A possible relationship between augen gneisses and postorogenic granites in S.E. Sweden

Augen gneisses occur east of the postorogenic Småland granites in south-eastern Sweden. These augen gneisses are generally folded conformably with the surrounding rocks but in several areas they seem to pass transitionally into the otherwise cross-cutting postorogenic granites. The augen gneisses in the Finspång area are suggested to be caps or down-pointing flukes of the postorogenic granites in a structure similar to one of Ramberg's (1967) centrifuged model experiments. Several factors suggest that these granites intruded as congealing magmas. The proposed evolutionary model has some features in common with the balloon tectonic model (Ramsay 1981). However, rather than the magma expanding an outer skin around a simple balloon-like structure, the concept is extended to include the magmatic inflation and distortion of the cap resulting also in down pointing, folded fluke structures.If the proposed relationship can be established, it follows that extensive metamorphism and deformation took place in southeast Sweden as a marginal effect of the intrusion of the Småland granites.