680
Land-Ocean SYstems in the Siberian Arctic: Dynamics and History
eastern North Chukchi Basin. The main extension axis might be a continuation from the MidAtlantic Ridge via Baffin Bay and Makarov Basin toward the Mende1eev Ridge and Chukchi
Borderland. We also speculate that in that time the southern part of the Mendeleev Ridge was
rifted away from the De Long Block and the Toll' Rift, Chukchi Rift Basin and Charlie Rift
were formed.
Finally, in the Tertiary to Quaternary time the Laptev Rift System was formed in response to
the opening of the Eurasia Basin. This rifting started as early as 60-56 Ma or even earlier, and
the main rifts were formed by the end of the Eocene since that period is characterized by the
highest spreading rates (Savostin et aI., 1984a). Present-day extension still occurs along
Bel'kov Svyatoi Nos Rift but, probably, at a very low rate.
Thus we suggest that the spreading in the Arctic oceanic basins migrated westward during
Cretaceous-Cenozoic time and led to rifting and subsidence of the sedimentary rift basins on the
continental side as well as to separating and fragmentation of the marginal continental blocks:
the Chukchi Borderland, the Mendeleev and Lomonosov ridges.
Acknowledgments
This paper was prepared during the visits of S. Drachev at GEOMAR Research Center for
Marine Geosciences in the Kiel, Germany, in 1996 and 1997. We are grateful to Prof. J.
Thiede and Dr. H. Kassens who generously provided this opportunity. This work was partly
supported by the International Science Foundation (grant number M5UOOO), the German
Ministry of Education, Science, Research and Technology, (grant number 525 4003 03 G 0517
A) and the Executive Committee of the Nansen Arctic Drilling Program. G. L. Johnson was
supported by the Office of Naval Research.
References
Avetisov, G.P. (1993) Some questions of dynamic of the lithosphere of the Laptev Sea. Fisika Zemli, 5, 28-38
(in Russian).
Cook, D.B., K. Fujita and C.A. McMullen (1986) Present day plate interaction in northeast Asia; North
American, Eurasian and Okhotsk plates. Journal of the Geodynamics, 6, 33-51.
Drachev, S.S. and L.A. Savostin (1993) Ophiolites of the Bol'shoi Lyakhov Island (New Siberian Islands).
Geotektonika, 6, 33-51 (in Russian).
Drachev, S.S., L.A Savostin and I.E. Bruni (1995a) Structural pattern and tectonic history of the Laptev Sea
region. In: Kassens et al. (Editors), Reports on Polar Research, 175. Alfred Wegener Institute for Polar and
Marine Research, Bremerhaven, Germany, 348-366.
Drachev, S.S., L.A. Savostin, A.V. Elistratov and I.E. Bruni (1995b) New multichannel seismic results from
East Siberian Sea: Indigirka Bay to Jeanette Island profile. In: 5th Zonenshain Conference on Plate Tectonics,
Moscow, November 1995, Programme and Abstracts. Institute of Oceanology, Moscow, GEOMAR
Research Center, 42-43.
Embry, AF. and J. Dixon (1994) The age of the Amerasia Basin. In: D.K. Thurston and K. Fujita (eds.),
Proceedings of the 1992 International Conference on Arctic Margins. U.S. Dept. of the Interior Minerals
Management Service, OCS Study, 289-294.
Fujita, K. and J.T. Newberry (1982) Tectonic evolution of northeastern Siberia and adjacent regions:
Tectonophysics, 89, 337-357.
Fujita, K., F.W. Cambray and M.A. Velbel (1990) Tectonics of the Laptev Sea and the Morna rift systems,
northeastern USSR. In: A.F. Weber, D.A Forsyth, AF. Embry and S.M. Blanco (eds.), Arctic Geoscience.
Mar. Geol., 93, 95-118.
Fujita, K. and D. Cook (1990) The Arctic continental margin of eastern Siberia. In: A Grantz, L. Johnson and
J.F. Sweeney (eds.), The Geology of North America, vol. L, The Arctic Ocean Region. Geol. Soc. of Amer.,
Boulder, Co., 257-288.
Grachev, A.F. (1982) Geodynamics of the transitional zone from the Morna rift to the Gakke1 ridge. In: J.S.
Watkins and C.L. Drake (eds.), Studies in Continental Margin Geology. Am. Assoc. Pet. Geol. Mem., 34,
103-113.
