Glacial geomorphology of the Central Arctic Ocean: the Chukchi Borderland and the Lomonosov Ridge

2008 ◽  
Vol 33 (4) ◽  
pp. 526-545 ◽  
Author(s):  
Martin Jakobsson ◽  
Leonid Polyak ◽  
Margo Edwards ◽  
Johan Kleman ◽  
Bernard Coakley
Keyword(s):  
Arctic Ocean ◽  
Lomonosov Ridge ◽  
Glacial Geomorphology ◽  
Central Arctic Ocean ◽  
Chukchi Borderland

scholarly journals Ice-shelf damming in the glacial Arctic Ocean: dynamical regimes of a basin-covering kilometre-thick ice shelf

2017 ◽  
Vol 11 (4) ◽  
pp. 1745-1765 ◽  
Author(s):  
Johan Nilsson ◽  
Martin Jakobsson ◽  
Chris Borstad ◽  
Nina Kirchner ◽  
Göran Björk ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Ice Sheet ◽  
Lomonosov Ridge ◽  
Fram Strait ◽  
Ice Shelf ◽  
Interior Region ◽  
Central Arctic Ocean ◽  
One Dimensional ◽  
Grounding Line ◽  
The Mean

Abstract. Recent geological and geophysical data suggest that a 1 km thick ice shelf extended over the glacial Arctic Ocean during Marine Isotope Stage 6, about 140 000 years ago. Here, we theoretically analyse the development and equilibrium features of such an ice shelf, using scaling analyses and a one-dimensional ice-sheet–ice-shelf model. We find that the dynamically most consistent scenario is an ice shelf with a nearly uniform thickness that covers the entire Arctic Ocean. Further, the ice shelf has two regions with distinctly different dynamics: a vast interior region covering the central Arctic Ocean and an exit region towards the Fram Strait. In the interior region, which is effectively dammed by the Fram Strait constriction, there are strong back stresses and the mean ice-shelf thickness is controlled primarily by the horizontally integrated mass balance. A narrow transition zone is found near the continental grounding line, in which the ice-shelf thickness decreases offshore and approaches the mean basin thickness. If the surface accumulation and mass flow from the continental ice masses are sufficiently large, the ice-shelf thickness grows to the point where the ice shelf grounds on the Lomonosov Ridge. As this occurs, the back stress increases in the Amerasian Basin and the ice-shelf thickness becomes larger there than in the Eurasian Basin towards the Fram Strait. Using a one-dimensional ice-dynamic model, the stability of equilibrium ice-shelf configurations without and with grounding on the Lomonosov Ridge are examined. We find that the grounded ice-shelf configuration should be stable if the two Lomonosov Ridge grounding lines are located on the opposites sides of the ridge crest, implying that the downstream grounding line is located on a downward sloping bed. This result shares similarities with the classical result on marine ice-sheet stability of Weertman, but due to interactions between the Amerasian and Eurasian ice-shelf segments the mass flux at the downstream grounding line decreases rather than increases with ice thickness.

Pleistocene stratigraphy and paleoenvironmental variation from Lomonosov Ridge sediments, central Arctic Ocean

2001 ◽  
Vol 31 (1-4) ◽  
pp. 1-22 ◽  
Author(s):  
M Jakobsson ◽  
R Løvlie ◽  
E.M Arnold ◽  
J Backman ◽  
L Polyak ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Lomonosov Ridge ◽  
Central Arctic Ocean

scholarly journals Central Arctic Ocean paleoceanography from ~ 50 ka to present, on the basis of ostracode faunal assemblages from SWERUS 2014 expedition

2017 ◽  
Author(s):  
Laura Gemery ◽  
Thomas M. Cronin ◽  
Robert K. Poirier ◽  
Christof Pearce ◽  
Natalia Barrientos ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Large Scale ◽  
Late Quaternary ◽  
Atlantic Water ◽  
Environmental Indicators ◽  
The Arctic ◽  
Lomonosov Ridge ◽  
Central Arctic Ocean ◽  
Ice Conditions

