Acta Geodaetica et Geophysica Hungarica

, Volume 44, Issue 2, pp 157–166 | Cite as

Preliminary magnetotelluric study of Ambato and Valle Fértil lineaments in Bermejo Basin and Sierra de Valle Fértil, San Juan, Argentina



In the western region of Argentina, 30° S Lat., near the Andean Range, two Precambrian large faults or lineaments are present: Ambato (AL) (NE-SW) and Valle Fértil (VFF)(∼NS). They are deep-seated faults in the crust, with extend develop in time, crossing each other in the region where Bermejo Basin and Valle Fértil Range (Sierra de Valle Fértil, SVF) are present. The study of these lineaments is important to better know the tectonic evolution of this region. Three deep magnetotelluric soundings were carried out in this zone using induction coils and a flux-gate magnetic variometer. Principal results show a thickness up to 7000 m and saline character for the Bermejo Basin, with resistivities range frm 3 Ωm to 13 Ωm, and an integrated conductivity of 1600 Siemens. High conductivity is also suggested for the AL from the top of basement to higher depths. Westward of VFF, beneath the Bermejo Basin, a conductive lower crust is suggested with a longitudinal conductance at least of 1600 Siemens and seated at 43 km depth; but this layer does not seem to be present eastward of the fault. A possible phase transition zone at 300 km depth is also suggested. From these conductive layers, a heat flow estimate of 36–40 mW/m2 is made for the region, using empirical formulas. Graphite is suspected to be the cause of lower crust conductivity. If correct, it would be suggesting a strong ancient tectonic activity, with probable dipping and lifting of significant amplitude in the region.


Bermejo Basin heat flow magnetotelluric Precambrian deep faults 


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  1. Ádám A ed. 1976: Geoelectric and Geothermal Studies (East-Central Europe, Soviet-Asia), KAPG Geophysical Monograph. Budapest, Akadémiai KiadóGoogle Scholar
  2. Ádám A 1978: Phys. Earth Planet. Int., 17, 21–28.CrossRefGoogle Scholar
  3. Ádám A 1980: J. Geomagn. Geoelectr., 32, 115–124.Google Scholar
  4. Ádám A 2005: Acta Geod. Geoph. Hung., 40, 391–411.CrossRefGoogle Scholar
  5. Baldis B 1989: Correl. Geol., 5, 67–81.Google Scholar
  6. Baldis B A 1990: Relaciones de estructuras de cizalla pampeanas con la placa sudamericana y el continente Gondwana. 11° Congreso Geológico Argentino, San Juan, Actas II, 301–305.Google Scholar
  7. Berdichevsky M N, Vanyan L L, Dmitriev V I 1989: Phys. Earth Planet. Int., 53, 194–206.CrossRefGoogle Scholar
  8. Berdichevsky M N, Dmitriev V I, Pozdnjakova E E 1998: Geophys. J. Int., 133, 585–606.CrossRefGoogle Scholar
  9. Caminos R 1979: Sierras Pampeanas Noroccidentales, Salta, Tucumán, Catamarca, La Rioja y San Juan. 2do. Simposio Geología Regional Argentina, vol. I, Academia Nacional de Ciencias, Córdoba, Argentina, 225–291.Google Scholar
  10. Feldman I S 1976: In: Geoelectric and Geothermal Studies, KAPG Geophysical Monograph, A Ádám ed., Akadémiai Kiado, Budapest, 719–730.Google Scholar
  11. Fromm R, Zandt G, Beck S L 2004: Geophys. Res. Lett., 31, L06625, doi: 10.1029/2003.CrossRefGoogle Scholar
  12. Gilbert H, Beck S, Zandt G 2006: Geophys. J. Int., 165, 383–398.CrossRefGoogle Scholar
  13. Jordan T E, Schlunegger F, Cardozo N 2001: J. S. Am. Earth Sci., 14, 775–798.CrossRefGoogle Scholar
  14. Pollack H N, Hurter S J, Johnson J R 1993: Rev. Geophysics, 31, 267–280.CrossRefGoogle Scholar
  15. Rokityansky I I 1982: Geoelectromagnetic Investigation of the Earth’s Crust and Mantle. Springer-Verlag, BerlinCrossRefGoogle Scholar
  16. Ruiz F, Introcaso A 2001: Acta Geod. Geoph. Hung., 36, 1–16.CrossRefGoogle Scholar
  17. SEGEMAR 1997: Mapa Geológico de la República Argentina. Servicio Geológico Minero Argentino. Buenos Aires, ArgentinaGoogle Scholar
  18. Vozoff K 1972: Geophysics, 37, 98–141.CrossRefGoogle Scholar
  19. Zapata T R 1998: J. S. Am. Earth Sci., 11, 131–151.CrossRefGoogle Scholar
  20. Zhamaletdinov A, Feldman I 2006: The Nature of the Earth Crust and Upper Mantle Conductivity. Extended abstract, 18th Workshop, IAGA WG 1.2 on Electromagnetic induction in the Earth. El Vendrell, SpainGoogle Scholar
  21. Zhamaletdinov A A, Semenov A S 1983: In: The development of the deep geoelectric model of the Baltic Shield. Part 2. S E Hjelt ed., Department of Geophysics, Report No. 8, University of Oulu, Finland, 17–36.Google Scholar

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© Akadémiai Kiadó 2009

Authors and Affiliations

  1. 1.Unidad de Geofísica, Instituto Argentino de Nivología, Glaciología y Ciencias AmbientalesIANIGLA, CONICETMendozaArgentina

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