Intrusive Complexes of the North-eastern Part of the Zhezkazgan Depression

The article presents the results of studying three intrusive complexes in the northeastern part of the Zhezkazgan Depression: the Early Devonian Karamen gabbro-diorite-granodiorite-granite complex; the Middle Devonian Terekty granite-leucogranite complex, with granites of moderate alkalinity; and the Middle-Late Devonian Kokkuduktyube sub-alkaline leucogranites. It is noted that the features of the textural and structural characteristics of the rocks of the intrusive complexes are also manifested in their chemical composition. The chemical composition was studied based on the results of silicate analyses using the sum of K₂O+Na₂O-SiO₂ and the Na₂O/K₂O-SiO₂ ratio. This made it possible to classify them into specific types. As a result of field and laboratory studies, including the processing of silicate analyses, the classification of igneous rocks in the region was refined. The article provides a brief description of vein and dike bodies; the mineral composition of granodiorites, granites, leucogranites, moderately alkaline and biotite-hornblende granites, as well as their magnetic susceptibility and density values.