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甘肃大红山北角闪石岩体是塔里木板块东部新发现的一类镁铁质-超镁铁质岩体,通过野外观察、岩矿鉴定及地球化学研究,发现其岩浆分异不明显、岩石类型单一、组分为角闪石岩、全岩,w(SiO_2)=41.64%~50.83%、w(K_2O)/w(Na_2O)=0.45~0.66、w(K_2O)+w(Na_2O)=1.02%~2.81%,属亚碱性拉斑玄武岩系列,具有岛弧环境地球化学特征.采用LA-ICP-MS锆石U-Pb法获得年龄为273.6土4.8Ma.反映早二叠世受北侧古亚洲洋的汇聚碰撞,塔里木板块东南缘处于汇聚碰撞的岛弧环境向相对稳定的后造山环境方向演化阶段.
The Dapingshan North Cape amphibolite body in Gansu is a newly discovered mafic-ultramafic rock body in the eastern part of Tarim platelands. Through field observation, rock mineral identification and geochemical study, it is found that there is no significant difference between the magmatic rocks and the rocks The results showed that the composition of the rock is amphibole-rock, the whole rock is composed of hornblende rock, w (SiO_2) = 41.64% -50.83%, w (K_2O) / w (Na_2O) = 0.45-0.66, w_ (K_2O) + w % ~ 2.81%, belongs to the sub-alkaline tholeiite series and has the characteristics of island arc environment geochemistry.The age of 273.6 earth 4.8 Ma was obtained by LA-ICP-MS zircon U-Pb method, The converging collision of the ancient Asian oceans and the southeastern margin of the Tarim plate are in the evolutionary stage of the relatively stable post-orogenic environment toward the island arc environment where collisions collide.