Basement-cover relationships and regional correlations of the Caledonian nappes, eastern Hinnøy, N. Norway

The westernmost outcrops of Caledonian nappes on eastern Hinnøy, Lofoten-Vesterålen, are correlated with the Lower, Middle and Upper Allochthons. Below the Caledonian allochthon in the Storvatn area, Hinnøy, autochthonous/parautochthonous conglomerates and quartzites rest on a basement of Precambrian granites. These metasediments are correlated with the Vendian to Cambrian Torneträsk Formation occurring along the Caledonian Front and around tectonic windows. In the Storvatn area, the basement with its sedimentary cover is overlain by the allochthonous L-M Complex correlated with the Lower and the Middle Allochthons. The L-M Complex consists of a series of nappes; the lower ones consist of thrust together sheets of granite, arnphibolite facies and greenschist facies lithologies, and the upper ones of sheets of granite covered by greenschist facies quartzites and micaschists. The latter allochthonous quartzites and micaschists are suggested to be western correlatives of the Tornetrask Forrnation. A metamorphic and structural discontinuity related to a major thrust separates the amphibolite facies schists, arnphibolites and marbles of the Upper Complex from the L-M Complex. The Upper Complex is correlated with the Upper Allochthon. Structural relations imply a translation of Caledonian nappes a cross the Lofoten-Vesterålen basement by a process of thin-skin tectonics involving the upperrnost basement and its sedimentary cover.