Early paleozoic tectonics and paleogeography of the Eastern Arctic and Siberia: Review of paleomagnetic and geologic data for the De Long Islands

The structural features of the continental shelf and oceanic basin of the Eastern Arctic as well as its tectonic history are particularly controversial. The New Siberian Islands (NSI) archipelago is one of the few territories accessible for direct geologic study in this region. The De Long Islands occupy the northernmost part of the NSI archipelago and are situated at the junction of the major tectonic units of the Eastern Arctic. This, coupled with the lack of geologic information caused by the remoteness of the islands, leads to many debates concerning the tectonic affinity and relations of the De Long Islands with adjacent units. Here we review the geology and paleomagnetism for Cambrian-Ordovician rocks of the De Long Islands. The similarity of benthic fauna groups of the De Long and adjacent Anjou basins to the Siberian Taimyr-Verkhoyansk margin indicates that the De Long unit was close to Siberia. However, some detrital zircon groups indicate their non-Siberia provenances. In this review, based on paleomagnetic evidence, we propose a global tectonic reconstruction showing interactions and drift kinematics of the NSI and the nearby Arctic terranes as well as the cratons Siberia, Laurentia and Baltica from 510 to 450 Ma. We propose the existence of a New Siberian - Chukotka - Alaska carbonate platform - a large epicontinental basin between Siberia and Laurentia with a biogeographic connection to the Verkhoyansk shelf of Siberia and potential detrital provenances from Chukotka - Alaska. The mostly transform tectonic boundaries surrounding the platform enabled its constituent terranes to drift independently while preserving conditions for unimpeded migration of Siberian benthic fauna but not for Siberia-derived zircons. Moreover, its De Long margin developed up to the Ordovician period in a suprasubductional setting and perhaps had a tectonic connection with the Mendeleev Rise.