The Stuoragurra Fault, evidence of neotectonics in the Precambrian of Finnmark, northern Norway

Several fault lines, of Late Glacial or Holocene age, occur along an 80 km long zone trending SW-NE
on Finnmarksvidda. The faults appear as well defined, often linear steps in the otherwise smooth till
cover. Northeast of the lake of Iesjav'ri the fault crosscuts glaciofluvial deposits, indicating that at least
one section of the fault is of Holocene age. The maximum observed displacement is 7 metres. The western
block is depressed. Electromagnetic (VLF ) measurements indicate locally a southeasterly dip, which
implies that sections of the Stuoragurra Fault are reverse or low angle thrusts. Older fracture zones in
the area were identified by interpreting aeromagnetic data. This interpretation map yields distinct sets
of dislocations whose main directions are 30°W, 5°E and 42°E. It is concluded that the Late Quatemary
faults partly coincide with the older fault zones, but that Late Quatemary fracturing outside these zones
also occurs locally. The recent seismicity occurs along an elongate duster oriented NE-SW, about parallel
to the neotectonic structures. This indicates that the mechanisms which produced the faulting are possibly
still active. It is concluded that stress associated with spreading at the Mohns, Knipovich and Nansen
Ridges, viscous drag force at the base of the lithosphere and colliding resistance along the southern
border of the Eurasian plate are likely to be important contributors to the mechanism generating faults.
The release of these stresses could, however, be related to the deglaciation period.