoic basalts from northern Patagonia

Earth, Planets and Space volume 58, pages 1273–1281 (2006)Cite this article

Abstract

Late Cenozoic volcanic rocks outcrop in the northern Patagonia Extrandina. Lava flows, characterized as olivine and alkaline basalts, belong to intraplate volcanism. We report paleomagnetic and rock-magnetic studies carried out on Late Cenozoic basalts belonging to the Cráter, Mojón and Moreniyeu Formations. The paleomagnetic sampling comprised 75 sites in lava flows and dikes from the Cráter Formation, three sites in a lava flow from the Mojón Formation and three sites in a lava flow from the Moreniyeu Formation. Alternating field (AF) and thermal detailed demagnetization techniques were used. Most of the samples have a viscous component. The AF procedure was more effective than thermal demagnetization in destroying viscous components and in defining the characteristic remanent magnetizations. Demagnetization curves and rock-magnetic studies suggest that the main remanence carrier is Ti-poor magnetite. Radiometric K-Ar ages were performed on these basalts. The radiometric ages are 0.8±0.1 Ma from outcrops located at Cerro Fermín and 1.9±0.4 Ma from outcrops at Cerro Negro, both at the Cráter Formation. These ages suggest an early-middle Pleistocene age for the lava flows from Cerro Fermín, and a late Pliocene to early Pleistocene age for the Cerro Negro lava flows. Based on the magnetic polarity temporal scale, the Cerro Fermín lava flows have registered the beginning of the Brunhes Chron, while the Cerro Negro basalts could have been extruded during the Olduvai Subchron. The K-Ar radiometric age of the Moreniyeu Formation (1.6±0.2 Ma) suggests an early Pleistocene age for this lava flow. The reverse polarity of its virtual geomagnetic poles (VGPs) is in agreement with the predominant one during the Matuyama Chron and suggests that the Moreniyeu Formation constitutes another volcanic event clearly separate from those of the Cráter Formation. The K-Ar radiometric age of the Mojón Formation (3.3±0.4 Ma) locates it in the middle Pliocene. The VGP polarity would be correlated with some reverse subchron located in Gauss Chron or with the end of the Gilbert Chron. The petrographical and geochemical similarities between the studied basalt and the Somuncura plateau basalts (late Oligocene-early Miocene, located northern and eastern of the study area), together with the time lapsed among between the Mojón and Cráter basalt extrusion suggest the presence in the area of a temporarily extensive thermal anomalies.

References

  • Baraldo, A., A. E. Rapalini, H. Bohnel, and M. Mena, Paleomagnetic study of Deception Island, South Shetland Islands, Antarctica, Geophys. J. Int., 153, 1–11, 2003.

    Article  Google Scholar 

  • Brown, L. L., B. S. Singer, and M. L. Gorring, Paleomagnetism and 40Ar/39Ar chronology of lavas from Meseta del Lago Buenos Aires, Patagonia, Geochem. Geophys. Geosystems, 5, Q01H04, doi:10.1029/ 2003GC000526, 2004.

    Article  Google Scholar 

  • Cande, S. and D. Kent, A new geomagnetic polarity time scale for the Late Cretaceous and Cenozoic, J. Geophys. Res, 97(B10), 13,917–13,951, 1995.

    Article  Google Scholar 

  • Coira, B., M. Franchi, and F. Nullo, Vulcanismo del Terciario al oeste de Somuncura y su relación con el arco magmático de la Cordillera Nordpatagónica, Argentina, IV Congr. Geol. Chile no, actas, 4: 68–88, Antofagasta, 1975.

    Google Scholar 

  • Haller, M., Crater Basalt: a back-arc postglacial event in nortwestern Patagonia, Profil, 18:33, 4 pp., 2000.

    Google Scholar 

  • Haller, M., Eruption mechanisms in the back-arc Crater Basalt Volcanic Field, Northern Patagonia, IAVCEI General Assembly, Abs. On CD. Pucón, Chile, 2004.

    Google Scholar 

  • Haller, M. and G. Massaferro, Is the Late Cenozoic intra-Plate Magmatism from Northern Patagonia Driven by Mantle “Hot Fingers”?, 19th Colloquium on Latin American Geosciences, Terra Nostra, Potsdam, 54, 2005.

    Google Scholar 

  • Haller, M., G. Massaferro, and V. Alric, Northwestern Patagonia Holocene Basalts as indicators of an incipient continental fragmentation, Geoitalia 2001. Forum Ital. Sci. Terra, 19: 580–581, Chietti, 2001.

    Google Scholar 

  • Hervé, F., A. Deman, V. Ramos, R. Pankhurst, and M. Suárez, The southern Andes. Tectonic Evolution of South America, Int. Geol. Congr.: 605–634, Rio de Janeiro, 2000.

