Abstract:

On the profile alonging Da River from Pacma to Vietnam-China Border, in the distribution space of Song Da aged Late Paleozoic, volcanic formations distributed independently, without 30 stratigraphic structure intercalated with sedimental rocks. Volcalnic bodies with composition of adesite, tuff-andesite agrromerate, riolite together with granite, granodiorite and diorite intrusions intruded and metamorphosed sedimental rocks of Song Da formations. According to Vietnamese Stratigraphical Standards as well as Geological Mapping Protocol, the authors suggest to use the formal Name “Song Da Complex” (Phức hệ Sông Đà) to describe the volcanic magma formations that has been separated from Song Da formation. The separating of volcanic magma formations in the maps into independent geological bodies in order to increase the using effectiveness and reality of Geological Maps in studied areas.