The Taimyr fold belt, Arctic Siberia: timing of prefold remagnetisation and regional tectonics Trond H. Torsvik a,b,c, * , Torgeir B. Andersen d a VISTA, c/o Geodynamics Centre, NGU, Leiv Eirikssons vei 39, N-7491 Trondheim, Norway b Department of Mineralogy and Petrology, Lund University, Lund S-222 333, Sweden c Institute of Petroleum Technology and Applied Geophysics, NTNU, N-7494 NTNU, Norway d Department of Geology, University of Oslo, P.B. 1047 Blindern, 0316 Oslo, Norway Received 29 August 2001; accepted 9 April 2002 Abstract Late Precambrian and Palaeozoic platform sediments from the Central –South Taimyr Peninsula (Arctic Siberia) are all remagnetised. The remagnetisation is prefold and is related to thermal remagnetisation caused by Taimyr Trap magmatism. The remagnetisation age is estimated to 220 – 230 Ma and, hence, is considerably younger than the ca. 251 Ma age for the main body of Siberian Trap flood basalts. The folding that affected the Taimyr region platform sediments also included the Taimyr ‘‘Traps,’’ hence, relegating Taimyr deformation to post-Mid Triassic time, and most probably, to a Late Triassic age. This shows that whilst thrusting terminated in the Urals during the Permian, crustal shortening continued in Taimyr, Novaya –Zemlya and the South Barents Sea, well into the Mesozoic. D 2002 Elsevier Science B.V. All rights reserved. Keywords: Taimyr; Arctic Siberia; Palaeozoic; Palaeomagnetism; Remagnetisation 1. Introduction The Taimyr Peninsula of Arctic Siberia has tradi- tionally been divided into three main parts: North, Central and South Taimyr. North Taimyr, together with Severnaya Zemlya (Fig. 1a–b), contains the Kara microcontinent that is suggested to have collided with Siberia (Central and South Taimyr) during the Late Palaeozoic Uralian Orogeny (Vernikovsky, 1996, 1997). Central Taimyr has been defined by the pres- ence of an accreted terrane (Faddey Terrane) with ophiolites (800–740 Ma) and its collision with South Taimyr was suggested to have occurred at around 600–570 Ma. The sedimentary succession of Central and South Taimyr records the development of a stable platform from the Upper Riphean to the late Carbon- iferous (Vernikovsky, 1997); the platform sequence unconformably covers the accreted Faddey Terrane of Central Taimyr and was used to provide an upper age limit for the timing of amalgamation of the Central and South Taimyr units. The change in the Central– South Taimyr depositional environment from that of stable platform to a foreland basin setting with con- tinental sandstone deposition has been related to the Late Palaeozoic to Early Mesozoic collision of the amalgamated Central –South Taimyr blocks with the Kara microcontinent. 0040-1951/02/$ - see front matter D 2002 Elsevier Science B.V. All rights reserved. PII:S0040-1951(02)00274-3 * Corresponding author. Geological Survey of Norway, Strate- gic Research and Development, Leiv Erikssons vei 39, N-7491 Trondheim, Norway. Fax: +47-73-904494. E-mail address: trond.torsvik@ngu.no (T.H. Torsvik). www.elsevier.com/locate/tecto Tectonophysics 352 (2002) 335– 348