南秦岭地体北缘岩浆作用与地壳演化

In this proposal, basement rocks of the Douling Group, Neoproterozoic dioritic rocks, Paleozoic granitoids and low-grade metamorphosed sedimentary cover rocks exposed along the northern margin of the South Qiling terrain are chosen for study. On the basis chiefly of precise zircon ages and isotope geochemistic data,we shall place contraints on formation and metamorphic history of basement rocks, emplacement time and genesis of Neoproterozoic and Paleozoic magmatic rocks, and material sources and record of magmatism in detrital zircons of sedimentary cover rocks. A geochronological framge of the magmatic activities in the northern margin of South Qinling and their tectonic settings since the Neoproterozoic time can be constituted for reconstruction of the crustal evolution in this terrain. In the run of the study,three key issues about the crustal evolution of South Qinling will be emphasized, i.e., magmatic events and geological implication recorded in basement rocks, the Neoproterozoic magmatism and its relationship with the superconitinent, and genetic relationship between the Paleozoic magmatism and the formation and evolution of the North Qinling orogen. A comparison study will be done on magmatic rocks forming in different periods in both the North and South Qinling terrains for further understanding crustal evolution of the basements since the Neoproterozoic time in the Qinling orogenic belt.

申请项目选择在鄂-豫-陕交界地区南秦岭地体北缘出露的基底岩石单元陡岭岩群、新元古代闪长岩类岩体、古生代花岗岩类岩体、低级变质沉积盖层刘岭岩群为主要研究对象，以精细的锆石年代学和同位素地球化学示踪为研究基础和突破口，准确厘定基底岩石形成和变质时代、新元古代和古生代岩浆岩形成时代和成因、沉积盖层物质来源和记录的岩浆作用信息。建立南秦岭地体北缘新元古代以来岩浆事件的年代学框架及其成因构造背景，恢复其地壳演化历史，突出探讨南秦岭地体前寒武纪基底岩浆事件和性质、新元古代岩浆作用与超大陆演化的关系、古生代岩浆作用与北秦岭造山带形成和演化的成因联系。重点通过对比研究南、北秦岭地体内不同期次岩浆作用事件，深入认识研究区元古代-古生代地壳演化，为细化秦岭造山带新元古代-早中生代构造演化过程提供重要信息。

在项目执行期间，选择南秦岭地体北缘出露的基底岩石单元陡岭岩群、新元古代闪长岩类岩体、多期次花岗岩类岩体、低级变质沉积盖层刘岭岩群为主要研究对象，通过大量的锆石年代学和同位素地球化学组成等观察数据，厘定了基底岩石形成和变质时代、沉积盖层物质来源、多期次岩浆作用时代和地球化学组成特征，探讨了南秦岭地体北缘地壳演化和新元古代以来岩浆事件的构造背景，特别是前寒武纪基底岩浆事件和性质、新元古代岩浆作用与超大陆演化的关系。发表与项目的研究内容相关的学术论文9篇，其中7篇SCI论文，培养数位硕士和博士研究生，两位年轻科研人员晋升为副高级职称，有效地充实了造山带地壳演化研究团队的力量。