Research On The Petrogenesis And Tectonic For Late Carboniferous Intrusive Rocks In Northeastern East Ujim Qin Banner,Inner Mongolia

Late Paleozoic granitoids are widely developed in northeastern East Ujimqin Banner.SHRIMP U-Pb zircon age,XRF and ICP-MS are reported for geochemistry and geochronology of the granitoids thereto study combining previous understanding and group's results,and then discuss forming age,geochemical characteristics,Petrogenesis and tectonic setting of Late Paleozoic intrusive rocks in northeastern East Ujimqin BannerZircon U-Pb dating of the four spotted magmatogenic diorite-granite from the region was performed,yielding the 302.5±3.3Ma,320.3±3.7Ma,307.7±5.1Ma and 299.2±5.3Ma,suggesting the crystallization age and that invading in the Late CarboniferousGeochemical characteristics suggest that main rock type is monzonitic granite,syenogranite,granite-porphyry and granodiorite.The content of SiO2,Al2O3 and Alk are as follows:65.65?77.61%,12.10%?15.76%and 8?9.62%.They indicate that the granite has metaluminous potassium,with high K cale-alkaline-shoshonite series.Large ion lithophile elements(LILE)of intrusive rocks in working area are enriched,but Zr and Yb obvious depletions,showing weak-medium negative Eu anomaly.The granite is mainly product of I-type granite and less A-type granite,it formed in the developmental stage of post-collisional.Based on the study of diagrams,the author consider that granite in northeastern East Ujimqin Banner are derived from lower crust,and contaminated by the mantle-derived magma.In the rise process,some oldest crustal material go into the magma.Then,it generate the granite by crystal fractionation.