A revised heterostracan-based ichthyostratigraphy of the Wood Bay Formation (Lower Devonian, Spitsbergen), and correlation with Russian Arctic archipelagos

ABSTRACT Spitsbergen shows a several kilometers thick, mostly siliciclastic Devonian sequence. In this sequence, the Wood Bay Formation represents a typical Old Red Sandstone megafacies unit of Early Devonian age (Pragian-Emsian). It outcrops in the Andree Land Block (often wrongly designated as the “main Devonian graben”) in NW Spitsbergen. Its stratigraphy has been mostly established in two areas of this block, that is, in the Woodfjorden area in the north, and in the Dicksonfjorden-Austfjorden area in the south. A revision of the pteraspidiform heterostracan vertebrates has been carried out in both areas. Eight different fossil assemblages are defined, five for the Woodfjorden area (WA), and three for the Dicksonfjorden-Austfjorden area (DAA), that enable the correlation of the Sigurdfjellet and Kapp Kjeldsen “faunal divisions” of the lower Wood Bay Formation (in WA) with the Austfjorden Member (in DAA), and the Keltiefjellet “faunal division” of the upper Wood Bay Formation (in WA) with the Dicksonfjo...