系统的元素及多元同位素地球化学研究表明,以西乌珠穆沁旗地区和塔河地区为代表的部分大兴安岭晚中生代火山岩地幔源区组分中存在明确的古老地块物质贡献.与大兴安岭其他地区晚中生代火山岩源区组分主要为新生地壳物质特征相比,塔河火山岩中的碎屑锆石记录了晚元古代和早古生代年龄;配套的微量元素和多元同位素特征则清晰地指示了上述两个地区火山岩的源区组分是在继承古老地块富集地幔的基础上叠加了古生代岛弧等新生地壳物质.上述研究首次为兴蒙造山带内存在前寒武古老地体以及该造山带组成特征提供了明确和系统的深部地球化学制约.晚中生代全球深部事件以及蒙古-鄂霍茨克洋闭合后的伸展作用,触发岩石圈地幔部分熔融,是本区晚中生代强烈火山活动成因可能的地球动力学背景. The systematic elemental and multivariate isotope geochemical studies show that there is a definite material contribution of the ancient block in the components of the mantle source of the late Mesozoic volcanic rocks in the part of Da Hinggan Mountains, which is represented by the West Wujumqinqin Banner and the Tahe area.Compared with other parts of the Greater Hinggan Mountains The components of the Mesozoic volcanic source are mainly characterized by the characteristics of the fresh crust. Detrital zircons from the Tahe volcanic rocks record the age of the Late Proterozoic and Early Paleozoic. The supporting trace elements and multivariate isotopes clearly indicate the above two The origin of the volcanic rocks in the area is based on the enrichment of the ancient mantle and the accumulation of new-generation crustal materials such as the Paleozoic island arc.The study above is for the first time that the Precambrian ancient terrane existed in the Xingmeng orogenic belt and the orogenic belt Features provide clear and systematic deep geochemical constraints.The late Mesozoic global deep events and the extension of the Mongolian-Okhotsk Ocean closure after the closure triggered the partial melting of the lithospheric mantle, which is a possible geodynamic source of the late Mesozoic intense volcanic activity in this area Learn background.