Gramberg, I.S., V.V. Verba, G.A. Kudryavtzev, M.Yu. Sorokin and LJ. Kharitonova (1993) Crustal structure
Land-Ocean SYstems in the Siberian Arctic: Dynamics and History
eastern North Chukchi Basin. The main extension axis might be a continuation from the MidAtlantic Ridge via Baffin Bay and Makarov Basin toward the Mende1eev Ridge and Chukchi
Borderland. We also speculate that in that time the southern part of the Mendeleev Ridge was
rifted away from the De Long Block and the Toll' Rift, Chukchi Rift Basin and Charlie Rift
were formed.
Finally, in the Tertiary to Quaternary time the Laptev Rift System was formed in response to
the opening of the Eurasia Basin. This rifting started as early as 60-56 Ma or even earlier, and
the main rifts were formed by the end of the Eocene since that period is characterized by the
highest spreading rates (Savostin et aI., 1984a). Present-day extension still occurs along
Bel'kov Svyatoi Nos Rift but, probably, at a very low rate.
Thus we suggest that the spreading in the Arctic oceanic basins migrated westward during
Cretaceous-Cenozoic time and led to rifting and subsidence of the sedimentary rift basins on the
continental side as well as to separating and fragmentation of the marginal continental blocks:
the Chukchi Borderland, the Mendeleev and Lomonosov ridges.
Acknowledgments
This paper was prepared during the visits of S. Drachev at GEOMAR Research Center for
Marine Geosciences in the Kiel, Germany, in 1996 and 1997. We are grateful to Prof. J.
Thiede and Dr. H. Kassens who generously provided this opportunity. This work was partly
supported by the International Science Foundation (grant number M5UOOO), the German
Ministry of Education, Science, Research and Technology, (grant number 525 4003 03 G 0517
A) and the Executive Committee of the Nansen Arctic Drilling Program. G. L. Johnson was
supported by the Office of Naval Research.
References
Avetisov, G.P. (1993) Some questions of dynamic of the lithosphere of the Laptev Sea. Fisika Zemli, 5, 28-38
(in Russian).
Cook, D.B., K. Fujita and C.A. McMullen (1986) Present day plate interaction in northeast Asia; North
American, Eurasian and Okhotsk plates. Journal of the Geodynamics, 6, 33-51.
Drachev, S.S. and L.A. Savostin (1993) Ophiolites of the Bol'shoi Lyakhov Island (New Siberian Islands).
Geotektonika, 6, 33-51 (in Russian).
Drachev, S.S., L.A Savostin and I.E. Bruni (1995a) Structural pattern and tectonic history of the Laptev Sea
region. In: Kassens et al. (Editors), Reports on Polar Research, 175. Alfred Wegener Institute for Polar and
Marine Research, Bremerhaven, Germany, 348-366.
Drachev, S.S., L.A. Savostin, A.V. Elistratov and I.E. Bruni (1995b) New multichannel seismic results from
East Siberian Sea: Indigirka Bay to Jeanette Island profile. In: 5th Zonenshain Conference on Plate Tectonics,
Moscow, November 1995, Programme and Abstracts. Institute of Oceanology, Moscow, GEOMAR
Research Center, 42-43.
Embry, AF. and J. Dixon (1994) The age of the Amerasia Basin. In: D.K. Thurston and K. Fujita (eds.),
Proceedings of the 1992 International Conference on Arctic Margins. U.S. Dept. of the Interior Minerals
Management Service, OCS Study, 289-294.
Fujita, K. and J.T. Newberry (1982) Tectonic evolution of northeastern Siberia and adjacent regions:
Tectonophysics, 89, 337-357.
Fujita, K., F.W. Cambray and M.A. Velbel (1990) Tectonics of the Laptev Sea and the Morna rift systems,
northeastern USSR. In: A.F. Weber, D.A Forsyth, AF. Embry and S.M. Blanco (eds.), Arctic Geoscience.
Mar. Geol., 93, 95-118.
Fujita, K. and D. Cook (1990) The Arctic continental margin of eastern Siberia. In: A Grantz, L. Johnson and
J.F. Sweeney (eds.), The Geology of North America, vol. L, The Arctic Ocean Region. Geol. Soc. of Amer.,
Boulder, Co., 257-288.
Grachev, A.F. (1982) Geodynamics of the transitional zone from the Morna rift to the Gakke1 ridge. In: J.S.
Watkins and C.L. Drake (eds.), Studies in Continental Margin Geology. Am. Assoc. Pet. Geol. Mem., 34,
103-113.
Gramberg, I.S., V.V. Verba, G.A. Kudryavtzev, M.Yu. Sorokin and LJ. Kharitonova (1993) Crustal structure