Skip to main content


We’d like to understand how you use our websites in order to improve them. Register your interest.

Gilbert-Gauss geomagnetic reversal recorded in Pliocene volcanic sequences from Georgia (Lesser Caucasus): revisited


We carried out a detailed paleomagnetic, rock-magnetic, and Thellier paleointensity study of an ~3.6 My Pliocene lava flow succession in southern Georgia. An earlier study (Camps et al., 1996) revealed that several consecutive lava flows record an intermediate polarity direction at the base of the section followed by a thick reverse polarity zone. The transitional field was interpreted as an excursion within chron 2Ar or an upper Cochiti-Gilbert reversal. New paleomagnetic data reported here have been obtained from nearby lava successions. In total, about 170 standard paleomagnetic cores belonging to 22 lava flows were collected during the 2005 sample collection campaign. Rock-magnetic experiments showed that the remanence is carried by Ti-poor titanomagnetite in most of the samples. The fraction of grains with multidomain magnetic structure does not seem to be important. Characteristic remanent magnetization was successfully determined on all samples. The direct correlation with the original (Thoki) sequence, previous preliminary measurements of natural remanent magnetization (Sologashvili, 1986), and field observations allowed us to establish a new magnetic stratigraphy. The lower part of section is characterized by intermediate magnetic polarity followed by thick reversely magnetized lavas. The upper sequence, represented by 18 consecutive flows yielded normal magnetic polarity. The mean paleointensity of the intermediate field is drastically reduced with respect to the post-transitional field strength. Based on all available radiometric ages and new paleomagnetic data, it may be speculated that Gilbert-Gauss (R-N) reversal was recorded at the upper part of sequence. Lower intermediate polarity flows possibly represent a form of precursor of this reversal that is similar to the Matuyama-Brunhes geomagnetic transition.


  1. Bogue, S. W. and H. A. Paul, Distinctive field behaviour following geomagnetic reversals, Geophys. Res. Lett., 20, 2399–2402, 1993.

  2. Camps, P., G. Ruffet, V. P. Scherbakov, V. V. Scherbakova, M. Prévot, A. Moussine-Pouchkin, L. Sholpo, A. Goguitchaichvili, and B. Asanidze, Paleomagnetic and geocronological study of a geomagnetic field reversal or excursion recorded in Pliocene volcanic rocks from Georgia (lesser Caucasus), Phys. Earth Planet. Inter., 96, 41–59, 1996.

  3. Carcaillet, J. T., D. Bourles, and N. Thouveny, Geomagnetic dipole moment and 10Be production rate intercalibration from authigenic 10Be/9 Be for the last 1.3 Ma, Geochem. Geophys., Geosyst., 5, doi 1029/2003GC000641, 2004.

  4. Coe, R., Paleointensity of the Earth’s magnetic field determined from Tertiary and Quaternary rocks, J. Geophys. Res., 83, 1740–1756, 1967.

  5. Coe, R. S., S. Grommé, and E. A. Mankinen, Geomagnetic paleointensities from radiocarbon-dated lava flows on Hawaii and the question of the Pacific nondipole low, J. Geophys. Res., 83, 1740–1756, 1978.

  6. Cox, A., Lengths of geomagnetic polarity intervals, J. Geophys. Res., 73, 3247–3260, 1968.

  7. Day, R., M. Fuller, and V. A. Schmidt, Hysteresis properties of titanomag-netites: Grain-size and compositional dependence, Phys. Earth Planet. Inter., 13, 260–267, 1977.

  8. Dunlop, D. J., Theory and application of the Day plot (Mrs/Ms versus Hcr/Hc), Theoretical curves and tests using titanomagnetite data, J. Geophys. Res., 107, doi:10.1029/2001JB000486, 2002.

  9. Dunlop, D. and Ö. Özdemir, Rock-Magnetism, fundamentals and frontiers, 573 pp., Cambridge University Press, 1997.

  10. Goguitchaichvili, A., D. Sologachvili, M. Prévot, M. Calvo, E. S. Pavlenichvili, G. Maissuradze, and E. Schnepp, Paleomagnetic and rock-magnetic study of a Pliocene volcanic section in south Georgia (Caucasus), Geol. Mijnbouw, 76, 135–143, 1997.

