Skip to main content

Rock-magnetism and ore microscopy of the magnetite-apatite ore deposit from Cerro de Mercado, Mexico

Abstract

Rock-magnetic and microscopic studies of the iron ores and associated igneous rocks in the Cerro de Mercado, Mexico, were carried out to determine the magnetic mineralogy and origin of natural remanent magnetization (NRM), related to the thermo-chemical processes due to hydrothermalism. Chemical remanent magnetization (CRM) seems to be present in most of investigated ore and wall rock samples, replacing completely or partially an original thermoremanent magnetization (TRM). Magnetite (or Ti-poor titanomagnetite) and hematite are commonly found in the ores. Although hematite may carry a stable CRM, no secondary components are detected above 580°, which probably attests that oxidation occurred soon enough after the extrusion and cooling of the ore-bearing magma. NRM polarities for most of the studied units are reverse. There is some scatter in the cleaned remanence directions of the ores, which may result from physical movement of the ores during faulting or mining, or from perturbation of the ambient field during remanence acquisition by inhomogeneous internal fields within these strongly magnetic ore deposits. The microscopy study under reflected light shows that the magnetic carriers are mainly titanomagnetite, with significant amounts of ilmenite-hematite minerals, and goethite-limonite resulting from alteration processes. Magmatic titanomagnetites, which are found in igneous rocks, show trellis, sandwich, and composite textures, which are compatible with high temperature (deuteric) oxy-exsolution processes. Hydrothermal alteration in ore deposits is mainly indicated by martitization in oxide minerals. Grain sizes range from a few microns to >100 μm, and possible magnetic state from single to multidomain, in agreement with hysteresis measurements. Thermal spectra, continuous susceptibility measurements, and IRM (isothermal remanent magnetization) acquisition suggest a predominance of spinels as magnetic carriers, most probably titanomagnetites with low-Ti content. For quantitative modeling of the aeromagnetic anomalies, we used data on bulk susceptibility and natural remanent intensity for quantifying the relative contributions of induced and remanent magnetization components and allow a better control of the geometry of source bodies. The position and geometry of this magnetic source are shown as an ENE-striking tabular body, steeply inclined (75°) to the south.

References

  • Alva-Valdivia, L. and J. Urrutia-Fucugauchi, Rock magnetic surveys in the iron ore deposit of El Encino, Mexico, J. South Am. Earth Sci., 8, 209–220, 1995.

    Article  Google Scholar 

  • Alva-Valdivia, L. and J. Urrutia-Fucugauchi, Rock magnetic properties and ore microscopy of the iron ore deposit of Las truchas, Michoacan, Mexico, J. Applied Geophys., 38, 277–299, 1998.

    Article  Google Scholar 

  • Alva-Valdivia, L., J. Urrutia-Fucugauchi, H. Böhnel, and D. Moran-Zenteno, Aeromagnetic anomalies and paleomagnetism in Jalisco and Michoacan, southern Mexico continental margin, and their implications for iron-ore deposits exploration, Tectonophys., 192, 169–190, 1991.

    Article  Google Scholar 

  • Alva-Valdivia, L., D. J. Dunlop, and J. Urrutia-Fucugauchi, Rock magnetic properties of iron ores and host rocks from the Peña Colorada mining district, western Mexico, J. Applied Geophys., 36, 105–122, 1996.

    Article  Google Scholar 

  • Bookstrom, A. A., The magnetite deposits of El Romeral, Chile, Econ. Geol., 72, 1101–1130, 1977.

    Article  Google Scholar 

  • Clark, D. A. and P. W. Schmidt, Palaeomagnetism and magnetic anisotropy of Proterozoic banded-iron formations and iron ores of the Hamersley basin, Western Australia, Explor. Geophys., 24, 223–226, 1993.

    Article  Google Scholar 

  • Consejo de Recursos Minerales, Monografía Geologico-Minera del Estado de Durango, 1993.

