ON THE QUESTION CONCERNING THE MECHANISM OF GRANITE-GNEISS DOMES - ARC-RELATED THRUSTS OR STRUCTURES OF EXTENSION - (COMMENTS TO THE PAPER BY SIZYKH,V.I. ON THE PROBLEM OF THE ZAGAN GLASTOMELANGE)

The hypothesis of are-related thrusts in Transbaikalia is critically r eviewed. These thrusts, recognized on the basis of occurrence of speci fic gently dipping shear zones, which are called <<blastomelange>>, ar e supposed to be present in marginal parts of granite-gneiss domes and to be connected with the evolution of the latter. The results of deta iled geological and structural investigation make it possible to inter pret these shear zones as fragments of gently dipping normal faults, c onnected with processes of Late Mesozoic continental extension. The ab ove-mentioned granite-gneiss domes are Cordilleran-type metamorphic co re complexes.