2020
On the the origin of the Yermak Plateau north of Svalbard, Arctic Ocean
100

The Yermak Plateau north of Spitsbergen and Morris Jesup Spur and rise north of Greenland relate to the Late Cretaceous-early Cenozoic interaction between an independent Greenland plate and the larger North American and European plates. We have recovered 21 new dredge hauls from three locations on the Yermak Plateau with an abundance of metasedimentary and gneissic rocks with strong affinities to known lithologies from northwest Spitsbergen. The continental outlier requires Paleogene dextral shear close to the coast of West Spitsbergen to accommodate opening of the Sophia Basin between the plateau and the continental margin. The postulated large-offset (100–150 km) shear zone (de Geer Fault) is supported by seismic velocity anomalies down to mid-crustal levels, a ubiquitous feature of known large-offset continental transform faults regardless of crustal rock composition. A continental sliver including the Yermak Plateau and Prins Karls Forland initially moved with Greenland along the de Geer Fault during the early Eocene stage of Eurasia Basin opening and facilitated opening of the Sophia Basin north of Spitsbergen by crustal extension. Later offset of the de Geer Fault north of Spitsbergen and formation of the Danskøya Basin in a transfer zone was probably induced by a restraining bend in the
Hornsund Fault Zone active at the same time. The 65 km-wide, circular-shaped, northeastern tip of the Yermak Plateau is a young volcanic feature formed between Chron 21 and -15 at the junction between the Gakkel Ridge and the Yermak continental block before separation of the Morris Jesup Spur and Yermak Plateau. The Yermak Plateau became part of the
European plate prior to Chron 13 as the Gakkel Ridge propagated into the Northeast Greenland margin and the subsequent dextral motion shifted west to the Hornsund Fault Zone. The de Geer Fault and the Hornsund Fault Zone may have been in existence at the same time.

yngve.kristoffersen[at]geo.uib.no
Print