1. Phanerozoic Tectonic Evolution of the Chukotka-Arctic Alaska Block: Problems of the Rotational Model Boris A. Natal’in Istanbul Technical University

3. Components of the Chukotka- Arctic Alaska block Arctic Alaska superterrane Arctic Alaska superterrane Seward Terrane Seward Terrane York Mountains terrane York Mountains terrane Bennett-Barrovia block Chukotka fold belt Nutesyn arc The Bennett-Barrovia block continues to Alaska as the Hammond subterrane, York Mountains terrane, and Nixon Fork terrane AlaskaChukotka

5. Proposed Boundaries of Arctic Alaska- Chukotka Plate (dotted line)

7. Late Jurassic, 150 Ma Lawver et al. 2002 1000 km Kotelnyi Severnaya Zemlya Kotelnyi

8. Bol. Lyakhovsky 122±7 K-Ar Younger than late Jurassic 291±62 Sm-Nd 133-139 Ma K-Ar

10. Gravity gradients Pushkarev et al., 1999

15. Geophysical data Franke et al. (2004): - Blagoveschensk basin is absent - the shelf of the East Siberian Sea is epicontinental platform Puskarev et al. (1999): - Low standing basement - Densities are characteristic for consolidated crust Puskarev et al., 1999 SN

16. Bennett-Barrovia block: Basement Granites 750 Ma Metamorphism 655-594 Ma Granites 699 Ma Granites 705 Ma Orthogneiss 681 and 676 Ma Orthogneiss 650 Ma

17. Correlation with Taimyr Bennett-Barrovia pre-collision volcanics – 633±25 Ma syncollisional granites – 750-699 (650?) Ma metamorphism – 630 Ma assimilated crust – 1.3- 1.5 Ga (Nelson et al., 1989) and 0,8-1.0 (Karl et al., 1989) Devonian granites – 0.7- 1.6 Ga Bennett-Barrovia pre-collision volcanics – 633±25 Ma syncollisional granites – 750-699 (650?) Ma metamorphism – 630 Ma assimilated crust – 1.3- 1.5 Ga (Nelson et al., 1989) and 0,8-1.0 (Karl et al., 1989) Devonian granites – 0.7- 1.6 Ga Taimyr pre-collision volcanics – 630-615 Ma syncollisional granites – 630 Ma metamorphism – 655-594 assimilated crust – 0.84-1.1 Ga

18. 1 2 3 4 5 6

19. Correlation of Paleozoic sections

20. Barrovia (Sherwood, 1992)

21. Taimyr and Severnaya Zemlya (Russia) Thick pile of the upper Proterozoic-Cambrian flysch Evaporites in the Ordovician and Upper Silurian and Devonian Early Paleozoic fossils are different

22. Franklinian structures sandstone, tuffaceous sandstone, shale, conglomerate, lavas and dikes of basalt, andesite, and diabase Ordovician to Silurian oceanic and magmatic arc rock assemblages Margin of N. America Deformed Ordovician and Silurian slates

23. Pre-late Devonian subduction related magmatic arc at the eastern edge of BB gravity magnetic Herman and Zerwick, 1998

26. The late Silurian-early Devonian collision of the Bennett-Barrovia block

27. Devonian-early Carboniferous subduction zone along the southern margin of the Bennett-Barrovia block 398-383 Ma euhedral zircons of 370-360 Ma 381 Ma 375 ± 11 Ma 376 ± 37 Ma ε Nd is +0.2 and -0.3 360 Ma Visean

28. Back arc basin of the Devonian arc ε Nd -7 Tanatap basin - deep water shale and fine grained turbidite - high-K andesitic tuffs with ε Nd -7 Alyarmaut - Calc-silicates, quartzite, mafic tuffs Alyarmaut - Calc-silicates, quartzite, mafic tuffs Belkovskyi-Nerpalakh Trough - Upper Devonian to Lower Carboniferous limestone, shale, sandstone, conglomerate, mafic dikes and sills Belkovskyi-Nerpalakh Trough - Upper Devonian to Lower Carboniferous limestone, shale, sandstone, conglomerate, mafic dikes and sills Brooks Range - Devonian extensional basin (the Beaucoup F.) Brooks Range - Devonian extensional basin (the Beaucoup F.)

30. Position of continents is after Lawver et al. (2002); 390 Ma

31. Carboniferous-Permian Wrangel Island - shallow marine Carboniferous limestones grading up into Permian slates Wrangel Island - shallow marine Carboniferous limestones grading up into Permian slates (~2100 m) - basin slopes to the south Chukotka - Lower Carboniferous conglomerates grading up into arkose sandstones, shale, and limestones (4500 m) - Permian rocks are unknown - Source area is expected in the south - Source area have to be rich in granites

32. Modified after Grantz et al. (1991) 4.5 km molasse orogeny Many km lithic turbidite mafic magmatism rifting 0.1-0.2 km shale, chert, sandstone stable shelf

33. Carboniferous collision? Position of continents is after Lawver et al. (2002); 330 Ma

34. Opening of the South Anyui ocean Position of continents is after Lawver et al. (2002)