Izvestiya, Physics of the Solid Earth

, Volume 51, Issue 4, pp 469–479 | Cite as

Deep structure and isostasy of the central Scotia Sea

Article

Abstract

About 30 Ma ago in the Early Oligocene, the Drake Passage started to open and the Scotia lithospheric plate started to form. Although extensively studied during the past decade, the tectonic structure and evolution of the plate are still largely unclear. According to present-day notions, three large blocks—western, central, and eastern—are distinguished within the plate by the morphological features of undersea topography and anomalous geophysical fields in different reductions. From the standpoint of the origin and evolution, the central block is most interesting. In this work, we have studied the peculiar features of the deep structure and mechanism of isostatic equilibration for the central part of this plate using density modeling and cross-spectral analyzing. The density model has been constructed along the free-air gravity profile that intersects the central part of the Scotia Sea from the southeast to the northwest. The model estimates of crustal density are slightly lower than the average density of the oceanic crust and vary within 2.65 to 2.75 g/cm3. The transfer functions between the bathymetry and free-air gravity anomalies (gravitational admittance) have been calculated. By comparing the predicted and empirical transfer functions, we determined the mechanism of isostatic compensation and estimated the depths of the compensating boundaries. Together with the results of morphological analysis on undersea topography and geophysical fields (Teterin et al., 2015), these estimates suggest that the central Scotia Sea probably followed a different evolution scenario than the commonly accepted spreading model. This part of the Scotia Sea is probably a large fragment of the continental bridge that connected the South America with Antarctic and sank due to the heating and extension of the continental lithosphere.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Artem’ev, M.E. and Kaban, M.K., Cross-spectral analysis of gravity field and external loading in the isostatic compensation model: the case study of the Caucasus, Izv. Akad. Nauk SSSR, Fiz. Zemli, 1986, no. 2, pp. 54–65.Google Scholar
  2. Artem’ev, M.E., State of the art of the isostasy problems, in Stroenie i evolyutsiya tektonosfery (The structure and Evolution of the Tectonosphere), Moscow: IFZ AN SSSR, 1987, pp. 216–249.Google Scholar
  3. Barker, P., Dalziel, I., and Storey, B., Tectonic development of the Scotia arc region, in The Geology of Antarctica, Oxford: Clarendon, 1991, pp. 215–248.Google Scholar
  4. Barker, P., Scotia Sea regional tectonic evolution: implications for mantle flow and palaeocirculation, Earth Sci. Rev., 2001, vol. 55, pp. 1–39.CrossRefGoogle Scholar
  5. Bulychev, A.A, Gilod, D.A., Zaitsev, A.N., Teterin, D.E., and Kalisheva, M.V., The tectonosphere structure of the Scotia Sea from gravity data, Vestn. Mosk. Gos. Univ., Series 4: Geology, 2002, vol. 4, pp. 69–80.Google Scholar
  6. Bulychev, A.A. and Zaitsev, A.N., The Program for Solving the Inverse Problem of Gravity Field Fitting in 2D Case. RF State PC Program Certificate 2008611949 of April 18, 2008.Google Scholar
  7. Carlson, R.L. and Raskin, G.S., Density of the Ocean Crust, Nature, 1984, vol. 311, pp. 555–558.CrossRefGoogle Scholar
  8. Dubinin, E.P., Transformnye razlomy okeanicheskoi litosfery (Transform Faults in the Oceanic Lithosphere), Moscow: MGU, 1987.Google Scholar
  9. Dubinin, E.P., Grokhol’skii, A.L., Kokhan, A.V., Kurbatova, E.S., Sushchevskaya, N.M., and Teterin, D.E., Riftogenic basins of the Scotia Sea, in Zhizn’ Zemli (Life of the Earth), Moscow: MSU, 2014, vols. 35/36. pp. 102–123.Google Scholar
  10. Eagles, G., Livermore, R., and Morris, P., Small basins in the Scotia Sea: the Eocene Drake Passage gateway, Earth Planet. Sci. Lett., 2006, vol. 206, pp. 343–353.CrossRefGoogle Scholar
  11. Eagles, G., The age and origin of the central Scotia Sea, Geophys. J. Int., 2010, vol. 183, no. 2, pp. 587–600.CrossRefGoogle Scholar
