北淮阳带东段前中生代岩浆作用和变质作用的岩石学及年代学研究

已有研究表明，北秦岭古生代造山带及商丹缝合带向东延伸到信阳、乃至商城地区，但至大别山之后，如何衔接，一直是前人未曾系统深入研究并涉及到北淮阳带华南与华北板块之间汇聚过程厘定的关键科学问题。申请者等最近在北淮阳带东段发现的早古生代花岗岩和石炭纪变质作用、已报道的北淮阳带石炭纪地层中含有扬子属性的晚奥陶世-早志留世古生物化石的灰岩砾石及变质复理石和中生代盆地沉积物的古生代碎屑锆石年龄记录以及华北东南缘深源包体的古生代变质改造等方面的线索和证据为北秦岭及商丹缝合带的东延研究提供了良好契机。为此，本项目拟根据已有线索，对北淮阳带东段及相邻地区进行详细的野外调查，重点查明古生代花岗岩以及庐镇关杂岩和相关岩石的组成及其分布；开展前中生代岩浆作用和变质作用的岩石地球化学和年代学研究，查明北淮阳带东段古生代变质演化过程及P-T-t轨迹，揭示大别山三叠纪大陆碰撞之前南、北板块之间的古缝合线位置和汇聚过程。

Previous researches suggested that the northern Qinling Paleozoic orogen and Shang-Dan Ocean most likely occurred from the Qinling, eastwardly to Xinyang and even to Shangcheng areas. However, how to build the link between the Qinling and Dabie orogens, which will be involved in defining the convergent processes between the North China Block and the South China Block, remains to be further explored in the eastern Beihuaiyang zone of the Dabie orogen. Recently, the applicants found the early Paleozoic granites and Carboniferous metamorphism in the eastern segment of the Beihuaiyang zone. In addition, the limestone conglomerate from the Carboniferous sedimentary strata contains the late Ordovicianearly Silurian marine fossils with the Yangze affinity, and there are a lot of the early Paleozoic detrital zircon age-records from the meta-flysch and Mesozoic basin sediments. Furthermore, there are some important clues and evidences related to the Paleozoic magmatism and metamorphic modification from the deep-seated xenoliths in the southeastern margin of the North China Block. These new findings and clues provide an excellent opportunity to study the eastward extension of the northern Qinling orogen and Shang-Dan suture zone in the eastern Beihuaiyan zone and adjacent region. Therefore, this project will carry out the detailed field geological investigations on the Beihuaiyang zone and adjacent areas in order to clarify the rock compositions of the Paleozoic granites, Luzhenguan complex and related rocks, and their distributions. By a combined study of petrogeochemistry and geochronology of the Pre-Mesozoic magmatism and metamorphism, the eastward extension of the northern Qinling orogen and Shang-Dan suture zone in the Dabie orogen and adjacent areas will be further investigated. Based on the obtained results and published data, we will reconstruct the Paleozoic metamorphic evolution and P-T-t path of the eastern Beihuaiyang zone involved in the Paleozoic convergent processes, and the locality of suture zone before the Triassic Dabie collision between the North China Block and the South China Block.