Nappe and thrust structures in the Sparagmite region, southern Norway.
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- Artikler 
The Osen-Røa Nappe Complex is thrust upon a crystalline basement and a thin autochthonous sediment cover. The nappe complex is characterized by a sole thrust cutting up-section toward the SSE, by flats, ramps and contraction faults separating subordinate thrust sheets. Duplex geometry is present in the western part of the leading edge and within some minor thrust sheets. An arcuate fold system developed during the emplacement of the nappe, the Kvitvola Nappe, resting on the Osen-Røa Nappe Complex with a regional disconformity, may have been emplaced on an erosional surface and carried further by piggy-back transport. Another possibility is that the disconformity is the result of out-of-sequence thrusting when the Kvitvola thrust became reactivated. Post-thrust deformation gave rise to the Snødøla-Steinfjellet basement antiform and other undulations in the basement and broad synforms and antiforms in the nappe cover. The driving force of the thrusting is briefly discussed.