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The Problem of the Opening of the Arctic Basin Jaime Toro- West Virginia University

The Problem of the Opening of the Arctic Basin Jaime Toro- West Virginia University Collaborators : Elizabeth Miller (Stanford), George Gehrels (Arizona), Jeff Amato (New Mexico State), Ken Bird (USGS) Funding : EXXON-Mobil, BP, PRF, WVU, Stanford,. Arctic Basins. Russia. Alaska.

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The Problem of the Opening of the Arctic Basin Jaime Toro- West Virginia University

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  1. The Problem of the Opening of the Arctic Basin Jaime Toro- West Virginia University Collaborators: Elizabeth Miller (Stanford), George Gehrels (Arizona), Jeff Amato (New Mexico State), Ken Bird (USGS) Funding: EXXON-Mobil, BP, PRF, WVU,Stanford,

  2. Arctic Basins Russia Alaska Alpha-Mendeleev R. Lomonosov Ridge Amerasian Basin Canada Eurasian Basin Greenland Europe Bathymetry: IBCAO, 2000

  3. Russia Alaska Magnetic Data, GSC Greenland

  4. Lomonosov Ridge Kristoffersen et al., 2002

  5. Amerasian Basin Opening Models Late Cretaceous Restoration

  6. Rotational Model (Grantz et al. 1990)

  7. Rotational Model Restoration Grantz et al. (1990)

  8. Comparison of the Stratigraphy of the North Slope Basin to the Sverdrup Basin Embry, 1990

  9. MEGA-SEQUENCE North Slope Stratigraphy K. Bird, USGS

  10. Prince Patrick Island Canada Basin North Slope Brooks Range

  11. Seismic Line R12 along the North Slope Coast Barrow Arch NE Brookian Sequence SW Beaufortian Ellesmerian Franklinian Sequence

  12. Upper Triassic Lower Triassic Carboniferous Seismic Line R12 along the North Slope Coast Barrow Arch SW NE Walakpa#1 Peard#1 S. Barrow#1 Brookian Sequence Franklinian Sequence

  13. L. Trias. Perm. L. Jur. Carb. R12 North Slope Brooks Range

  14. Prince Patrick Brock Is. MackenzieKing Is. Prince Patrick Is. 77o 76o Melville Is. Eglington Is. After Brent and Harrison, 2004

  15. Lawver et al. (2002) 150 MaLate Jurassic

  16. Lawver et al. (2002) 120 MaEarly Cretaceous Lomonosov is a strike slip boundary Alpha Mendeleev is a hot spot track

  17. Magnetic anomalies Free Air Gravity Russia Russia Greenland Greenland Alaska Alaska Magnetic Data, GSC Arctic Gravity Project , 2008

  18. Alaska Arctic Gravity Project , 2008

  19. Arctic Alaska-Chukotka Rotational model Arctic Alaska-Chukotka

  20. We are stuck!

  21. Detrital Zircon Geochronology

  22. Laser Ablation- Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS) Analyses by George Gehrels, University of Arizona

  23. Cumulative Probability Plots 485 • Analyze 100 grains (if possible) • Discard young ages with high errors on U/Pb ratios • Discard old ages with discordance >20% Probability 320 260 Zircon Age (Ma)

  24. Cape Lisburne Sample Sites for Triassic Sediments: 2 Chukotka 4 3 5 Wrangel Is. 1 Brooks Range N. Verkhoyansk 6 6 Sverdrup Basin Miller, Toro et al., 2006

  25. Detrital Zircon Ages from Triassic Sandstones of the Arctic Region 5. Brooks Range 6. N. Sverdrup Basin 1. Verkhoyansk 2. Chukotka 3. Wrangel 4. Lisburne

  26. Lawver et al. (2002) 1 150 MaLate Jurassic Brooks Range 2 4 3 5 6

  27. Late Cretaceous Paleo-Pacific

  28. 1 2 3 5 4 6 Early Cretaceous

  29. 17 21-22 Chukchi Borderland Mendeleev ridge Lomonosov ridge Alpha Ridge Bathymetry: IBCAO, 2000

  30. Seismic Data AcrossMendeleevRidge Line 17 Line 22 Line 21 Dove, 2007

  31. Arctic Ridges Basin and Range At the same scale

  32. Doesn’t look very much like other hot-spot tracks.. Hawaii Emperor Alpha- Mendeleev Tristan da Cunha Emperor-Hawaii

  33. Lebeneva-Ivanova et al. (2006) Seismic velocities for Mendeleev - It’s thick (34 km); Alpha is 38, - So, not oceanic crust (5-7 km) - It’s mostly fast (6.5-7.5), so mafic

  34. It’s velocity structure is similar to that of the Aleutians (Holbrook et al. 1999) Norwegian Voring Basin > 7 km/sec Or a rifted continental margin with a lot of early volcanism… Gernigon et al.: http://www.mantleplumes.org/VM_Norway.html

  35. Plate tectonics matters!

  36. United Nations Convention on the Law of the Seas (Unclos) • Arctic countries can claim the seabed beyond 200 nautical miles if that seabed is a natural extension of their continental shelf.

  37. Conclusions • N. Alaska restores to the Canadian Arctic by rotation but… • Chukotka rotates independently • Rifting pattern was complex • Ridges in the Arctic basin probably contain fragments of extended continental crust • The Siberian shelf also underwent considerable extensional deformation

  38. Alaska Russia Lomonosov Ridge Bathymetry: IBCAO, 2000 Barents Shelf Greenland

  39. Defining the Shelf Edge • The foot of the continental slope • 1% sediment thickness • 100Miles from the 2,500m isobath • 350 Miles from the coast

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