Architecture and geodynamic evolution of the Svalbard Archipelago, the Yermak Plateau and the Fram Strait oceanic Province from deep seismic experiments
Between 1997 and 1999 new seismic refraction data were acquired in the region of the Svalbard Archipelago. These experiments were carried out by a German, Polish, Norwegian and Japanese cooperation. The resultant seismic velocity profiles give new insight into the general crustal structure of Svalba...
| Main Author: | |
|---|---|
| Format: | Thesis |
| Language: | unknown |
| Published: |
2003
|
| Subjects: | |
| Online Access: | https://epic.awi.de/id/eprint/6046/ https://hdl.handle.net/10013/epic.39232 |
| Summary: | Between 1997 and 1999 new seismic refraction data were acquired in the region of the Svalbard Archipelago. These experiments were carried out by a German, Polish, Norwegian and Japanese cooperation. The resultant seismic velocity profiles give new insight into the general crustal structure of Svalbard, its western continental margin, the Yermak Plateau and the adjacent Fram Strait in the northern Atlantic oceanic realm.A fundamental observation of this study is that the Yermak Plateau north of the Svalbard Archipelago exhibits no evidence for elevated magmatic activity due to the presence of a mantle plume. The seismic velocity structure reveals none of the characteristic features of a rifted-volcanic margin. The southern Yermak Plateau shows instead a mid-crustal detachment that supports theories of Oligocene extensional movements and parallel development of pull-apart-like basins. Only slight amounts of melt have been intruded due to crustal thinning and subsequent decompressive melting.Svalbard's different Caledonian terranes cannot be distinguished on the basis of their seismic structure. Stretching of continental crust, associated with the Cenozoic rifting of western Svalbard, is confined to the western terrane. The boundary between the western and central Caledonian terranes is overprinted by the Cenozoic Western Spitsbergen Orogenic Belt. This belt exhibits remarkably low seismic velocities within the upper brittle crust down to a depth of ~20 km, that leads to the assumption that the rock fabric is intensively sheared and faulted. Proposed flower structure models, in a transpressive tectonic regime, seem plausible for the evolution of the orogenic belt. The coincidence of Caledonian and Cenozoic (sinistral and dextral) shear zones may indicate the possible reactivation of old sutures.The continental margin off western Svalbard is more segmented than previously thought. Off Van Mijenfjorden a rifted margin is observed. The continent-ocean transition off Kongsfjorden reveals a steep and abrupt change in ... |
|---|