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Acta Geodaetica et Geophysica Hungarica

, Volume 33, Issue 2–4, pp 167–185 | Cite as

Geological Interpretation of the Parnaíba Basin Magnetovariational Anomaly Using a 2D Sheet Current Inversion

  • B. R. Arora
  • I. Vitorello
  • A. L. Padilha
  • N. B. Trivedi
  • A. Rigoti
  • F. H. Chamalaun
Electromagnetic studies
  • 29 Downloads

Abstract

The magnetovariational response of a 2D electrical structure in the southeastern part of the Parnaíba basin, north-northeast Brazil, has been inverted in terms of laterally variable sheet current. The resulting inverted current distribution helps to visualize the overall basement configuration as a graben-horst-graben structure or alternatively indicates the presence of a resistive intrusive within a broad graben infilled with conductive sediments. Carbon bearing sediments are suggested as an alternative to hydrated sediments to account for the high conductivity of the mapped anomalies. Heating effects associated with the Cretaceous magmatic activity may be responsible in producing carbon through the pyrolysis of the hydrocarbon-saturated Paleozoic sediments or through the coalification of terrestrial plants.

Keywords

carbon-rich sediments electrical conductivity horst-graben-horst structure intracratonic basins magmatic activity magnetovariational fields pyrolysis reactions sheet current inversion 

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References

  1. Ádám A 1981: Acta Geod. Geoph. Mont. Hung., 16, 197–250.Google Scholar
  2. Ádám A 1997: In: Natural source electromagnetic induction in the Earth. B R Arora and Sriniwas eds, New Age International Limited, Publishers, New Delhi, 80–128.Google Scholar
  3. Ádám A, Pospisil L 1984: Acta Geod. Geoph. Mont. Hung., 19, 19–34.Google Scholar
  4. Ádám A, Varga G 1990: Phys. Earth Planet. Int., 60, 80–88.CrossRefGoogle Scholar
  5. Ádám A, Duma G, Gutdeutsch R, Verő J, Wallner Á 1986: J. Geophys., 59, 103–111.Google Scholar
  6. Ádám A, Nagy Z, Nemesi L, Varga G 1990a: Acta Geod. Geoph. Mont. Hung., 25, 279–291.Google Scholar
  7. Ádám A, Nagy Z, Nemesi L, Varga G 1990b: Acta Geod. Geoph. Mont. Hung., 25, 291–309.Google Scholar
  8. Ádám A, Nemesi L, Arora B R 1995: J. Geol. Soc. India, 45, 393–406.Google Scholar
  9. Ari>c K, Ádám A, Smythe D K 1997: Combined seismic and magnetotelluric imaging of the upper crust in the southern Bohemian Massif. First Break, 15, 265–271.CrossRefGoogle Scholar
  10. Arora B R 1997: In: Natural source electromagnetic induction int he Earth. B R Arora and Sriniwas eds, New Age International Limited, Publishers, New Delhi, 80–128.Google Scholar
  11. Arora B R, Ádám A 1992: Phys. Earth Planet. Int., 74, 183–190.CrossRefGoogle Scholar
  12. Arora B R, Rigoti A, Vitorello I, Padilha A L, Trivedi N B, Chamalaun F H 1997a: Magnetometer array study in north-northeast Brazil: conductive image building and functional induction modes. Pure Appl. Geophys. (communicated)Google Scholar
  13. Arora B R, Rigoti A, Vitorello I, Padilha A L, Trivedi N B, Chamalaun F H 1997b: Electrical imaging of the intracratonic Parnaíba basin, nort-northeast Brazil. J. Geomag. Geoeledr. (in press)Google Scholar
  14. Bailey R C, Edwards R N, Garland G D, Greenhouse J P 1974: J. Geomag. Geoeledr., 26, 125–146.CrossRefGoogle Scholar
  15. Banks R J 1979: Geophys. J. R. Astr. Soc., 56, 139–157.CrossRefGoogle Scholar
  16. Banks R J 1986: Geophys. J. R. Astr. Soc., 87, 595–616.CrossRefGoogle Scholar
  17. Banks R J, Beamish D 1984: Geophys. J. R. Astr. Soc., 79, 539–553.CrossRefGoogle Scholar
  18. Beamish D 1977: Geophys. J. R. Astr. Soc., 50, 311–332.CrossRefGoogle Scholar
  19. Bigarella J J 1973: In: The Ocean Basins and Margins. Vol. 1 — The South Atlantic, A E M Nairn and F G Stehli eds, Plenum Press, New York, 25–86.Google Scholar
  20. Bucha V 1980: Stud. Geophys. Geod., 24, 227–251.CrossRefGoogle Scholar
  21. Caputo M V, Lima E C 1984: In: XXXIII Congresso Brasileiro de Geologia, Rio de Janeiro, 740–752.Google Scholar
  22. >Cerv P, Pek J, Praus O 1987: Phys. Earth Planet. Int., 45, 170–178.CrossRefGoogle Scholar
  23. DNPM (Departamento Nacional de Produçāo Mineral) 1971: Mapa tectônico do Brasil 1:5000000Google Scholar
  24. Duba A, Huenges E, Nover G, Will G 1988: Geophys. J. Int., 94, 413–419.CrossRefGoogle Scholar
  25. Góes A M O, Souza J M P, Teixeira L B 1990: Petrobrás, 4, 55–64.Google Scholar
  26. Jankowski J, Pawliszyn J, Jozwiak W, Ernst T 1991: Publ. Inst. Geophys. Pol. Acad. Sci., A-19, 183–214.Google Scholar
  27. Jenkyns H 1986: In: Studies on the Mesozoic and Tertiary Geodynamics of the Periadriatic region. Eötvös University, BudapestGoogle Scholar
  28. Kirkwood S C, Hutton V R S, Sik J 1981: Geophys. J. R. Astr. Soc., 66, 481–490.CrossRefGoogle Scholar
  29. Mesner J C, Wooldridge L C 1964: Bull. Am. Assoc. Petr. Geol, 48, 1475–1512.Google Scholar
  30. Oliveira M F B, Fontes S L 1991: In: Proc. 2nd International Congress of the Brazilian Geophys. Soc., Salvador, Brazil, 1, 294–299.Google Scholar
  31. Picha B, >Cerv V, Pek J 1984: Stud. Geophys. Geod., 28, 101–112.CrossRefGoogle Scholar
  32. Schmucker U 1970: Bull. Scripps. Inst Oceanogr., 13, 1–165.Google Scholar
  33. Stanley W D 1989: Phys. Earth Planet Int, 53, 228–238.CrossRefGoogle Scholar
  34. Stanley W D, Saad A R, Ohofugi W 1985: Bull. Am. Ass. Petrol. Geol., 69, 346–360.Google Scholar
  35. Woods D V, Lilley F E M 1980: Geophys. J. R. Astr. Soc., 62, 675–689.CrossRefGoogle Scholar

Copyright information

© Akadémiai Kiadó 1998

Authors and Affiliations

  • B. R. Arora
    • 1
  • I. Vitorello
    • 1
  • A. L. Padilha
    • 1
  • N. B. Trivedi
    • 1
  • A. Rigoti
    • 2
  • F. H. Chamalaun
    • 3
  1. 1.Instituto Nacional de Pesquisas Espaciais - INPESáo José dos CamposBrazil
  2. 2.Departamento de GeologiaUniversidade Federal do ParanáCuritibaBrazil
  3. 3.School of Earth SciencesFlinders University of South AustraliaAdelaideAustralia

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