Structural Evolution of the Central and Southern Zones of the Eastern Taimyr Fold and Thrust Belt

Andrei Khudoley¹, Vasily Proskurnin², and Vladimir Verzhbitsky^3
1St.Petersburg State University, St. Petersburg, Russian Federation.
²All Russian Geological Research Institute, St. Petersburg, Russian Federation.
³Shirshov Institute of Oceanology RAS, Moscow, Russian Federation.

Central and southern zones of the Taimyr fold and thrust belt are accretionary belt and passive margin of the Siberian Craton correspondently. Their deformation history started in Neoproterozoic and continued up to Cenozoic.

The oldest structures are distributed in metamorphic rocks of the Central zone and are represented by strike-parallel shear zones with both strike-slip and thrust sense of shearing and complicated folds of different vergence. They predate or synchronous to ca. 850 Ma granites. Geometrically similar structures have been documented in a younger Neoproterozoic rocks unconformably overlapped by Vendian rock units.

Hercynian compression event was likely most intense to the north from the study area. Within the Central zone it resulted in formation of a wide transpression zone with “flower-type structure” of northwest- and southeast-vergent folds and thrusts. Available paleostress indicators show that formation of transpression zone was associated with dextral displacement. Hercynian structures are cut by ca. 250 Ma granites. Within the Southern zone, Hercynian compression event resulted in formation of a foreland basin. Some refolded thrusts in the southern zone are likely related to the Hercynian event as well.

Geometrical characteristics of thrusts and folds documented in Cambrian to Permian rock units of the Southern zone are very similar showing that they were formed during the same compression event. In the Tsvetkova Cape area deformation of Permian to Jurassic rocks also occurred in the same stress field and we infer that most of currently observed structures of the Southern zone and adjoining areas were formed during the Mesozoic compression event. During the Mesozoic compression event structures of the Central zone were reworked as well. Distribution of unconformities in the Mesozoic succession and composition of clastic rocks shows that Mesozoic deformations started in Jurassic whereas the main compression event was in late Early Cretaceous.

Although formation of Paleozoic passive margin was related to extension, related structures were reworked during compression events and have not been recognized. However, Late Cretaceous to Cenozoic normal faulting is widely distributed in the Tsvetkova Cape area pointing to post-orogenic reactivation of thrust as normal faults and formation of a set of normal faults approximately parallel to those of the Laptev Sea rift system.

 

AAPG Search and Discovery Article #90130©2011 3P Arctic, The Polar Petroleum Potential Conference & Exhibition, Halifax, Nova Scotia, Canada, 30 August-2 September, 2011.

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