The regions mentioned above record A-type magmatism with similar radiogenic isotopic composition. But, overall they are interpreted to be emplaced in the regional Grenvillean Convergence. If it was a convergence, then how the mantle-related magma origin can be justified. An extensional setting within the convergence zone? Was there a slab break off? collapse, or roll back of descending slab at 1.1 Ga. Otherwise, how one can justify the alkaline A type magmatism, lamprophyres and syenites within the overthickened crust which show limited zircon inheritance of older crust and Hf isotopic composition is radiogenic?