The Dalradian rocks of the Highland Border region of Scotland

Mobility of gold during metamorphism of the Dalradian in Scotland

“…Schist formation of the Argyll Group (Fig. 2), which is reported to contain more semipelite and less psammitic schist than the Glen Lethnot Grit (Tanner et al, 2013). The metamorphic grade increases from the chlorite zone proximal to the Highland Boundary Fault through the biotite, garnet, staurolite and kyanite zones to the sillimanite zone in the north (Fig.…”

Origin, age, and significance of deep‐seated granulite‐facies migmatites in the Barrow zones of Scotland, Cairn Leuchan, Glen Muick area

“…The earliest collisional episode in this orogeny was the mid-Ordovician Grampian Event, which resulted from the accretion of an island arc system (the Midland Valley Terrane) to the southeastern edge of the Laurentian continental margin (the Grampian Terrane) ( Figure 1; Dewey & Mange, 1999;McKerrow, MacNiocaill, & Dewey, 2000;Soper, Ryan, & Dewey, 1999). The pelitic-to-psammitic sedimentary protoliths of the classical Barrow zone metamorphic sequence (the Dalradian Supergroup) formed on this Laurentian passive margin prior to ocean closure (Dewey, 1969;Harris & Pitcher, 1975;Tanner et al, 2013). The beginning of arc-continent collision was recorded by ophiolite obduction onto the Laurentian margin at 490 AE 4 Ma (K-Ar hornblende; Chew et al, 2010), with a U-Pb-corrected Ar-Ar white mica age of c. 488 Ma obtained from deformed biotite-grade metasedimentary units (Viete, Hermann, Lister, & Stenhouse, 2011;Viete, Oliver, Fraser, Forster, & Lister, 2013) likely marking the onset of crustal thickening and initiation of Barrovian metamorphism.…”