Wood Bay Formation
The Wood Bay Formation is a geologic formation found on the island of Spitsbergen, Svalbard in Norway. It preserves fossils dating back to the Pragian and Emsian stages of the Devonian period.
Stratigraphy
The Wood Bay Formation is divided into two main areas: the Woodfjorden area in the north and the Dicksonfjorden–Austfjorden area in the south. In the Woodfjorden area, the formation is further split into the Sigurdfjellet, Kapp Kjeldsen, Keltiefjellet, and Stjørdalen divisions, which are distinguished by the types of fish fossils found there. The Dicksonfjorden–Austfjorden area is divided into the Austfjorden, Dicksonfjorden, and Verdalen members based on differences in sedimentary features. These differing methods of classifying the formation's sub-units have led to difficulty in determining how one area corresponds to the other.
Paleoenvironment
The Wood Bay Formation was likely coastal and may represent an estuarine or fjord-like environment. The presence of a Lingula fossil recovered from the formation might suggest some degree of marine influence.
Fossil content
Acanthodians
Acanthodians are a group of stem–chondrichthyans found in Paleozoic deposits around the world. They are commonly represented in the fossil record by their spines and scales. The Acanthodian fauna of the Wood Bay Formation is not as well understood as the other animal groups present, but Xylacanthus grandis, the largest known acanthodian, is exclusively found here.
Agnathans
Agnathans are by far the most species–rich and well–known animal group present in the Wood Bay Formation. Osteostracans alone account for over one third of the total genera present in the formation. All Agnathans known from the formation are considered "Ostracoderms", an informal grouping of armored jawless fish from the Paleozoic.
Osteichthyans, or bony fish, are primarily represented by sarcopterygians in the Wood Bay Formation. Osteichthyans in general are poorly represented at the formation compared to other animal groups.
Placoderms
Placoderms are a group of armored fish that lived during the Late Silurian and Devonian periods of the Paleozoic. They represent the second most well–known group of animals from the Wood Bay Forrmation.
Invertebrates
Invertebrate fossils from the Wood Bay Formation are scarce and are mostly represented by microfossils.