Emplacement of rapakivi granite and syenite by floor depression and roof uplift in the Palaeoproterozoic Ketilidian orogen, South Greenland

In the Palaeoproterozoic Ketilidian orogen of South Greenland, tabular intr usions of the rapakivi granite suite exposed at Graah Fjelde, Lindenow Fjor d and Qernertoq, and a Mesoproterozoic syenite of the Gardar province expos ed at Paatusoq, were emplaced by a combination of roof uplift and floor dep ression. The strain associated with the emplacement of the intrusions mainl y involved redistribution of mass vertically within the lithosphere. Space for the emplacement of the rapakivi plutons was not created during regional extension on low-angle, ductile shear zones as claimed by some previous wo rkers and there is no evidence that emplacement of the intrusions coincided with extensional collapse of the orogen following crustal thickening. The rapakivi granites post-dale peak metamorphism in the orogen by 35-46 Ma and their contacts cross-cut and clearly post-date intense, hat-lying D1/D2 fa brics that formed by partitioning of deformation into are-normal and are-pa rallel components during oblique convergence.