Abstract:There is a large-scale alkali-rich intrusive rock zone, with an NNE striking in linear distribution, in the coastal area of east Zhejiang. It is composed of alkali-feldspar granites and alkaline granites. The alkali-rich intrusive rocks are characterized by Si-high (SiO2>76%), alkali-rich(Na2O K2O>8.2%), Al-low (Al2O3<12.5%), Ca-and Mg-poor (CaO<0.4%,MgO<0.20%) and concentrations of Rb, Th(U),Nb (Ta), Zr, Zn,Ga, etc. The chondrite-normalized REE patterns exhibit a gently right-dipping V-type curve with a severe depletion in Eu. The characters arc essentially identical with those of alkaline granite in Kuiqi, Fujian and similar to those of the A-type granite in the achlan folded zone of southeast Australia. The, above studies indicate that the alkali-rich granite zone was formed as a result of the magmatic evolution at the late stage of the Yanshanian movement, controlled by a regional deep fracture, that is to say, its formation may be attributed to the upward intrusion of deep-source alkali-rich magma during the tension of the deep fracture on active continental margin.