MANTLE-DERIVED GAS RESERVOIR AND ITS FORMING RULES IN EASTERN CHINA

Along the Tancheng-Lujiang deep fracture belt,some mantle-derived natural gas pools are formed in the east part of China,consisting mainly of mantle CO_2 and mantle rare gas,and with the characteristics of high contents of CO_2 and He,high δ~13C_CO_2 value and R/R_a,and so on.In terms of the tectonic settings of mantle-derived gas reservoirs in eastern China,the paper expounds some researches and applications concerning mantle-derived fluid geochemistry,mantle-derived gas identifying signs,main controlling factors of mantle gas reservoirs,as well as the time and space distribution rule of mantle-derived gas pools,and also simply recounts the new research trends in identifying synthetically mantle-derived gas and finding favorable areas,and some key problems in them.