A NEW MAP OF ARCTIC LITHOSPHERE

We reviewed the current state-of-knowledge associated with Arctic crust, crustal-scale discontinuities and their ages, as well as the characteristics of the lithosphere as a whole using available published geological and geophysical data. Discrete lithospheric domains and the principal tectonic events shaping them were identified, characterized, and compiled to form the basis for our new map of Arctic lithosphere.

Phanerozoic evolution of the Arctic continental lithosphere cored by three large Precambrian cratons is resulted from continent–continent collisions or continent accretion due to terrane amalgamation, and rift events in the late Devonian–early Carboniferous, Permo-Triassic, Jurassic, Early Cretaceous, and Late Cretaceous, and Cenozoic. The later are related to orogenic collapse, back-arc extension, or intracontinental extension associated with breakup of Pangea and Eurasia and culminated in ocean formation. At least two (Permo-Triassic and Aptian) mantle plume events resulted in underplating and weakening the pre-existing lithosphere. Large areas of submarine, hyperextended continental crust and exhumed mantle developed along the Amerasia Basin margins especially in the northern East Siberian and Chukchi seas.

Points that remain highly disputed include the following:

• timing and plate kinematics associated with Amerasia Basin formation

• offshore extent of the Norwegian Caledonides

• location of the Uralian fold belt beneath thick sedimentary cover in the Kara-Yamal region and its relationship to the Late Paleozoic Taimyr fold belt

• relationship between the Siberian Craton, Taimyr and Verkhoyansk fold belts offshore in the Laptev Sea

• age and boundaries of the DeLong Massif in the northern East Siberian Sea and its relationship with Kotel’nyi Island geology

• location of the northern limit of Late Mesozoic compressional deformation across the East Siberian Arctic Shelf

• occurrence of Caledonian/Ellesmerian-age deformation on Wrangel Island, the New Siberian Islands and in the Severnaya Zemlya Archipelago

• offshore extent of the South Anyui Suture

Further progress in understanding Arctic lithosphere evolution will be especially advanced by new investigations of Arctic islands, as well as by offshore seismic, sampling and drilling campaigns.