Studia Geophysica et Geodaetica

, Volume 61, Issue 2, pp 219–232 | Cite as

Magnetic susceptibility mapping of the Cambrian El Hongo pluton, Eastern Sierras Pampeanas, Argentina

  • Silvana GeunaEmail author
  • Leonardo Escosteguy
  • Belena Díaz Appella
  • Fernando D’Eramo
  • Lucio Pinotti


A map of bulk magnetic susceptibility was obtained on El Hongo trondhjemite, a small Cambrian pluton intruding the metamorphic basement in Eastern Sierras Pampeanas, Argentina, based on systematic magnetic susceptibility measurement at 450 sites using a SM30 susceptibility meter. Samples were collected on 58 sites and their bulk magnetic susceptibility was measured in laboratory with a Bartington MS2 system. Point-to-point comparison showed differences, that were attributed to the effect of roughness of the surveyed surfaces, and to the development of a weathered cap. However, the difference was systematic and in accordance with expected values predicted by manufacturer tables, whereby, once corrected with the appropriate factor, the obtained values with SM30 susceptibility meter were regarded as representative of fresh rocks. The resulting map was interpreted in terms of variation in abundance of magnetite, which is present in the rocks as a magmatic mineral, altered to hematite (martitized) in varying degrees. The map revealed that El Hongo trondhjemite is a weakly magnetic pluton, with a typical bulk susceptibility of about 500 × 10−6 SI, which would correspond to an abundance of magnetite below 0.2 vol%, but with conspicuous variations. Lows in the outer sector and in the vicinity of metamorphic xenoliths were interpreted as due to destruction of magnetic minerals linked to reactions between magma and host rock. A distinct concentric pattern in the western area could indicate the presence of a separate intrusion. Finally, alternate highs and lows in susceptibility follow the undulations in regional schistosity, which in turn would have controlled the emplacement of the pluton. Thus we provide a good example of the utility of magnetic susceptibility mapping in granitoid terrains, as an expeditious way for preliminary mapping that could guide further and more detailed research.


