Zircon U-Pb Geochronology, Geochemistry and Geological Significance of Granites in Huren Mutumen Woblezhuo Area, Inner Mongolia

Late Carboniferous granites are widely exposed in the Huren mutumen Woblezhuo area, Sonid Left Banner, Inner Mongolia. LA-MC-ICPMS U-Pb dating of zircons from magmatic rocks shows that the intrusion ages of biotite-bearing monzonitic granites are(317.0 ± 1.6) Ma and (313.5 ± 1.5) Ma in the study area。This suggests that the rocks studied in this paper were formed in the Bashkirian-Moscovian(Pennsylvanian). By the geochemical analysis, the samples are peraluminous high-K calc alkaline series rocks. In the chondrite-normalized REE diagrams, it exhibits ΣREE content ranging from 110.77 × 10^-6 to 147.29 × 10^-6, enrichment in LILE and LREE, depletion in HREE and HFSE. In the primary mantle-normalized trace element fractional diagrams, it shows that the major lithophile elements such as Rb, Th and U are relatively enriched, while the high field strength elements such as Nb, Ta, HF and Zr are slightly enriched, and Ba, Sr and Ti are relatively depleted. the paleo-asian ocean closed before the Late Carboniferous epoch, and the biotite-bearing monzonitic granites developed in a post-orogenic extensional regime in the study area.