1887

Abstract

Summary

More than hundreds of kimberlites occur along a 3000-km-long, northwest-southeast trending, major crustal fracture zone of Brazil. This tectonic feature passes over Serra da Canastra Diamondiferous Province, Minas Gerais, Brazil. Kimberlites are main source rocks forming the diamondiferous deposits of Serra da Canastra Province. Kimberlites exhibit low-resistivity anomalies which can easily be mapped by Audiomagnetotellurics (AMT). One-hundred AMT stations were obtained over the Canastra-8 kimberlite pipe, which belongs to a well known Serra da Canastra Diamondiferous Province. All sites were processed to produce the impedance transfer function for frequency ranging between 100 kHz - 10 Hz. Phase tensor analysis parameters, phase skews, maximum and minimum phases overviews the three-dimensionality and low-resistivity of kimberlite pipes and high-resistivity of surrounding host rocks. Three-dimensional robust conductivity model was constructed for C-8 kimberlite pipe after various a priori uniform half-space model tests. Kimberlite pipes mapped by AMT 3-D model, branch out in two pipes below 300 m and seems to be a single pipe for depths between 300 – 700 m. 3D resistivity model shows that the crater phase of kimberlites may branch out in several thin pipes in the region. However, deep diatreme phase of kimberlites thickens out with depth, unlike previous models.

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/content/papers/10.3997/2214-4609.201900975
2019-06-03
2024-03-29
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References

  1. Andrade, K.W.
    , 2012, Chemistry of Kimberlite Heavy Minerals for Canastra Range Diamond Province (Minas Gerais, Brazil): Importance in Fertile Intrusions Exploration, UFMG, Master Thesis.
    [Google Scholar]
  2. Bibby, H.M., Caldwell, T.G., and Brown, C.
    , 2005, Determinable and non-determinable parameters of galvanic distortion in magnetotellurics. Geophysical Journal International, 163(3), 915–930.
    [Google Scholar]
  3. Chaves, M. L. D. S. C., Andrade, K.W., Benitez, L., et al.
    , 2008, Província diamantífera da Serra da Canastra e o kimberlito Canastra-1: primeira fonte primária de diamantes economicamente viável do país. Geociências, 27(3), 299–317.
    [Google Scholar]
  4. Egbert, G.D.
    , 1997, Robust multiple-station magnetotelluric data processing. Geophysical Journal International, 130(2), 475–496.
    [Google Scholar]
  5. Heineck, C.A., Leite, C.A.S., Silva, MA., Vieira, V.S.
    , 2003Mapa geológico do Estado de Minas Gerais, Escala 1:1.000.000. Belo Horizonte: Convênio COMIG/CPRM, 1 folha.
    [Google Scholar]
  6. Kelbert, A., Meqbel, N., Egbert, G, D., and Tandon, K.
    , 2014, ModEM: A modular system for inversion of electromagnetic geophysical data. Computational Geosciences, 66, 40–53.
    [Google Scholar]
  7. La Terra, E.F., and Menezes, P.T.L.
    , 2012, Audiomagnetotelluric 3D imaging of the Regis kimberlite pipe, Minas Gerais, Brazil. Journal of Applied Geophysics77, 30–38.
    [Google Scholar]
  8. Neto, I.C., Nannini, F., Silveira, F.V., Cunha, L.M.
    , 2017. Areas kimberliticas e diamantiferas do estado de Minas Gerais, in: Programa Geologia do Brasil. CPRM. number 10 in Projeto Diamantes do Brasil.
    [Google Scholar]
  9. Reed, L.E., and Witherly, K.E.
    , 2007, 50 Years of Kimberlite Geophysics, A Review. In "Proceedings of Exploration 07: Fifth Decennial International Conference on Mineral Exploration" edited by B. Milkereit, 679–689.
    [Google Scholar]
  10. Schobbenhaus, C, Campos, DA., Derze, G.R., and Asmus, H.E.
    , 1984. Geologia do Brasil. DNPM.
    [Google Scholar]
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