关键词: 松潘—阿坝盆地, 基底, 火成岩, 岩石化学特征, 成藏条件, 油气勘探远景

Abstract: The lithochemical characteristics of Bikou Group,Pengguan complex rock and Kangding complex rock located in the north,east and south parts of Songpan-Aba Basin are very similar,which shows that the above three magmatic rocks originated from the same geological environment,and the tectonic events occurred in the Mesoproterozoic-Neoproterozoic period and involved the whole basin.The combination analysis of geophysical data,such as magneto-electro-telluric data,gravity data,and the lithochemical data confirm that there exists a stable basement in Songpan-Aba Basin.The hypometamorphic rock is distributed around the Ruoergai,and the epimetamorphic rock and the magmatic rock are distributed around the margin of the basin.The three intrusions mentioned above consist of stable basement.On the basis of solid basement,two plays of the Eopaleozoic and the Neopaleozoic-Triassic reservoirs were developed.The reservoir-forming condition of the Eopaleozoic play is better than that of the Neopaleozoic-Triassic play.The reservoir-forming condition in the middle uplift zone of the basin is the best.The Triassic formation is very thick,which results in the high exploration expenditure and risk in this area.Though the Motianling uplift only developed the Eopaleozoic play,the stable geological setting with weak tectonic activities since the Miocene time benefited to the preservation of petroleum.Therefore the Motianling uplift is an available exploration area in Songpan-Aba Basin.

Key words: Songpan-Aba Basin, basement, magmatic rock, lithochemical characteristics, reservoir-forming condition, petroleum exploration potential