Abstract. Late Quaternary paleoceanographic changes in the central Arctic Ocean were reconstructed from a multicore and gravity core from the Lomonosov Ridge (Arctic Ocean) collected during the 2014 SWERUS-C3 Expedition. Ostracode assemblages dated by accelerator mass spectrometry (AMS) indicate changing sea-ice conditions and warm Atlantic Water (AW) inflow to the Arctic Ocean from ~ 50 ka to present. Key taxa used as environmental indicators include Acetabulastoma arcticum (perennial sea ice), Polycope spp. (productivity and sea ice), Krithe hunti (partially sea-ice free conditions, deep water inflow), and Rabilimis mirabilis (high nutrient, AW inflow). Results indicate seasonally sea-ice free conditions during Marine Isotope Stage (MIS) 3 (~ 57–29 ka), rapid deglacial changes in water mass conditions (15–11 ka), seasonally sea-ice free conditions during the early Holocene (~ 10–7 ka) and perennial sea ice during the late Holocene. Comparisons with faunal records from other cores from the Mendeleev and Lomonosov Ridges suggest generally similar patterns, although sea-ice cover during the last glacial maximum may have been less extensive at the southern Lomonosov Ridge at our core site (~ 85.15° N, 152° E) than farther north and towards Greenland. The new data also provide evidence for abrupt, large-scale shifts in ostracode species depth and geographical distributions during rapid climatic transitions.

scholarly journals Ice-shelf damming in the glacial Arctic Ocean: dynamical regimes of a basin-covering kilometre thick ice shelf

2017 ◽  
Author(s):  
Johan Nilsson ◽  
Martin Jakobsson ◽  
Chris Borstad ◽  
Nina Kirchner ◽  
Göran Björk ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Ice Sheet ◽  
Lomonosov Ridge ◽  
Fram Strait ◽  
Ice Shelf ◽  
Interior Region ◽  
Central Arctic Ocean ◽  
One Dimensional ◽  
Grounding Line ◽  
The Mean

Abstract. Recent geological and geophysical data suggest that a one-kilometre thick ice shelf extended over the glacial Arctic Ocean during Marine Isotope Stage 6, about 140 000 years ago. Here, we theoretically analyse the development and equilibrium features of such an ice shelf, using scaling analyses and a one-dimensional ice-sheet–ice-shelf model. We find that the dynamically most consistent scenario is an ice shelf with a nearly uniform thickness that covers the entire Arctic Ocean. Further, the ice shelf have two regions with distinctly different dynamics: a vast interior region covering the central Arctic Ocean and an exit region towards the Fram Strait. In the interior region, which is effectively dammed by the Fram Strait constriction, there are strong back stresses and the mean ice-shelf thickness is controlled primarily by the horizontally-integrated mass balance. A narrow transitions zone is found near the continental grounding line, in which the ice-shelf thickness decreases offshore and approaches the mean basin thickness. If the surface accumulation and mass flow from the continental ice masses are sufficiently large, the ice-shelf thickness grows to the point where the ice shelf grounds on the Lomonosov Ridge. As this occurs, the back stress increases in the Amerasian Basin and the ice-shelf thickness becomes larger there than in the Eurasian Basin towards the Fram Strait. Using a one-dimensional ice-dynamic model, the stability of equilibrium ice-shelf configurations without and with grounding on the Lomonosov Ridge are examined. We find that the grounded ice-shelf configuration should be stable if the two Lomonosov Ridge grounding lines are located on the opposites sides of the ridge crest, implying that the downstream grounding line is located on a downward sloping bed. This result shares similarities with the classical result on marine ice-sheet stability of Weertman, but due to interactions between the Amerasian and Eurasian ice-shelf segments the mass flux at the downstream grounding line decreases rather than increases with ice thickness.

Towards ground truthing exploration in the central Arctic Ocean: a Cenozoic compaction history from the Lomonosov Ridge

2010 ◽  
Vol 22 (2) ◽  
pp. 215-235 ◽  
Author(s):  
M. O'Regan ◽  
K. Moran ◽  
C. D. P. Baxter ◽  
J. Cartwright ◽  
C. Vogt ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Lomonosov Ridge ◽  
Central Arctic Ocean ◽  
Ground Truthing
Sign in / Sign up

Export Citation Format

Share Document