  • Day, R., M. Fuller, and V. A. Schmidt, Hysteresis properties of titanomagnetites: grain size and compositional dependence, Phys. Earth Planet. Int., 13, 260–267, 1977.

    Article  Google Scholar 

  • Dunlop, D., The rock-magnetism of fine particles, Phys. Earth Planet. Int., 26, 1–26, 1981.

    Article  Google Scholar 

  • Dunlop, D. and O. Ozdemir, Rock-Magnetism, fundamentals and frontiers, Cambrige University Press, 573 pp., 1997.

  • Ehrlich, M., S. Sun, L. H. Scharon, and H. C. Soffel, Magnetic and paleomagnetic investigations of the Precambrian Iron Mountain deposits, Southeast Missouri, Trans. Inst. Min. Metall., Sec. B, 78, B114–B122, 1969.

    Google Scholar 

  • Frietsch, R., On the magmatic origin of iron ores of the Kirunatype, Econ. Geol., 73, 478–485, 1978.

    Article  Google Scholar 

  • Goguitchaichvili, A., Inversion géomagnétique en Georgie du Sud et étude d’un exemple d’auto-inversion (Pinatubo), MSc Thesis, Univ. Montpellier, 68 pp., 1995.

  • Goguitchaichvili, A., D. Z. Sologashvili, M. Prévot, M. Calvo, E. S. Pavlenishvili, G. M. Maissuradze, and E. Schnepp, Paleomagnetic and rockmagnetic study of a Pliocene volcanic section in south Georgia (Caucasus), Geologie en Mijnbouw, 76, 135–143, 1997.

    Article  Google Scholar 

  • Goguitchaichvili, A., A. Chauvin, P. Roperch, M. Prévot, M. Vergara, and H. Moreno, Paleomagnetism of the Miocene Farellones Formation in Chile, Geophys. J. Int., 140, 357–374, 2000.

    Article  Google Scholar 

  • Grant, F. S., Aeromagnetics, Geology and Ore Environments, I. Magnetite in Igneous, Sedimentary and Metamorphic Rocks: an overview: Geoexploration, vol. 23, pp. 303–333, 1985.

    Google Scholar 

  • Grommé, C. S., T. L. Wright, and D. L. Peck, Magnetic properties and ixidation of iron-titanium oxide minerals in Alae makaupuki lava lakes, Hawaii, J. Geophys. Res., 74, 5277–5293, 1969.

    Article  Google Scholar 

  • Haggerty, S. E., Oxidation of opaque mineral oxides in basalts, in Oxide Minerals (Short Course Notes), edited by D. Rumble, Mineral. Soc. Am., 3, 1–100, 1976.

    Google Scholar 

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

    Article  Google Scholar 

  • Kobayashi, K., Chemical remanent magnetization of ferromagnetic minerals and its application to rock magnetism, J. Geomag. Geoelectr., 10, 99–117, 1959.

    Article  Google Scholar 

  • Labarthe, G., J. L. Carreon, and A. Aguillon, Cerro de Mercado, in Minas Mexicanas Tomo 5, edited by J. Ordoñez, pp. 69-91, C. AIME-SEG, 1990.

  • Leslie, S. L., Chemical remanent magnetization in iron ores and wall rocks of Cerro de Mercado, Durango, Mexico, Unpublished MSc Thesis, Univ. of Minnesota, 1975.

  • Lyons, J. I., Volcanogenic iron ore of Cerro de Mercado and its setting within the Chupaderos Caldera, Durango, Mexico, M.A. Thesis, Austin, Univ. Texas, 119 pp., 1975.

    Google Scholar 

  • Lyons, J. I., Volcanogenic iron oxide deposits, Cerro de Mercado and vicinity, Durango, Mexico, Econ. Geol., 83, 1886–1906, 1988.