magnetic susceptibility magnetite ilmenohematite martitization handheld susceptibility meter 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Aceñolaza F.G. and Toselli A.J., 1981. Geology of Northwestern Argentina. Special Publication, Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán, Tucumán, Argentina (in Spanish).Google Scholar
  2. Bonalumi A. and Baldo E., 2002. Ordovician magmatism in the Sierras Pampeanas of Córdoba. In: Aceñolaza F.G. (Ed.), Aspects of the Ordovician System in Argentina. INSUGEO, Serie Correlación Geológica, 16, 243–256.Google Scholar
  3. Clark D.A. and Emerson D.W., 1991. Notes on rock magnetization characteristics in applied geophysical studies. Explor. Geophys., 22, 547–555.CrossRefGoogle Scholar
  4. D’Eramo F.J., 2003. Petrology and Emplacement of the El Hongo and Calmayo Plutons, and Their Relationship with the Geological Evolution of Sierra Chica de Córdoba. PhD Thesis. Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina (in Spanish).Google Scholar
  5. D’Eramo F., Pinotti L., Tubía J.M., Vegas N., Aranguren A., Tejero R. and Gómez D., 2006. Coalescence of lateral spreading magma ascending through dykes: a mechanism to form a granite canopy (El Hongo pluton, Sierras Pampeanas, Argentina). J. Geol. Soc. London, 163, 1–12.CrossRefGoogle Scholar
  6. D’Eramo F., Tubía J.M., Pinotti L., Vegas N., Coniglio J., Demartis M., Aranguren A. and Basei M., 2013. Granite emplacement by crustal boudinage: example of the Calmayo and El Hongo plutons (Córdoba, Argentina). Terra Nova, 25, 423–430.CrossRefGoogle Scholar
  7. Dalla Salda L.H., Dalziel I.W.D., Cingolani C.A. and Varela R., 1992. Did the Taconic Appalachians continue into South America? Geology, 20, 1059–1062.CrossRefGoogle Scholar
  8. de Wall H., Karl A., Nano L., Schmitt T. and Rieger M., 2000. Magnetic susceptibility measurements for the petrographic characterization of Granitoids: Comparison of field and laboratory measurements in the Saghro region of the anti-Atlas of Morocco. Z. Angew. Geol., 46, 223–230 (in German).Google Scholar
  9. de Wall H., Dietl C., Streit V., Rückert D. and Rohrmüller J., 2008. Field mapping of magnetic susceptibility as tool for petrographic characterization of granitoids - a key study in the Hauzenberg pluton, Bavarian Forest, Germany. Neues. Jahrb. Geol. Palaontol.-Abh., 248, 129–137.CrossRefGoogle Scholar
  10. Frost B.R., 1991. Magnetic petrology: factors that control the occurrence of magnetite in crustal rocks. In: Lindsley D.H. (Ed.), Oxide Minerals: Petrologic and Magnetic Significance. Reviews in Mineralogy, 25, 489–509.Google Scholar
  11. Gattacceca J., Eisenlohr P. and Rochette P., 2004. Calibration of in situ magnetic susceptibility measurements. Geophys. J. Int., 158, 42–49.CrossRefGoogle Scholar
  12. Geuna S., Escosteguy L., Díaz Appella B., D’Eramo F. and Pinotti L., 2016. Magnetic properties of xenoliths in the El Hongo trondhjemite (Cambrian), Córdoba province, Argentina. LATINMAG Lett., 6 Special Issue, D11, 1–7 (in Spanish).Google Scholar
  13. Gleizes G., Nédélec A., Bouchez J.-L., Autran A. and Rochette P., 1993. Magnetic susceptibility of the Mont-Louis Andorra ilmenite-type granite (Pyrenees): A new tool for the petrographic characterization and regional mapping of zoned granite plutons. J. Geophys. Res., 98, 4317–4331.CrossRefGoogle Scholar
  14. Hageskov B., 1984. Magnetic susceptibility used in mapping of amphibolite facies recrystallisation in basic dykes. Tectonophysics, 108, 339–351.CrossRefGoogle Scholar
  15. Heritage Geophysics Inc., 2003. Magnetic Susceptibility Meter SM-30 User’s Manual. Heritage Geophysics, Littleton, CO.Google Scholar
  16. Ishihara S., 1981. The granitoid series and mineralization. Econ. Geol., 75th Anniv. Vol., 458-484.Google Scholar
  17. Ishihara S., Anhaeusser C.R. and Robb L.J., 2002a. Granitoid-series evaluation of the Archaean Johannesburg dome granitoids, South Africa. Bull. Geol. Surv. Japan, 53, 1–9.CrossRefGoogle Scholar
  18. Ishihara S., Robb L., Anhaeusser C. and Imai A., 2002b. Granitoid series in terms of magnetic susceptibility: a case study from the Barberton Region, South Africa. Gondwana Res., 5, 581–589.CrossRefGoogle Scholar
  19. Jordanova D., Veneva L. and Hoffmann V., 2003. Magnetic susceptibility screening of anthropogenic impact on the Danube river sediments in northwestern Bulgaria - preliminary results. Stud. Geophys. Geod., 47, 403–418.CrossRefGoogle Scholar
  20. Kontny A. and Dietl C., 2002. Relationships between contact metamorphism and magnetite formation and destruction in a pluton’s aureole, White-Inyo Range, eastern California. Geol. Soc. Am. Bull., 114, 1438–1451.CrossRefGoogle Scholar
  21. Latham A.G., Harding K.L., Lapointe P., Morris W.A. and Balch S.J., 1989. On the lognormal distribution of oxides in igneous rocks, using magnetic susceptibility as a proxy for oxide mineral concentration. Geophys. J., 96, 179–184.CrossRefGoogle Scholar
  22. O’Reilly W., 1984. Rock and Mineral Magnetism. Blackie, Glasgow, U.K.CrossRefGoogle Scholar
  23. Pankhurst R.J. and Rapela C.W., 1998. The Proto-Andean margin of Gondwana: an introduction. In: Pankhurst R.J. and Rapela C.W. (Eds.), The Proto-Andean Margin of Gondwana. Geological Soc. London Spec. Publ., 142, 3–9.Google Scholar
  24. Pinotti L., D’Eramo F., Vegas N., Tubía J.M. and Coniglio J., 2004. Magnetic mineralogy of granitoids of the Sierras de Córdoba. In: Brodtkorb M.K., Koukharsky M., Quenardelle S. and Montenegro T. (Eds.), Advances in Mineralogy, Metalogeny and Petrology 2004. Proceedings of the 7th Congress of Mineralogy and Metallogeny, Río Cuarto, Córdoba, Argentina (in Spanish).Google Scholar
  25. Rapela C.W., Pankhurst R.J., Casquet C., Baldo E., Saavedra J. and Galindo C., 1998. The Pampean Orogeny of the southern Proto-Andes: Cambrian continental collision in the Sierras de Córdoba. In: Pankhurst R.J. and Rapela C.W. (Eds.), Proto-Andean margin of Gondwana. Geological Soc. London Spec. Publ., 142, 181–217.CrossRefGoogle Scholar
  26. Rochette P., 1987. Magnetic susceptibility of the rock matrix related to magnetic fabric studies. J. Struct. Geol., 9, 1015–1020.CrossRefGoogle Scholar
  27. Shaw D.M., 1961. Element distribution laws in geochemistry. Geochim. Cosmochim. Acta, 23, 116–134.CrossRefGoogle Scholar

Copyright information

© Institute of Geophysics of the ASCR, v.v.i 2017

Authors and Affiliations

  • Silvana Geuna
    • 1
    Email author
  • Leonardo Escosteguy
    • 2
  • Belena Díaz Appella
    • 1
  • Fernando D’Eramo
    • 3
  • Lucio Pinotti
    • 3
  1. 1.Departamento de Ciencias GeológicasUniversidad de Buenos Aires, IGEBA, UBA-CONICET, FCEyNCABAArgentina
  2. 2.Instituto de Geología y Recursos Minerales (IGRM)Servicio Geológico Minero ArgentinoBuenos AiresArgentina
  3. 3.Departamento de GeologíaUniversidad Nacional de Río Cuarto, CONICETRío CuartoArgentina

Personalised recommendations