| Popis: |
The structural fabrics recorded from Devonian rocks and substrate in the Hasteinen area, Western Norway, show near E-W trends. In the Devonian rocks these fabrics are a consequence of post-depositional regional folding at a considerable depth, presumably attended by the aquisition of an thermoviscous (TVRM) or thermochemical (TCRM) remanence (group A). Post or possibly late syntectonic group A remanences (declination=210, inclination = +18, α95=9) constitute the principal remanence in both Devonian rocks and their substrate, whereas a younger group B magnetization (declination=047, inclination=+59, α95=7) relates to early Mesozoic shearing. The palaeomagnetic (group A) and structural data from the Hasteinen and Kvamshesten Old Red Sandstone Massifs favor a regional compressive N-S shortening event (Svalbardian-Solundian), which probably occurred during latest Devonian times. Some recent extensional-basin models, appealing to listric-normal faulting to account for both the sedimentation and the subsequent deformation of the Western Norwegian Devonian rocks, are rejected on the basis of inadequate structural information. |
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