  11. Goguitchaichvili, A., M. Prévot, J. M. Dautria, and M. Bacia, Thermo-detrital and crystalline magnetizations in an Icelandic hyaloclastite, J. Geophys. Res., 104, 29219–29239, 1999a.

  12. Goguitchaichvili, A., M. Prévot, N. Roberts, and J. Thompson, An attempt to determine the absolute geomagnetic field intensity in Southwestern Iceland during the Gauss-Matyama reversal, Phys. Earth Planet. Inter., 115, 53–66, 1999b.

  13. Goguitchaichvili, A., M. Prévot, and P. Camps, No evidence for strong fields during the R3-N3 Icelandic geomagnetic reversals, Earth Planet. Sci. Lett., 167, 15–34, 1999c.

  14. Goguitchaichvili, A., J. Morales, and J. Urrutia-Fucugauchi, On the use of thermomagnetic curves in paleomagnetism, C. R. Acad. Sci., Earth Planet. Sci., 333, 699–704, 2001a.

  15. Goguitchaichvili, A., P. Camps, and J. Urrutia-Fucugauchi, On the features of the geodynamo following reversals or excursions, Phys. Earth Planet. Inter., 124, 81–93, 2001b.

  16. Gratton, M. and J. Shaw, Absolute palaeointensity variation during a precursor to the Matuyama-Brunhes transition recorded in Chilean lavas, Earth Planet. Sci. Lett., 162(1–2), 61–72, 2007.

  17. Gubbins, D., The distinction between geomagnetic excursions and reversals, Geophys. J. Int., 137, F1–F3, 1999.

  18. Hartl, P. and L. Tauxe, A precursor to the Matuyama/Brunhes transition—field instability as recorded in pelagic sediments, Earth Planet. Sci. Lett., 138, 121–135, 1996.

  19. Herrero-Bervera, E. and J. P. Valet, Absolute paleointensity and reversal records from the Wainanae sequence (Oahu, Hawaii, USA), Earth Planet. Sci. Lett., doi:10.1016/j.epsl.2005, 2005.

  20. Kent, D. V. and D. A. Schneider, Correlation of paleointensity variation records in the Brunhes/Matuyama polarity transition interval, Earth Planet. Sci. Lett., 129, 135–142, 1995.

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

  22. Knudsen, M. F., N. Abrahamsen, and P. Riisager, Paleomagnetic evidence from Cape Verde Islands basalts for fully reversed excursions in the Brunhes Chron, Earth Planet. Sci. Lett., 206, 199–214, 2003.

  23. Kosterov, A., M. Perrin, J. M. Glen, and R. S. Coe, Paleointensity of the Earth’s magnetic field in early Cretaceous time: The Paraná Basalt, Brazil, J. Geophys. Res., 103, 9739–9753, 1998.

  24. Laj, C., A. Mazaud, R. Weeks, and E. Herrero-Bervera, Geomagnetic reversal paths, Nature, 351, 347–350, 1991.

  25. Levi, S., The effect of magnetite particle size in paleointensity determination of the geomagnetic field, Phys. Earth Planet. Inter., 13, 245–258, 1977.

  26. Maissuradze, G., Antropogene of Anti-Caucasus, Paleogr. Paleoclim. Paleoecol., 72, 53–61, 1989.

  27. Mankinen, E. A., M. Prévot, C. S. Grommé, and R. Coe, The Steens Mountain (Oregon) geomagnetic polarity transition 1, Directional history, duration of episodes and rock-magnetism, J. Geophys. Res., 90, 10393–10416, 1985.

  28. Merrill, R. T. and P. L. McFadden, Geomagnetic field stabuility: Reversal events and excursions, Earth Planet. Sci. Lett., 121, 57–69, 1994.

  29. Milanovski, E. E., Neotectonics of the Caucasus, 278 pp., Nedra, 1978 (in Russian).

  30. Mochizuki, N., H. Tsunakawa, H. Shibuya, J. Cassidy, and I. E. M. Smith, Palaeointensities of the Auckland geomagnetic excursions by the LTD-DHT Shaw method, Phys. Earth Planet. Inter., 154, 168–179, 2006.

