The 2014 expedition
The Early to Middle Triassic vertebrates of Svalbard – mapping and documentation
Some of the first ichthyosaurs from the Triassic worldwide were collected by the Nordenskiöld expeditions to Svalbard in 1864 and 1868. The fossils were collected in what is now known as the Blanknuten Member of the Botneheia Formation, and were described by Hulke in 1873. Hulke assigned the very fragmentary material to two new species, a large form named Ichthyosaurus polaris and a smaller one Ichthyosaurus nordenskioeldii. The latter was later placed in the mixosaurid family first within the genus Mixosaurus and then within Phalarodon.
The goal of the 2014 expedition was to do a sedimentological log of the Botneheia sand Vikinghøgda formations on the slopes of the mountains of Botneheia and Marmierfjellet and locate fossil layers for excavation the following four years.
A better understanding of the geology, higher resolution of the stratigraphy and description of the taphonomy are crucial for increasing our understanding of the formations . All of the discovered articulated specimens are from a high section of the Botneheia Formation. The association of fossils in the upper part of the Botneheia Formation demonstrates a special taphonomic environment. Issues like the high organic content in the sediment and abundant trace fossils (Thalassinoides), ammonoid biostratigraphy and a rich benthic fauna of bivalves (Daonella) needs further study.
New material of mixosaurid ichthyosaurs will help us to understand several aspects of Triassic ichthyosaur evolution. Even the validity of the Svalbard species Phalarodon nordenskioeldii has been debated for many years and is now considered a nomen dubium, due to non-diagnostic type material. The problematic taxonomy of Phalarodon nordenskioeldii will be one of the main focuses of the project, with new material collected.
Classically the following four levels with vertebrate fossils are described from the Lower to Middle Triassic of Svalbard:
- “Fish Niveau” ” Lusitaniadalen Member, Vikinghøgda Formation, about 250 million years
- “Grippia Niveau” Vendomdalen Member, Vikinghøgda Formation, about 249 million years
- “Lower Saurian Niveau” Vendomdalen Member, Vikinghøgda Formation, about 247 million years
- “Upper Saurian Niveau” Blanknuten Member, uppermost Botneheia Formation and the boundary beds to the Tschermakfjellet Formation, about 237 million years
The field party successfully located the four levels of vertebrate remains in the two formations and did surface collecting. Approximately 700 fragments of ichthyopterygians, sauropterygians, bony fish and sharks were collected. Two bonebeds (at Grippia and Lower Saurian levels ) and one locality with complete mixosaurids (at Upper Saurian level) were found and documented for further excavation.
Jørn H. Hurum, Patrick Druckenmiller, Øyvind Enger, Stig Larsen, Tommy Wensås, Aubrey Jane Roberts, Magne Høyberget, Bjørn Lund, Victoria Engeschiøn Nash, Inghild Halvorsen Økland, Øyvind Hammer, Hans Arne Nakrem