Tectonic Transport Directions, Shear Senses and Deformation Temperatures Indicated by Quartz c-Axis Fabrics and Microstructures in a NW-SE Transect across the Moine and Sgurr Beag Thrust Sheets, Caledonian Orogen of Northern Scotland

Moine metasedimentary rocks of northern Scotland are characterized by arcuate map patterns mineral lineations that swing progressively clockwise from orogen-perpendicular E-trending in greenschist facies mylonites above the thrust on foreland edge Caledonian Orogen, to S-trending at higher structural levels and metamorphic grades hinterland. Quartz c-axis fabrics measured a west east coast transect demonstrate developed parallel maximum principal extension direction therefore track local tectonic transport direction. Microstructures document progressive change top N shearing hinterland W edge. Field relationships indicate domain was least 55 km wide before later horizontal shortening km-scale W-vergent folds detach underlying thrust. Previously published data had largely ceased 430 Ma, while preliminary isotopic age suggest occurred ~470–450 Ma. In addition, end our normal-sense down-SE close peak temperatures ~420 Ma may be related closing stages Scandian deformation, metamorphism cooling/exhumation.