Exploratory field work in the Lower and Middle Triassic of Svalbard — Diversity and Stratigraphy of Lower and Middle Triassic Ichthyosauria of Svalbard
Final Report Abstract
During this exploratory field trip, our international team, consisting of geologists and paleontologists from France, Germany, The Netherlands and China, was able to visit four different Lower and Middle Triassic fossil sites in different parts of Spitzbergen, Svalbard Archipelago. These sites comprise classical localities on Dickson Land (Sauriedalen) and around Marmiersfjellet (type locality of the Middle Triassic Botneheia Formation) but also more remote and rarely visited places such as Sørkapp (southernmost tip of Spitsbergen) and Agardhdalen in the eastern part of Spitsbergen. We were able to get familiar with the geology, of mainly the Lower Triassic Grippia and Fish Niveau (Vikinghøgda Formation). We found our hypothesis validated that vertebrate fossils are best found along the steep mountainsides. We were also able – as predicted by us – to locate remains of large ichthyosaurs in the Lower Triassic. In the Grippia Niveau at Agardhdalen (Roslagenfjellet) we found remains of a large (~3 m body size) and once complete ichthyosaurs that are heavily weathered. At Eistraryggen we found in the Grippia Niveau a centrum of about 6 cm in diameter that belonged to another large ichthyosaur (estimated body size of > 5m). Thus, large ichthyosaurs (likely cymbospondylids) had been present as early as the Early Triassic in Svalbard. In addition, at Agardhdalen we collected from the surface in the Grippia and Fish niveaus numerous vertebrate fossils in concretions as well as isolated vertebral centra to protect them from further weathering. These fossils nicely give an overview about the respective vertebrate fauna for each of the two horizons. Among this material are abundat remains of the ichthyosauromorph Grippia, which is so far only known by very rare and poorly preserved material.
