The Lomonosov Ridge is a 1500 km long and 50-70 km wide submarine mountain chain that crosses the Arctic Ocean. The data showed evidence for substantial erosion on the crest of ridge down to ca 1-km present water depth. Ice grounding and/or currents were suggested as the most likely causes of this erosion. These discoveries called for more investigations and during the summer of 1999, the US Navy nuclear submarine, USS Hawkbill, collected acoustic data from the eroded areas under the auspices of the SCICEX program using sidescan swath bathymetric sonar and chirp sonar. These data showed glacial fluting and scouring of seafloor and large-scale glacial erosion of the ridge crest down to 1-km present water depth. Sediment core data made it possible to date the ice grounding on the Lomonosov Ridge to ca 150 000 years ago (Marine oxygen Isotope Stage 6). During 2003 more evidence for ice grounding was mapped on the Chukchi Borderland off Northern Alaskan margin. In collaboration with Scott Polar Research Institute and the Geological Survey of Denmark and Greenland during the International Polar Year (IPY) 2007/2008 we plan to map the seafloor of the heavily sea-ice covered areas of the Lomonosov Ridge north of Greenland for glacial features. This may provide the potential to decipher one more of the key pieces in the Arctic Ocean glacial puzzle.

Mapped glacigenic features in the Arctic Ocean and inferred directions of ice movement. Arrows show directions and lines orientations: orange = Polyak et al. (2001); red = Jakobsson (2000); green=Vogt et al. (1994). Black arrows show glacial iceberg directions and sources of late Quaternary sediments (Phillips and Grantz, 2001).White contour is the present 1000 m depth curve. Blue solid line outlines the ice-sheet extension 150 000 years ago (MIS 6) on the Barents and Kara Sea margin (Svendsen et al., 2004). The ice sheet extension 18 000 years ago in the Barents and Kara Sea is shown with a blue dashed line (Svendsen et al. (2004) and in North America with a gray dashed line (Dyke et al., 2002).
Mapped glacigenic features in the Arctic Ocean and inferred directions of ice movement. Arrows show directions and lines orientations: orange = Polyak et al. (2001); red = Jakobsson (2000); green=Vogt et al. (1994). Black arrows show glacial iceberg directions and sources of late Quaternary sediments (Phillips and Grantz, 2001).White contour is the present 1000 m depth curve. Blue solid line outlines the ice-sheet extension 150 000 years ago (MIS 6) on the Barents and Kara Sea margin (Svendsen et al., 2004). The ice sheet extension 18 000 years ago in the Barents and Kara Sea is shown with a blue dashed line (Svendsen et al. (2004) and in North America with a gray dashed line (Dyke et al., 2002).
“Chirp sonar record showing the mapped ice erosion on the Lomonosov Ridge”
“Chirp sonar record showing the mapped ice erosion on the Lomonosov Ridge”
 
 

Contact information:
Martin Jakobsson, martin.jakobsson@geo.su.se
Jan Backman, backman@geo.su.se

References
Dyke, A.S., Andrews, J.T., Clark, P.U., England, J.H., Miller, G.H., Shaw, J., and Veillette, J.J., 2002. The Laurentide and Innuitian ice sheets during the Last Glacial Maximum. Quaternary Science Reviews, v. 21, p. 9–13.

Jakobsson, M., Gardner, J.V., Vogt, P., Mayer, L.A., Armstrong, A., Backman, J., Brennan, R., Calder, B., Hall, J.K., and Kraft, B., 2005, Multibeam bathymetric and sediment profiler evidence for ice grounding on the Chukchi Borderland, Arctic Ocean, Arctic Ocean, Quaternary Research, in press.

Jakobsson, M, Siegert, M., and Paton, M., 2004, Is grounding of an ice shelf possible in the central Arctic Ocean? A modelling experiment, ICAM-IV, September 30-October 3, 2003, Conference Proceedings, in press.

Jakobsson, M., Løvlie, R., Arnold, E. M., Backman, J., Polyak, L., Knutsen, JO., and Musatov, E., 2001, Pleistocene stratigraphy and paleoenvironmental variation from Lomonosov Ridge sediments, central Arctic Ocean, Global and Planetary Change, v. 31, no. 1–4, p. 1–21.

Jakobsson, M., 1999, First high-resolution chirp sonar profiles from the central Arctic Ocean reveal erosion of Lomonosov Ridge sediments, Marine Geology, v. 154, p. 111–123.

Phillips, R.L., Grantz, A., 2001. Regional variations in provenance and abundance of ice-rafted clasts in Arctic Ocean sediments: implications for the configuration of late Quaternary oceanic and atmospheric circulation in the Arctic. Marine Geology, v. 172, p. 91–115.

Polyak, L., Edwards, M. H., Coakley, B. J. and Jakobsson, M., 2001, Ice shelves in the Pleistocene Artic Ocean inferred from glaciogenic deep-sea bedforms, Nature, v. 410, p. 453–457.

Svendsen, J.I., Alexanderson, H., Astakhov, V.I., Demidov, I., Dowdeswell, J.A., Henriksen, M., Hjort, C., Houmark-Nielsen, M., Hubberten, H.W., Ingólfson, O., Jakobsson, M., Kjær, K., Larsen, E., Lokrantz, H., Lunkka, J.P., Lyså, A., Mangerud, J., Maslenikova, O., Matioushkov, A., Murray, A., Möller, P., Niessen, F., Saarnisto, M., Siegert, C., Stein, R., Siegert, M.J., Spielhagen, R., 2004, The late Quaternary ice sheet history of Nortern Eurasia, Quaternay Science Reviews special QUEEN volume, Quaternary Science Reviews, v. 23, p. 1229–1271.

Svendsen, J.I., Alexanderson, H., Astakhov, V.I., Demidov, I., Dowdeswell, J.A., Henriksen, M., Hjort, C., Houmark-Nielsen, M., Hubberten, H.W., Ingólfson, O., Jakobsson, M., Kjær, K., Larsen, E., Lokrantz, H., Lunkka, J.P., Lyså, A., Mangerud, J., Maslenikova, O., Matioushkov, A., Murray, A., Möller, P., Niessen, F., Saarnisto, M., Siegert, C., Stein, R., Siegert, M.J., Spielhagen, R., 2004. Late Quaternary ice sheet history of Northern Eurasia. Quaternary Science Reviews, v. 23, p. 1229–1271.

Vogt, P.R., Crane, K., and Sundvor, E., 1994. Deep Pleistocene iceberg plowmarks on the Yermak Plateau: sidescan and 3.5 kHz evidence for thick calving ice fronts and a possible marine ice sheet in the Arctic Ocean. Geology, v. 22, no. 5, p. 403–406