Аннотация:The numerous current hypotheses on structural
evolution of the present day Arctic require validation
using data from regional geological studies. We are
focusing on terrigenous deposits of Triassic age,
which are the key to correlate geological events from
the Eastern Arctic and the Verkhoyansk-Kolyma and
Anyui-Chukotka fold systems. Triassic deposits
of the Verkhoyansk–Kolyma fold system formed
along the eastern margin of the Siberian continent.
In the Anyui-Chukotka fold system, Triassic
deposits accumulated on the southern margin of the
Chukotka microcontinent. In present day structure
heavily deformed sedimentary complexes of the two
passive margins are brought closely together as a
result of collision. The Siberian continent collided
with the Kolyma – Omolon superterrane to form
the Verkhoyansk–Kolyma fold belt. The Anyui-
Chukotka fold system was formed as the result of
collision between the Siberian continent and the
Chukotka microcontinent associated with opening
of the Canada Basin within the Amerasia Basin.
The main results of our studies are: the directions of
sedimentary supply and shelf zone progradation in
the present day structure of theVerkhoyansk region
and Chukotka differ by almost 180°. Changes in the
sandstone mineral composition during the Triassic
provide evidence of different source provinces for
deposits of the Verkhoyansk and Chukotka passive
margins. Changes in the chemical composition
imply different evolutionary patterns of the rocks.
Compositions of detrital zircon assemblages show
dominant spikes of different ages: Verkhoyansk
region is dominated by Proterozoic assemblages,
and Chukotka by Phanerozoic ones. The level and
type of deformation in both cases is represented by
folds-and-thrusts of different vergence.