DUCTILE AND BRITTLE EXTENSION IN THE SOUTHERN LOFOTEN ARCHIPELAGO, NORTH NORWAY: IMPLICATIONS FOR DIFFERENCES IN TECTONIC STYLE ALONG AN ANCIENT COLLISIONAL MARGIN

• Main Authors: Andre C. Klein, Mark G. Steltenpohl, Willis E. Hames
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Lofoten; Norway; North Norway
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.540.2429; http://earth.geology.yale.edu/~ajs/1999/01.1999.02Klein.pdf

ABSTRACT. The Lofoten archipelago, north Norway, occupies the most inter-nal position of the Caledonian belt in northern Scandinavia, and rocks and structures exposed there are crucial to understanding processes of how the Baltic basement and its cover allochthons responded to continental lithospheric subduc-tion and subsequent continental separation. Relatively little is published about the structural and metamorphic development and especially the timing of these events; consequently, it is unknown how features exposed on these spatially isolated islands relate to those of the adjacent mainland. Rocks in Lofoten were affected by Caledonian regional metamorphism, and structures record tops-east contraction and later extension related to late- to post-Caledonian basement exhumation. Tops-west extension is preferentially developed in meter to km-scale ductile shear zones containing west-dipping extensional shear bands, west-verging rootless folds, and asymmetric feldspar porphyroclasts. West-plunging, sinistral-oblique elongation lineations in the mylonitic foliation are interpreted to indicate the line of transport. Mesoscopic backfolds are locally developed