внутриплитные гранитоиды, геохимия, геохронология, петрогенезис, горный алтай, intraplate granitoids, geochemistry, geochronology, petrogenesis, gorny altay, Engineering geology. Rock mechanics. Soil mechanics. Underground construction, TA703-712

The data on geological settings, ages, special features of mineralogy and composition of Sinyushensky Massif granitoids the in north-west part of the Gorny Altay region. The age of the Sinyushensky Massif rocks is 248 ± 0.7 Ma (Ar-Ar dating by biotite). This massif belongs to Permo-Triassic Siberian large igneous province. Sinyushensky Massif granit-leucogranites are drastically different from typical intra-plate A-type granitoids. They correspond to S-type granitoids by mineralogy and petrochemical characteristics, and are characterised by the increased fluorine and LILE concentrations. Nd isotopic composition corresponds to that of the metasedimentary rocks of the north-west Altay’s upper crust. The formation of Sinyushensky Massif granitoids melts was the consequence of continental crust rocks melting. The enrichment by LILE and Ce-group REE associates with the influence of deep fluids caused selective melting of mica and accessory minerals.