Abstract:Based on geological investigation, this paper studies the wholerock element geochemistry, zircon UPb geochronology, SmNd isotopic compositions and in situ zircon Hf isotope of the southern Dayishan biotite monzogranitic batholith in Guiyang City, Hunan Province. With reference to previous research, we discuss petrochemical property, forming age, material sources, as well as petrogenesis of the southern Dayishan granitic batholith. LAICPMS zircon UPb isotopic analyses show that the southern Dayishan granite was emplaced during the Early Yanshanian, with a weighted mean n(206Pb)/n(238U) age of 153.4 ± 1.1Ma (MSWD = 0.30, 2σ, N = 21). Two inherited zircon cores yield n(207Pb)/n(206Pb) ages of 2449 Ma and 2498 Ma, respectively. The southern Dayishan granite is characterized by high silicon, high potassium, metaluminous to weak peraluminous as well as rich in Light Rare Earth Elements (LREEs) and some Large Ion Lithophile elements (LILEs, Rb, K), while depleted in Heavy Rare Earth Elements (HREEs) and some High FieldStrength elements (HFSE, Nb, Ta, Ti) and Ba, Sr and P. It exhibits characteristics of Zr+Nb+Ce+Y>350*10-6 and 10000*Ga/Al>2.6, being similar to Atype granites. SmNd isotopic study shows εNd(t) values ranging from -6.94 to -5.19 and twostage model ages of Nd isotope (TDM2) within the range of 1.37 to 1.51 Ga. In situ zircon Hf isotope yields εHf(t) ranging from -9.35 to -1.16 and TDM2 from 1.28 to 1.79 Ga. Two Paleoproterozoic inherited zircon cores yield εHf(t) of -6.82 and 1.48, respectively. The petrochemistry and isotopic characteristics indicate that the southern Dayishan granite was mainly derived from melting of Paleoproterozoic crustal metagreywackes, and maybe contaminated by a small amount of mantle material. During Early Yanshanian, the rollback of paleoPacific Plate resulted in tectonic extension and thinning of the continental lithosphere of the study area. The underplating of mantlederived magma in response to upwelling of the asthenosphere induced partial melting of the Palaeoproterozoic lower crust and produced granitic magma. The magma then invaded along deep faults and formed the southern Dayishan granitic batholith (Taipingshan Body).