The Finnmarkian phase of the Caledonian Orogeny

The Kalak nappe complex of N Norway involves late Precambrian to Middle Cambrian sediments and a Precambrian gneiss basement on which the sediments were deposited. While the uppermost nappe in Finnmark was emplaced during the Silurian the members of the Kalak nappe complex were emplaced in late Cambrian/early Ordovician times during the Finnmarkian orogenic stage—probably the analogue of the Grampian stage of the British Caledonian. The tectonic-metamorphic events of the Finnmarkian stage were broadly coeval with the emplacement of basic and alkaline igneous bodies of the Seiland Igneous Province which were introduced from 552 ± 17 Ma (syn-D1) until 501 ± 27 Ma (late D2) and which themselves reflect magmatic evolution from tholeiitic to alkaline types.