Chance Gold Deposit is an important medium-scale gold deposit in the Laoling gold polymetallic metallogenic belt in southern Jilin Province.The ore bodies in the district are stratiform,in veins and saddle form,and      mainly occur near the contact zone between Zhenzhumen Formation and Huashan Formation of Laoling Group,as well as in the altered diorite.Toudaogou granite intrudes into the marble of Zhenzhumen Formation and is distributed in the southeast side of the district,occurring as a small stock and    mainly composed of porphyritic biotite granite.The zircon U-Pb dating shows the weighted mean zircon ages of Toudaogou granite are 120 Ma±1 Ma,indicating that the crystallization epoch is the early Cretaceous.The results of whole rock geochemical analysis show that Toudaogou granite are high in silicon content,and  low   in MgO and CaO content.The samples are relatively enriched in large ion lithophile elements such as K,Ba and Rb and active incompatible elements such as Th and U and are depleted in high field strength elements such as Nb,Ta,P and Ti.The REE distribution curve normalized to chondrite shows a right-declined type and weakly negative Eu anomaly,indicating the residue of a small amount of plagioclase in the source area.The rock belongs to a metaluminous granite transiting from high-K calc-alkaline to shoshonite series with I-type granite features,so it is inferred that Toudaogou granite probably originated from partial melting of thickened lower crust representing late Mesozoic magmatism in Southern Jilin Province,formed in the post collision diagenesis tectonic setting representing the transition from compression to extension after orogeny related to the subduction of the Paleo-Pacific plate,and occurred in the same tectonic setting with the gold mineralization event at about 120 Ma in southern Jilin Province.