Kinematic History and Tectonic Evolution of the Amerasian Basin: Investigating Palaeo-Plate Boundaries around the Chukchi Borderlands
Abstract
The multi-stage opening of the Arctic Ocean's Amerasian Basin is only partially understood due to the difficulty of utilizing traditional marine geologic and geophysical techniques in ice-covered waters. While the kinematic development of the Eurasian Basin is well-understood to be the northernmost extension of the Mid-Atlantic Ridge, the history of the morphologically complex Amerasian Basin may be due to multiple events, significantly complicating interpretation of its history. Any detailed model for the opening of the Amerasian Basin must both incorporate structures that accommodate spreading as well as explain the tectonic mechanisms that drove basin development. Cretaceous-age tholeiitic flood basalts and associated radiating dike swarms of the High Arctic Large Igneous Province (HALIP), found along the basin margin, provide a tectonic mechanism and geometry to substantiate sound reconstruction. Detailed models need also consider pre-existing zones of weakness such as the deformation front of the Devonian Caledonides, which may underlie Barents Shelf sediments (Gee and Bogolepova, 2003). Reactivation of these ancient structural trends along this suture zone may explain the motion of Mendeleev Ridge as it rifted from Lomonosov Ridge and created the rectangular pull-apart basin between them. We propose a revised plate model for the development of the Amerasian Basin. A Cretaceous magmatic source localized under the Alpha Ridge accompanied the onset of rifting. This generated the HALIP radiating dike swarms and tholeiitic flood basalts found on the DeLong Islands, Svalbard, Franz Joseph Land, Greenland, Sverdrup Basin and, possibly, the Alpha and Mendeleev Ridges. New bathymetric and sub-bottom profiling data also suggests the existence of igneous dikes on Chukchi Cap. The subsequent development of a triple junction resulted in dilational opening of the Canada Basin. Spreading was accommodated by the migration of the southern edges of the northeastern Siberian shelf along large right lateral transform faults in the South Anyui Suture Zone allowing for crustal "escape" toward the Pacific subduction zone. Bathymetric, aeromagnetic and gravity data support the triple junction idea as well as a complimentary zone of left lateral transform motion along the northern Alaska margin and southern edge of the Chukchi Borderlands which also accommodated spreading.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- Bibcode:
- 2007AGUFM.T11E..05B
- Keywords:
-
- 3010 Gravity and isostasy (1218;
- 1222);
- 3045 Seafloor morphology;
- geology;
- and geophysics;
- 8157 Plate motions: past (3040);
- 9315 Arctic region (0718;
- 4207)