    Google Scholar 

  • Kay, S., A. Ardolino, M. Franchi, and V. Ramos, Origen de la Meseta de Somun Cura: distribución y geoquímica de sus rocas volcánicas máficas. XII Congreso Geológico Argentino. Actas 4:236–248, Buenos Aires, 1993.

    Google Scholar 

  • Kirschvink, J. L., The least-square line and plane and analysis of palaeomagnetic data, Geophys. J. R. Astr. Soc., 62, 699–718, 1980.

    Article  Google Scholar 

  • Langerais, C. G., M. J. Dekkers, G. J. de Lange, M. Paterne, and P. J. M. van Santvoort, Magnetostratigraphic and astronomical calibration of the last 1.1 Myr from an eastern Mediterranean piston core and dating of short events in the Brunhes, Geophys. J. Int., 129, 79–94, 1997.

    Google Scholar 

  • Lapido, O. and F Pereyra, Cuaternario de la Patagonia Extrandina, in Geología Argentina, Anales 29, edited by R. Caminos, pp. 704–709, 1999.

    Google Scholar 

  • Lund, S. P., G. Acton, B. Clement, M. Hastedt, M. Okada, T. Williams, and the ODP leg 172 Scientific Party, Geomagnetic Field Excursions occurred often during the last million years, EOS Trans., AGU, 79, 178–179, 1998.

    Google Scholar 

  • Maher A. B. and R. M. Taylor, Formation of ultrafine-grained magnetite in soils, Nature, 330, 328–371, 1988.

    Google Scholar 

  • Maher A. B. and R. Thomson, Mineral magnetic records of the Chinese loess and paleosols, Geology, 19, 3–6, 1991.

    Article  Google Scholar 

  • Massaferro, G., V. Alric, and M. J. Haller, El Campo Volcánico Cuaternario del Basalto Cráter en la Patagonia Septentrional. XV Congr. Geol. Arg., actas 2, 91–96, Calafate, Argentina, 2002.

    Google Scholar 

  • Mejia, V., N. D. Opdyke, J. F. Vilas, B. S. Singer, and J. S. Stoner, Plio-Pleistocene time-averaged field in southern Patagonia recorded in lava flows, Geochem. Geophys. Geosystems, V5(3), Q03H08, doi:10.1029/2003 GC000633, 2004.

    Google Scholar 

  • Mena, M., G. H. Ré, M. Haller, S. E. Singer, and J. F. Vilas, Estudio Paleomagnético de los Basaltos Cenozoicos de Gastre (Chubut, Argentina). XVI Congreso Geológico Argentino, (CD), La Plata, Argentina, 2005.

    Google Scholar 

  • Proserpio, C. A., Descripción Geológica de la hoja 42d, Gastre, Provincia de Chubut: Serv. Geol. Nac. Bol., 159, 75 pp., 1978.

    Google Scholar 

  • Ramos, V., H. Niemeyer, J. Skarmeta, and J. Muñoz, The magmatic evolution of the Austral Patagonian Andes, Earth Sci. Rev., 18, 411–443, 1982.

    Article  Google Scholar 

  • Ravazzoli, I. A. and F. L. Sesana, Descripción Geológica de la hoja 41c, Río Chico, Provincia de Río Negro: Serv. Geol. Nac, Bol., 148, 77 pp., 1977.

    Google Scholar 

  • Singer, B. S., L. L. Brown, J. O. Rabasa, and H. Guillou, 40Ar/39Ar Chronology of Late Pliocene and Early Pleistocene Geomagnetic and Glacial events in Southern Argentina, in Timescales of the Paleomagnetic Field, Geophy. Monogr. Ser., 145, 175–190. AGU, 2004.

    Google Scholar 

  • Singer, S., M. Haller, M. Mena, G. H. Ré, and J. F. Vilas, Fábrica Magnética y Direcciones de Flujos de Lavas Pahoehoe de la Formación Cráter, Patagonia Septentrional. Actas 16° Congr. Geol. Arg., 1, 803–806, La Plata, 2005.

    Google Scholar 

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Authors and Affiliations

  1. CONICET, Argentina

    Mabel Mena, Miguel J. Haller & Juan F. Vilas

  2. INGEODAV - Dpto. Cs. Geológicas (FECyN-UBA), Argentina

    Mabel Mena, Guillermo H. Ré, Silvia E. Singer & Juan F. Vilas

  3. University of Nacional de la Patagonia San Juan Bosco, Argentina

    Miguel J. Haller

Authors
  1. Mabel Mena
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  2. Guillermo H. Ré
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  3. Miguel J. Haller
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  4. Silvia E. Singer
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  5. Juan F. Vilas
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Correspondence to Mabel Mena.

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Mena, M., Ré, G.H., Haller, M.J. et al. Paleomagnetism of the late Cenozoic basalts from northern Patagonia. Earth Planet Sp 58, 1273–1281 (2006). https://doi.org/10.1186/BF03352622

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