碳酸岩是一类富含碳酸盐矿物（体积＞50％），SiO2含量少于20％的岩浆岩，尽管碳酸岩起源于地幔的观点已经被普遍认同，但对其具体形成过程，如地幔源区物质组成、与空间上密切共生的硅酸岩间的关系、碳酸岩岩浆如何演化等问题仍存在广泛争论。项目选择侵入于南秦岭造山带武当地块中的庙垭、杀熊洞正长岩-碳酸岩杂岩体为研究对象，通过详细的矿物学、岩石学、地球化学、微区原位同位素年代学和多元同位素地球化学（包括放射成因同位素、稳定同位素和稀有气体同位素）示踪研究，确定该地区碳酸岩与硅酸岩的活动时代，判断碳酸岩与空间上密切共生的硅酸岩间是否具有成因联系，揭示碳酸岩的成因机制以及碳酸岩岩浆的演化规律，判断碳酸岩源区的地幔属性和碳酸岩岩浆的起源深度，在此基础上示踪大陆地幔源区的组成和特征，并对地幔中碳酸岩交代作用的时间尺度提供制约。揭示碳酸岩杂岩体形成过程与秦岭造山带构造演化间的关系。

Carbonatites are magmatic rocks containing more than 50% modal carbonate minerals and less than 20 wt% SiO2 ultimately derived from the mantle. They have been found on all continents ranging in age from Archean to the present.Though the role of the mantle in carbonatites genesis is well established,There is still no consensus on the issues as to the exact mantle domain(lithospheric mantle or asthenosphere) from which the carbonatitic melts are generated; the relationship between the closely co-existed silicates and carbonatites and the evolutional paths of the carbonatitic magma. We'll carry out mineralogical, petrological and geochemical (including radiogenic isotopes, stable isotopes and noble gas isotopes)investigationson two suites of syenite-carbonatite complexes from Miaoya and Shaxiongdong, which intruded in the southern Qinling orogen.The exact intrusion ages of the syenites and carbonatites will be dated with aim to ensure whether they were formed simutaneously.On the basis of the acquired geochemical data,firm constraints will placed on the petrogenesis of the carbonatites and the associated syenites.The mantle domain(lithospheric mantle or asthenosphere) from which the carbonatitic melts originated will be located.A time scale constraints will also be put on the mantle source and the carbonatitic magma activities based on the Lu-Hf isotopic systematics. Finally,the geochemical dynamic settings and the relationship with the evolution of the Qinliang orogen will be discussed.