Reconstruction of the Grampian episode in Scotland: its place in the Caledonian Orogeny

Chemical composition and K–Ar age of Phengite from Barrovian metapelites, Loch Leven, Scotland

“…480-430 Ma; e.g. Kelley, 1988;Oliver, 2001). This is consistent with the idea that the age documents the time of phengite formation during Barrovian metamorphism .…”

“…480-430 Ma, based on 40 Ar-39 Ar, K-Ar, Rb-Sr and Sm-Nd dating (e.g. Dempster, 1985;Elias et al 1988;Kelley, 1988;Dallmeyer et al 2001;Oliver, 2001). The rocks in the Loch Leven area belong to the Appin and Grampian Groups, and comprise twelve stratigraphic types from structural bottom (the Eilde Flags) to top (the Appin Phyllite) (Roberts, 1976;Roberts and Treagus, 1977) (Fig.…”

Palaeoproterozoic to Neoproterozoic growth and evolution of the eastern Congo Craton: Its role in the Rodinia puzzle

“…4b), a scenario not too dissimilar to the Ordovician-Silurian arc accretion/collision events along eastern Laurentia, namely the Grampian and Appalachian events (e.g. Oliver, 2001;Murphy and Keppie, 2005). Continental-marginarc magmatism in Southern Malawi dated between 1040 and 999 Ma , indicates that subduction-related magmatism continued after arc-accretion (Fig.…”

PLATINUM-GROUP ELEMENTS IN ORDOVICIAN MAGMATIC Ni Cu SULFIDE PROSPECTS IN NORTHEAST SCOTLAND

“…The Younger Basic rocks were emplaced into Neoproterozoic metasedimentary rocks of the Dalradian Supergroup at 4709 Ma, coincident with the later stages of amphibolitie facies metamorphism in the country rocks (Dempster et al 2002). The emplacement of the Younger Basic intrusions was part of the Grampian orogenic episode (~480-465 Ma) that is postdated by isostatic uplift (465 -435 Ma) and the 'main' phase of Caledonian orogenesis in Scotland ending at ~395 Ma (Oliver 2001). The Grampian orogenic episode may relate to the subduction of a backarc basin (Highland Border back-arc), or the collision of the Midland Valley Arc with Laurentia due to the subduction of the northern Iapetus Ocean (Oliver 2001).…”

“…The emplacement of the Younger Basic intrusions was part of the Grampian orogenic episode (~480-465 Ma) that is postdated by isostatic uplift (465 -435 Ma) and the 'main' phase of Caledonian orogenesis in Scotland ending at ~395 Ma (Oliver 2001). The Grampian orogenic episode may relate to the subduction of a backarc basin (Highland Border back-arc), or the collision of the Midland Valley Arc with Laurentia due to the subduction of the northern Iapetus Ocean (Oliver 2001). Either way, in relation to the Younger Basic magmatism, both models imply that partial melting of the upper mantle was subduction-related and this is broadly consistent with the low ratio of high-field-strength elements to light-rare-earth elements found in these rocks (Thompson et al 1984).…”