Abstract:Neoproterozoic igneous rocks on the northwestern margin of the Yangtze block can provide important information about the evolution of Rodinia supercontinent. In this paper, the petrology, geochemistry and isotopic data of the bojite from the Xinmin area of Micang Mountain region are presented. The Xinmin bojite displays low and limited SiO2 content, enrichment of Al and Ca, low K, Ti and P, and medium Mg#, suggesting typical subalkaline, low-K theolite features. The low REE composition, enriched LREE patterns, and positive Eu anomalies (δEu=1.03~2.36) imply the accumulation of plagioclase. The large ion lithophile elements (Rb, Ba, Sr)show enrichment, whereas the high strength elements(Nb, Zr, Hf, Th)are relatively depleted. 87Sr/86Sr=0.703 858, 143Nd/144Nd=0.512 617, and εNd(t)=+3.1. The regional geological and geochemical characteristics reveal that the primary melts were derived from partial melting of depleted mantle rocks and underwent significant crustal contamination in the emplacement process. During this period, the northern margin of the Yangtze block was in a convergence environment and the tectonic environment of the Xinmin bojite was the back arc basin, and hence the Xinmin bojite was the product of the evolution of Rodinia supercontinent in the Neoproterozoic period.