New Paleomagnetic Data for the Franz Josef Land Archipelago and their Tectonic Consequences

Abstract:

On the base of field work on the Franz Josef Land archipelago (FJL) in 2010 and 2011 the new paleomagnetic data are obtained from the Jurassic-Early Cretaceous magmatic complexes. Main focus of this work was concentrated on the Early-Jurassic basalts widely represented on the Hooker island [1]. Together with the previous data [2] statistically reasonable paleomagnetic pole for the age boundary of 190 million years for the FJL is received (PLat.=62.4; PLon.=140.2; dp/dm=5.5/5.0; N=13). Paleomagnetic data allow to assume that the position of the FJL relative to the Europe in the Early Jurassic significantly differs from the present one. But to the Early Cretaceous it reached relative position very close to the presently observed [2]. We suggest that at least during Early-Middle Jurassic there was rifting processes between the North Barentz terrane (FJL and (may be) Svalbard) and the other part of the European tectonic domain. This rift was accompanied by shifting of the FLJ to the north-eastward on about 500 km.

Also obtained paleomagnetic data agree with a hypothesis assuming that the FJL was passing over the Icelandic-Siberian hot spot during Jurassic-Cretaceous time: main paleolatitudes correspond to the Island’s present latitude and the paleolatitude of the Siberian trapps. Paleomagnetic study of FJL has a reconnaissance character and cannot lead to any ultimate deductions as the data is obviously not enough. And further work on the basaltic covers of the archipelago seems to be very promising. Research was supported by grant RFBR 13-05-00177.

 1. Karyakin Yu.V., Shipilov E.V. Geochemical Specialization and the ⁴⁰Ar/³⁹Ar Age of Basaltoid Magmatism in the Aleksandra Land, Northbrook, Hooker, and Hayes Island (Franz Josef Land Archipelago) // Doklady Akademii Nauk, 2009, Vol.425, No.2, P. 213-217 (in Russian).

2. Bragin V.Yu., Karyakin Yu.V., Mikhaltsov N.E. The Franz Josef Land archipelago: reconnaissance paleomagnetic data // Large igneous provinces of Asia: mantle plumes and metallogeny (Irkutsk, Russia Aug., 20-23, 2011): Abstract vol. - Irkutsk: Petrographica, 2011. - P. 40-43.