Volcanic Rocks and Granitoids from Cape Svyatoy Nos (Eastern Arctic): Their Age, Composition, and Paleotectonic Reconstructions

For the first time, geochemical and geochronological (U–Pb SIMS, zircon) data are obtained for volcanic rocks and tuffs of the volcanic–sedimentary sequence and for granitoids intruding them in the Cape Svyatoy Nos area (eastern Arctic). The concordant U–Pb age of basalts is 146 ± 2. The ages of granitoids are 114 ± 1, 112 ± 1, and 114 ± 2 Ma. These ages correspond to the Late Jurassic (Tithonian) and the Aptian–Albian boundary. The section structure and the geochemical characteristics of the volcanic rocks and tuffs, as well as their similarities with the Mariana arc volcanics, indicate their formation in the settings of an intraoceanic subduction zone. The data obtained allow us to suggest that the volcanogenic–sedimentary rocks of Cape Svyatoy Nos represent a continuation of the Kul’pol’nei oceanic arc, which marked the northeastern convergent boundary between the Siberian continent and the South Anyui Basin in the Late Jurassic. In terms of their petrographic composition and petrogeochemical characteristics, the Aptian–Albian granitoids correspond to type I granites. The time of their intrusion coincides with the extension after the ending of the collision between the Siberian continent and the Chukotka–Arctic Alaska microplate as a result of the South Anyui Basin consumption.