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.

I n this note we draw attention to data which may require major revision of Dalradian stratigraphy and structure in northeast Scotland. The Central Highland sequence of the Dalradian and the Keith Division ( Read 1955 ) of Banffshire are separated from the metasediments of the Banff Division by gneisses. These are referred to as the Cowhythe Gneiss ( Read 1923 ), Queens Hill Gneiss (Harris & Pitcher 1975), Donside and Ellon Gneiss ( Read 1955 ) and Inzie Head Gneiss ( Read & Farquhar 1956 ) after the main areas of outcrop. The reader is referred to Read (1955 , pl. 1) where the general distribution of the gneisses is shown. Their relationships to the Central Highland succession are often complicated by the large granitic intrusions of the post-tectonic Younger Granite suite. The generally accepted model for the region interprets the gneisses as migmatites developed from the Ben Lui and Ben Lawers schists (e.g. Read 1955 , Harris & Pitcher 1975). Further they are considered to represent the migmatitic core of the Tay Nappe (e.g. Ashworth 1975 ). Read (1955) originally considered that the rocks of his Banff Division lay on a lag-surface (the Boyne Line) above the gneisses. The great recumbent fold of which the Banff Division formed the upper limb was called the Banff Nappe, and was considered to be a continuation of the Tay Nappe ( Read 1955 ). Recent investigations by the authors reveal a sharp tectonic break between the Dalradian rocks of the Central Highlands/Keith Division and the gneisses. This break is marked by discordance and a major

SummaryRb–Sr whole-rock isochron ages from shale horizons in the Late Pre-Cambrian tillite succession in Varangerfjord, Northern Norway, are presented. Although data from the Stappogiedde Formation, which overlies the tillite horizons, give a Caledonian, metamorphic age of 530±50 m.y., ages obtained from shales occurring between and below the tillites are believed to represent the approximate times of deposition of the sediments. An age of 810±90 m.y. for the Tanafjord Group enables this group to be correlated with the Upper Torridonian and the age of 668±23 m.y. for the Nyborg Formation, which is taken as the age of the Varanger Ice Age, allows a tentative correlation to be made with the Egan and Marinoan Glaciation in Australia.

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The metamorphic rocks forming the area are divided into four groups separated by easterly dipping shear zones. The two western groups are orthogneisses and the eastern two are metasedjments. The structures indicate movements from east to west with the most wdterly group of gneisses having been a stable block during the movements. The metamorphic and structural events in the area are considered to be part of the Caledonian Orogeny. A Devonian granophyre is intruded into the metamorphic rocks. Small areas of Devonian type sediments occur overlying the metamorphic rocks.