The U–Pb (LA-ICP-MS) dating of detrital zircons from the Upper Cretaceous Derevyannye Gory Formation in the Novaya Sibir Island revealed that tuffites and tuffaceous sandstones contain zircons widely ranging in age from Archean to Upper Cretaceous. The weighted average age of the youngest zircon population is 88 ± 1.0 Ma, which constrains the lower age limit for sedimentation of the Derevyannye Gory Formation to the Coniacian. The clastic material was transported from the southwest and south to the north and northeast. The main source areas for the Upper Cretaceous sedimentary basin in the Novaya Sibir Island were the Upper Jurassic–Neocomian terrigenous sequences of the New Siberian–Chukotka fold area, lithotectonic complexes of the South Anyui suture, as well as the northern part of the Verkhoyansk–Kolyma fold area, and post-orogenic Aptian–Albian volcanic and plutonic rocks from the Lyakhov Islands and Svyatoi Nos Cape. Triassic terrigenous rocks of the northern Verkhoyansk region could serve as additional sources of clastics. It is also possible that the clastic material was partially supplied from the western Anjou Islands as a result of erosion of the Aptian–Lower Albian volcaniclastic–siliciclastic rocks. The Late Cretaceous zircon population is related to the Late Cretaceous explosive acid volcanism in the eastern Arctic region.
The K–Ar isotope age and petrological–geochemical data were obtained for the first time on igneous rocks from a core recovered from previously drilled wells on the Sakhalin shelf. Based on these data, the igneous rocks were compared to the rocks of the Anivskiy, Orlovskiy, Lamanonskiy, and Chekhovskiy volcanic complexes. The isotopic ages obtained on rocks from the Lesogorskiy Complex of hypabyssal small intrusions exposed on the western coast of Sakhalin Island allowed tighter constraints to be placed on the timing of its formation (8.9–16.2 Ma).