新疆北部阿尔泰造山带富蕴乌恰沟一带首次发现代表中、下地壳深变质作用的基性麻粒岩详细的野外和室内研究表明阿尔泰基性麻粒岩主要由粗粒和细粒的麻粒岩组成(SiO_2含量为47.83～53.57％)。两者的矿物组合相近,为斜方辉石+单斜辉石+斜长石+角闪石+黑云母角闪石和黑云母成分富镁,可能与岩石的成分富镁有关。基性麻粒岩的岩石地球化学成分显示其富Mg/(Mg+Fe~(2+))和亏损U,Th,K及Rh,而且其原岩为钙碱性玄武岩,是岛弧构造环境下形成的产物,矿物化学特征表明斜方辉石中Mg/(Mg+Fe~(2+))介于0.65～0.71之间,为紫苏辉石,具高MgO+FeO,低Al_2O_3和Ca/(Ca+Mg+Fe),而单斜辉石具低TiO_2和Al_2O_3的特点,说明它们皆为变质成因,部分角闪石和褐色黑云母富钛,指示它们为高温下形成的产物。这些特征证实了上述岩石为基性麻粒岩。角闪石和黑云母氟和氯含量较低以及水逸度较高,暗示其流体成分氟和氯在变质作用过程中不起主导作用。根据麻粒岩中矿物共生组合、期次和矿物温压计估算,麻粒岩形成的峰期和退变质温压条件分别为750～780℃,0.6～0.7GPa和590～620℃,0.23～0.37GPa,前者属高温中压条件。阿尔泰地区基性麻粒岩的发现为进一步研究阿尔泰地区深部下地壳的组成和结构以及深化阿尔泰地区、新疆北部甚至中亚地区大陆动力学过程和机制都具有重要意义 For the first time, the basic granulites, which represent the deep metamorphism of the middle and lower crust, have been found in the Altyn Tagh orogenic belt in the northern part of Xinjiang. Detailed field and laboratory studies indicate that the Altai-basic granulite is composed of coarse and fine granule Rock composition (SiO 2 content of 47.83 ~ 53.57%). The mineral assemblages of the two are similar. They are orthopyroxene + clinopyroxene + plagioclase + amphibole + biotite amphibole and biotite, which may be related to the magnesian composition of rock. Geochemical characteristics of basic granulites show that they are rich in Mg / (Mg + Fe2 +) and depleted in U, Th, K and Rh, and their original rocks are calc-alkaline basalts, The results show that the Mg / (Mg + Fe ~ (2+)) in orthopyroxene is between 0.65 and 0.71, and the peridotite has high contents of MgO + FeO, low Al 2 O 3 and Ca / (Ca + Mg + Fe). However, clinopyroxene has the characteristics of low TiO_2 and Al_2O_3, indicating that they are all metamorphic origin. Some hornblende and brown biotite are rich in titanium, indicating that they are products formed at high temperature. These features confirm that these rocks are basic granulites. The amphiboles and biotites have lower fluorine and chlorine contents and higher water vaporities, suggesting that their fluid components, fluorine and chlorine, can not play a dominant role in the metamorphism. According to the symbiosis of mineral assemblages in granulite, ephemerals and thermometers, the peak pressure and temperature of degenerated metamorphic rocks are 750 ~ 780 ℃, 0.6 ~ 0.7GPa, 590 ~ 620 ℃, 0.23 ~ 0.37GPa, the former is a high temperature and pressure conditions. The discovery of the basic granulite in the Altai area is of great significance for the further study of the composition and structure of the deep lower crust in the Altai region and the deepening of continental dynamics and mechanisms in the Altai region, northern Xinjiang and even the Central Asia