GRANITOIDS OF THE GAMOV INTRUSION (southern Primorye), ITS PECULIARITIES AND INDICATOR AND GEODYNAMIC ROLE
N.N. Kruk, V.V. Golozubov, S.A. Kasatkin, S.N. Rudnev, A.A. Vrzosek, K.L. Kuibida, G.M. Vovna
Keywords: Granitoids, geochemistry, geochronology, southern Primorye
Subsection: GEODYNAMICS
Abstract
We studied the geologic position, mineralogy, petrography, chemical composition, and age of granitoids of the Gamov batholith located in the Laoelin-Grodekovo terrane, southern Primorye (Russia). The studies have revealed four intrusive rock phases, from gabbro to leucogranites, in the massif. U-Pb zircon dating of tonalites of phase II and leucogranites of phase IV (254 ± 4 and 259 ± 2 Ma, respectively) shows that the intrusion of granitoids took place in the Late Permian without a significant gap in time. Structural investigations gave evidence for the intrusion in the sublatitudinal-compression setting. Geochemical studies have revealed granitoids of strongly different compositional types in the intrusive massif: gabbroids, quartz diorites and tonalites with characteristics of low-alumina TTG, calc-alkalic granodiorites and I-type granites, and medium-alkali leucogranites. The obtained data, together with the results of previous research into the Permo-Triassic granitoids of southern Primorye, reject the relationship of their formation with the evolution of the Solonker oceanic structures and suggest a more intricate tectonic scenario, which calls for additional study.
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