  31. Mochizuki, N., H. Tsunakawa, H. Shibuya, T. Tagami, A. Ozawa and I. E. M. Smith, Further K-Ar dating and paleomagnetic study of the Auckland geomagnetic excursions, Earth Planets Space, 59, 755–761, 2007.

  32. Nagata, T., R. M. Fisher, and K. Momose, Secular variation of the geomagnetic total force during the last 5000 years, J. Geophys. Res., 68, 5277–5281, 1963.

  33. Özdemir, Ö., Inversion of titanomaghemites, Phys. Earth Planet. Inter., 65, 125–136, 1987.

  34. Petronille, M., A. Goguitchaichvili, B. Henry, L. Alva-Valdivia, J. Rosas-Elguera, M. Rodríguez Ceja, and M. Calvo-Rathert, Paleomagnetism of Ar-Ar dated lava flows from the Ceboruco-San Pedro volcanic field (western Mexico): Evidence for the Matuyama-Brunhes transition precursor and a fully reversed geomagnetic event in the Brunhes chron, J. Geophys. Res., 110, B08101, doi:10.1029/2004jb003321, 2005.

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

  36. Prévot, M., R. S. Mainkinen, R. S. Coe, and S. Grommé, The Steens Mountain (Oregon) geomagnetic polarity transition 2. Field intensity variations and discussion of reversal models, J. Geophys. Res., 90, 10417–10448, 1985.

  37. Quidelleur, X., J. Carlut, P. Y. Gillot, and V. Soler, Evolution of the geomagnetic field prior to the Matuyama-Brunhes transition: radiometric dating of a 820 ka excursion at La Palma, Geophys. J. Int., 151, F6–F10, 2002.

  38. Riisager, P. and N. Abrahamsen, Palaeointensity of West Greenland Palaeocene basalts: asymmetric intensity around the C27n-C26r transition, Phys. Earth Planet. Inter., 118, 53–64, 2000.

  39. Riisager, P., J. Riisager, N. Abrahamsen, and R. Waagstein, Thellier pa-leointensity experiments on Faroes Flood Basalts: Technical aspects and Geomagnetic Implications, Phys. Earth Planet. Inter., 131, 91–100, 2002.

  40. Singer, B. S., M. K. Relle, K. A. Hoffman, A. Battle, C. Laj, H. Guillou, and J. Carracedo, Ar/Ar ages from transitionally magnetized lavas on La Palma, Canary Island, and the geomagnetic instability timescale, J. Geophys. Res., 107(B11), 10.1029/2001JB001613, 2002.

  41. Sologashvili, J., Paleomagnetism of Neogene volcanic units of Georgia, Phd Thesis, Tbilisi State University, 168 pp., 1986.

  42. Tanaka, H., M. Kono, and S. Kaneko, Paleosecular variation of direction and intensity from two Pliocene-Pleistocene lava sections in Southwestern Iceland, J. Geomag. Geoelectr., 47, 89–102, 1995.

  43. Tauxe, L., Sedimentary records of relative paleointensity: Theory and practice, Rev. Geophys., 31, 319–354, 1993.

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

  45. Thellier, E. and O. Thellier, Recherches géomagnetiques sur les coulees volcaniques d’Auvergne, Ann. Geophys., 1, 37–52, 1944.

  46. Thellier, E. and O. Thellier, Sur l’intensité du champ magnétique terrestre dans le passé historique et géologique, Ann. Géophys., 15, 285–376, 1959.

  47. Valet, J. P. and E. Herrero-Bervera, Paleointensity experiments using alternating field demagnetization, Earth Planet. Sci. Lett., 177, 43–58, 2000.

  48. Valet, J. P. and E. Herrero-Bervera, Some characteristics of geomagnetic reversals inferred from detailed volcanic records, C. R. Geosci., 335, 79–90, 2003.

Download references

Author information



Corresponding author

Correspondence to Avto Goguitchaichvili.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Goguitchaichvili, A., Cervantes, M.A., Rathert, M.C. et al. Gilbert-Gauss geomagnetic reversal recorded in Pliocene volcanic sequences from Georgia (Lesser Caucasus): revisited. Earth Planet Sp 61, 71–81 (2009).

Download citation

Key words

  • Paleomagnetism
  • reversals
  • excursions
  • paleointensity
  • Caucasus