    Article  Google Scholar 

  • McDowell, F. W. and R. P. Keizer, Timing of mid-Tertiary volcanism in the Sierra Madre Occidental between Durango City and Mazatlan, Mexico, Geol. Soc. Am. Bull., 88, 1479–1486, 1977.

    Article  Google Scholar 

  • Nishitani, T. and M. Kono, Effects of low-temperature oxidation on the remanence properties of titanomagnetites, J. Geomag. Geoelectr., 41, 19–38, 1989.

    Article  Google Scholar 

  • Nystrom, J. O. and F. Henriquez, Magmatic features of iron ores of the Kiruna type in Chile and Sweden: ore textures and magnetite geochemistry, Econ. Geol., 89, 820–839, 1994.

    Article  Google Scholar 

  • Ozdemir, O., Inversion of titanomaghemites, Phys. Earth Planet. Int., 65, 125–136, 1987.

    Article  Google Scholar 

  • Ozdemir, O. and S. K. Banerjee, High temperature stability of maghemite, Geophys. Res. Lett., 90, 11513–11523, 1984.

    Article  Google Scholar 

  • Prévot, M., E. A. Mainkinen, S. Grommé, and A. Lecaille, High paleointensity of the geomagnetic field from thermomagnetic studies on rift valley pillow basalts from the middle Atlantic ridge, J. Geophys. Res., 88, 2316–2326, 1983.

    Article  Google Scholar 

  • Readman, P. W. and W. O’Reilly, The synthesis and inversion of nonstoichiometric titanomagnetites, Phys. Earth Planet. Int., 4, 121–128, 1970.

    Article  Google Scholar 

  • Shcherbakova, V. V., V. P. Shcherbakova, P. W. Schmidt, and M. Prévot, On the effect of low temperature demagnetizations of TRMs and pTRMs, Geophys. J. Int., 127, 379–386, 1996.

    Article  Google Scholar 

  • Storevedt, K. M., On remagnetization problems in paleomagnetism: further considerations, Earth Planet. Sci. Lett., 9, 409–415, 1970.

    Google Scholar 

  • Swanson, E. R., Petrology and volcanic stratigraphy of the Durango area, Durango, Mexico, Unpublished M. A. Thesis, Univ. Texas, Austin, 1974.

    Google Scholar 

  • Symons, D. T. A., A. W. Quick, and M. Stupavsky, Magnetic and paleomagnetic characteristics of the Archean iron formation and host rocks at the Adams mine, Ontario, Ont. Geol. Surv. Misc. Pap., 98, 293–307, 1981.

    Google Scholar 

  • Talwani, M., Computation with the help of a digital computer of magnetic anomalies caused by bodies of arbitrary shape, Geophys., 20, 797–817, 1965.

    Article  Google Scholar 

  • Tauxe, L., T. A. T. Mullender, and T. Pick, Pot-bellies, wasp-waists and superparamagnetism in magnetic hysteresis, J. Geophys. Res., 95, 12337–12350, 1996.

    Article  Google Scholar 

  • Travisany, V., F. Henriquez, and J. O. Nystrom, Magnetite lava flows in the Pleito-Melon district of the Chilean iron belt, Econ. Geol., 99, 438–444, 1995.

    Article  Google Scholar 

  • Zijderveld, J. D. A., A.C. demagnetization of rocks: analysis of results, in Methods in Paleomagnetism, edited by D. W. Collinson, K. M. Creer, and S. K. Runcorn, Elsevier, Amsterdam.

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to L. M. Alva-Valdivia.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Alva-Valdivia, L.M., Goguitchaichvili, A., Urrutia-Fucugauchi, J. et al. Rock-magnetism and ore microscopy of the magnetite-apatite ore deposit from Cerro de Mercado, Mexico. Earth Planet Sp 53, 181–192 (2001). https://doi.org/10.1186/BF03352375

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1186/BF03352375

Keywords

  • Magnetite
  • Hematite
  • Remanent Magnetization
  • Magnetic Anomaly
  • Natural Remanent Magnetization