Abstract:

Whether the Jinzi orogenic movement ever existed is a problem that in-volves the understanding of the structural evolution and mineral explorationin the Lower Yangtze region.At present,the focus of arguments is on the rea-lization of the origin of the carbonate breccia at the base of the Middle and Upper Triassic Huangmaqing Group.Proponents of the basal breccia advo-cate the existence of the movement,while that of the salt-solution brecciaor other secondary origins negate it.In this paper,the authors discuss the primary sedimentary origin of the breccia in terms of its sedimentary features,spatial distribution and occur-rence,and consider it to be a basal breccia.Besides,an analysis of the features of the carbonate breccia exposed at Mr.Yangfang,Chalukou,indicates that this kind of breccia can not beformed by the solution of gypsum and collapse of country rocks.