EARLY TO MIDDLE DEVONIAN PALEOGEOGRAPHIC LOCATION OF SVALBARD, NORWAY

The paleogeographic location of Svalbard during the Early to Middle Devonian Period is critical to further our understanding of the tectonic and magmatic evolution of the Paleozoic Arctic. We present new sedimentary provenance data, including detrital zircon U-Pb ages, from samples of the Mimerdalen Section of the Andrée Land Basin, near Pyramiden, Spitsbergen. The Mimerdalen section represents the most complete stratigraphic representation of Devonian strata in Svalbard, with the ca. 1 km thick Mimerdalen Subgroup lying atop the ca. 3 km thick Wood Bay Formation. Units sampled were from the Pragian and Emsian Wood Bay Formation, as well as Givetian strata of the Mimerdalen Subgroup, identifiable colloquially as part of the Old Red Sandstone (ORS). The basal strata of the Wood Bay Formation lie unconformably atop the pre-Devonian basement in the Dickson Land region where the Mimerdalen section is located. Prior research has helped to define the depositional and structural context of the Andrée Land Basin strata, providing us the opportunity to further constrain the provenance of these deposits. Detrital zircon results and lithologic information from the Early Devonian strata indicate a proximal source region derived from nearby basement. A large population of ages from 940-1730 Ma consistent with local Pre-Caledonian sources, coupled with paleocurrent indicators, suggest the sediment was transported via fluvial systems from south and west of the basin. The Wood Bay samples and a basal sample from the Givetian Estheriahaugen member of the Tordalen Formation have a large Caledonian (ca. 410-460 Ma) component. However, a sample of the upper Estheriahaugen not only lacks the Caledonian ages, but also has a prominent population of ages in the 2590-2850 Ma range, possibly due to the tectonic reworking of the underlying basement. These results are consistent with recent research suggesting deposition of these rocks within the Northeast Greenland Caledonides, where they were located before being translated into their current position by post-collisional, orogen-parallel sinistral strike-slip movement along the Breibogen-Bockfjorden fault zone.