天山石炭纪碰撞后裂谷火山岩是中国西北的一个大火成岩省。根据岩石地球化学数据,天山石炭纪碰撞后裂谷基性熔岩可以被分为两个主要岩浆类型:①低Ti/Y类型,分布于天山中段和东段,以低Ti/Y(<500)、Ce/Y(<15)、SiO_2(43％～55％)和相对高Fe_2O_(3T)(6.4％～11.5％)为特征;②高Ti/Y类型,分布于天山西段,以高Ti/Y(>500)、Ce/Y(>11)、SiO_2(49％～55％)和相对低Fe_2O_(3T)(5.8％～7.8％)为特征。研究表明,低Ti/Y和高Ti/Y熔岩的化学变异不能用一个共同母岩浆的分离结晶作用予以解释。天山石炭纪基性熔岩可能源于似OIB型软流圈地幔源(~(87)Sr/~(86)Sr)_t≈0.703～0.705,ε_(Nd)(t)≈+4～+7。地壳混染作用和大陆岩石圈地 The Tieshan Carboniferous post-collision Rift Volcanic Rock is a large igneous province in northwestern China. Based on the lithogeochemical data, the post-collision basic lava of the Tianshan Carboniferous can be divided into two major magmatic types: ① Low Ti / Y types distributed in the middle and eastern Tianshan Mountains with low Ti / Y (<500) , Ce / Y (<15), SiO 2 (43% -55%) and relatively high Fe 3 O 3 (6.4% -1 11.5%). The high Ti / / Y (> 500), Ce / Y (> 11), SiO 2 (49% -55%) and relatively low Fe 2 O 3 (5.8% -7.8%). Studies have shown that the chemical variation of low Ti / Y and high Ti / Y lavas can not be explained by the separation crystallization of a common parental magma. The Tianshan Carboniferous base lavas may originate from the mantle source (~ (87) Sr / ~ (86) Sr) _t≈0.703 ~ 0.705 and ε Nd (t) ≈ + 4 ~ + 7, Crustal contamination and continental lithosphere