  12. Gainanov, A.G. and Panteleev, V.L., Morskaya Gravirazvedka (Marine Gravity Prospecting), Moscow: Nedra, 1991.Google Scholar
  13. Galindo-Zaldivar, J., Balanya, J., Bohoyo, F., Jabaloy, A., Maldonado, A., Martnez-Martnez, J., Rodriguez-Fernandez, J., and Surinach, E., Active crustal fragmentation along the Scotia-Antarctic plate boundary east of the South Orkney Microcontinent (Antarctica), Earth Planet. Sci. Lett., 2002, vol. 204, pp. 33–46.CrossRefGoogle Scholar
  14. Galushkin, Yu.I., Dubinin, E.P., and Sveshnikov, A.A., A nonstationary model of the thermal regime of axial zones of mid-ocean ridges:?formation of crustal and mantle magma chambers, Izv., Phys. Solid Earth, 2007, vol. 43, no. 2, pp. 130–147.CrossRefGoogle Scholar
  15. Livermore, R., Cunningham, A., Vanneste, L., and Larter, R., Subduction influence on magma supply at the East Scotia Ridge, Earth Planet. Sci. Lett., 1997, no. 150, pp. 261–275.Google Scholar
  16. Maldonado, A., Balanya, J.C, Bamolas, A., et al., Tectonics of an Extinct Ridge-Transform Intersection, Drake Passage (Antarctica), Marine Geophys. Res., 2000, vol. 21, pp. 43–68.CrossRefGoogle Scholar
  17. Maldonado, A., Barnolas, A., Bohoyo, F., et al., Contourite deposits in the central Scotia Sea: the importance of the Antarctic Circumpolar Current and the Weddell Gyre flows, Palaeogeogr., Palaeoclimatol., Palaeoecol., 2003, vol. 198, pp. 187–221.CrossRefGoogle Scholar
  18. Manea, M., Manea, V., Kostoglodov, V., and Guzman-Speziale, M., Elastic thickness of the oceanic lithosphere beneath Tehuantepec Ridge, Geofisica Internasional, 2005, vol. 44, no. 2, pp. 157–168.Google Scholar
  19. McKenzie, D.P. and Bowin, C., The relationship between bathymetry and gravity in the Atlantic Ocean, J. Geophys. Res., 1976, no. 81, pp. 1903–1915.Google Scholar
  20. Pelayo, A.M. and Wiens, D.A., Seismotectonics and relative plate motion in the Scotia Sea region, J. Geophys. Res., 1989, vol. 94, pp. 7293–7320.CrossRefGoogle Scholar
  21. Sandwell, D.T. and Smith, W.H.F., Marine gravity anomaly from Geosat and ERS-1 satellite altimetry, J. Geophys. Res., 1997, vol. 102, pp. 10039–10054.CrossRefGoogle Scholar
  22. Susini, S. and Donatis, M., 3d model of a sector of the South Scotia Ridge (Antarctica), Comput. Geosci., 2009, no. 35, pp. 83–91.Google Scholar
  23. Sykes, T.J.S., A Correction for sediment load upon the ocean floor: uniform versus varying sediment density estimations-implications for isostatic correction, Marine Geol., 1996, vol. 133, pp. 35–49.CrossRefGoogle Scholar
  24. Turcotte, D., and Schubert, G., Geodynamics, New York: Wiley, 1982.Google Scholar
  25. Teterin, D.E., Dubinin, E.P., Udintsev, G.B., Kol’tsova, A.V., and Domaratskaya, L.G., Major tectonic elements of the Scotia Plate, Oceanology, 2015, vol. 55, no. 2, pp. 236–244.CrossRefGoogle Scholar
  26. Udintsev, G.B. and Schenke, G.V., Ocherki geodinamiki Zapadnoi Antarktiki (An Outline of Geodynamics of the Western Antarctic), Moscow: GEOS, 2004.Google Scholar
  27. Udintsev, G.B., Beresnev, A.F., Kurentsova, N.A., et al., The Drake Passage and the Scotia Sea: The Ocean Gate of the Western Antarctic, in Vklad Rossii v Mezhdunarodnyi polyarnyi god 2007/08. Stroenie i istoriya razvitiya Litosfery (Contribution of Russia to International Polar Year 2007/08. Structure and History of Development of the Lithosphere), Leonov, Yu.G., Ed., Moscow-St. Petersburg: Paulsen Editions, 2010, pp. 64–88.Google Scholar
  28. Watts, A.B., The effective elastic thickness of the lithosphere and the evolution of foreland basins, Basin Res., 1992, no. 4, pp. 169–178.Google Scholar
  29. Watts, A.B., Isostasy and Flexure of the Lithosphere, Cambridge: Cambridge Univ. Press, 2001.Google Scholar

Copyright information

© Pleiades Publishing, Ltd. 2015

Authors and Affiliations

  • D. E. Teterin
    • 1
  • E. P. Dubinin
    • 2
  • G. B. Udintsev
    • 1
  1. 1.Vernadsky Institute of Geochemistry and Analytical ChemistryRussian Academy of SciencesMoscowRussia
  2. 2.Earth Science Museum (The Museum of Natural History)Moscow State UniversityMoscowRussia

Personalised recommendations