The article presents geological, mineralogical, geochemical, and isotope-geochemical studies of charnockites from the Tatarinovsky massif located in the northern part of the Baikal uplift of the Siberian craton basement. The charnockites, dated to 1.85 Ga, are part of the South Siberian post-collisional magmatic belt. They form a series of small massifs within the Davan tectonic zone but have not undergone dynamometamorphism, mylonitization, or metasomatism, suggesting they formed after the zone's structural development. The charnockites' formation coincides with the youngest formations in the North Baikal volcanoplutonic belt (1.85–1.84 Ga). The charnockites exhibit two facies varieties: coarse-grained and medium-fine-grained porphyritic, with a gradual transition between them. Mineral composition, specifically the presence of orthopyroxene, classifies them as charnockites. The chemical composition of the charnockites corresponds to monzonite and syenite, with fine-grained porphyry granitoids being granosyenite. All studied charnockites are close to alkaline and calc-alkaline, metalumin (ASI=0.83–0.97), ferrous (FeO*/(FeO*+MgO)=0.86–0.89) granites, with high concentrations of Nb, Y, Zr, and Ba, and low concentrations of Sr. Their geochemical characteristics correspond to A-type granites, with negative εNd(t) values of −1.4 to −3.5 and model age TNd DM of 2.4–2.5 Ga. The initial crystallization temperatures of the charnockite melts were estimated to be 890–960°C (zircon saturation temperature), and the melts crystallized in hypabyssal conditions at pressures of 2.2–2.9 GPa, with low or moderate oxygen fugacity. Mineralogical, geochemical, and isotope-geochemical data suggest that the charnockites may have formed from the melting of mafic rocks from the lower crust (gabbroids and ferrodiorites), which are products of differentiation of tholeiitic mantle magmas intruded into the base of the continental crust. High Ba concentrations and positive Eu anomalies in the REE distribution spectra of coarse-grained charnockites indicate partial melting of crustal mafic sources. Fine-grained porphyry charnockites, with higher silica contents and lower Ba and Zr contents, as well as negative Eu anomalies in the REE distribution spectra, are products of fractional crystallization of the charnockite melt. The geodynamic setting for the formation of the Tatarinovsky charnockites is considered as post-cThe article presents geological, mineralogical, geochemical, and isotope-geochemical studies of charnockites from the Tatarinovsky massif located in the northern part of the Baikal uplift of the Siberian craton basement. The charnockites, dated to 1.85 Ga, are part of the South Siberian post-collisional magmatic belt. They form a series of small massifs within the Davan tectonic zone but have not undergone dynamometamorphism, mylonitization, or metasomatism, suggesting they formed after the zone's structural development. The charnockites' formation coincides with the youngest formations in the North Baikal volcanoplutonic belt (1.85–1.84 Ga). The charnockites exhibit two facies varieties: coarse-grained and medium-fine-grained porphyritic, with a gradual transition between them. Mineral composition, specifically the presence of orthopyroxene, classifies them as charnockites. The chemical composition of the charnockites corresponds to monzonite and syenite, with fine-grained porphyry granitoids being granosyenite. All studied charnockites are close to alkaline and calc-alkaline, metalumin (ASI=0.83–0.97), ferrous (FeO*/(FeO*+MgO)=0.86–0.89) granites, with high concentrations of Nb, Y, Zr, and Ba, and low concentrations of Sr. Their geochemical characteristics correspond to A-type granites, with negative εNd(t) values of −1.4 to −3.5 and model age TNd DM of 2.4–2.5 Ga. The initial crystallization temperatures of the charnockite melts were estimated to be 890–960°C (zircon saturation temperature), and the melts crystallized in hypabyssal conditions at pressures of 2.2–2.9 GPa, with low or moderate oxygen fugacity. Mineralogical, geochemical, and isotope-geochemical data suggest that the charnockites may have formed from the melting of mafic rocks from the lower crust (gabbroids and ferrodiorites), which are products of differentiation of tholeiitic mantle magmas intruded into the base of the continental crust. High Ba concentrations and positive Eu anomalies in the REE distribution spectra of coarse-grained charnockites indicate partial melting of crustal mafic sources. Fine-grained porphyry charnockites, with higher silica contents and lower Ba and Zr contents, as well as negative Eu anomalies in the REE distribution spectra, are products of fractional crystallization of the charnockite melt. The geodynamic setting for the formation of the Tatarinovsky charnockites is considered as post-c