BalticaBaltica is a paleocontinent that formed in the Paleoproterozoic and now constitutes northwestern Eurasia, or Europe north of the Trans-European Suture Zone and west of the Ural Mountains. The thick core of Baltica, the East European Craton, is more than three billion years old and formed part of the Rodinia supercontinent at 1 (). Baltica formed at 2.0–1.7 Ga by the collision of three Archaean-Proterozoic continental blocks: Fennoscandia (including the exposed Baltic Shield), Sarmatia (Ukrainian Shield and Voronezh Massif), and Volgo-Uralia (covered by younger deposits).
ReindeerThe reindeer or caribou (Rangifer tarandus) is a species of deer with circumpolar distribution, native to Arctic, subarctic, tundra, boreal, and mountainous regions of Northern Europe, Siberia, and North America. This includes both sedentary and migratory populations. It is the only representative of the genus Rangifer. Herd size varies greatly in different geographic regions. More recent studies suggest the splitting of reindeer and caribou into six distinct species over their range.
Ice coreAn ice core is a core sample that is typically removed from an ice sheet or a high mountain glacier. Since the ice forms from the incremental buildup of annual layers of snow, lower layers are older than upper ones, and an ice core contains ice formed over a range of years. Cores are drilled with hand augers (for shallow holes) or powered drills; they can reach depths of over two miles (3.2 km), and contain ice up to 800,000 years old. The physical properties of the ice and of material trapped in it can be used to reconstruct the climate over the age range of the core.
Ural MountainsThe Ural Mountains (ˈjʊərəl ; Уральские горы) or simply the Urals, is a mountain range in Eurasia that runs north-south mostly through Russia, from the coast of the Arctic Ocean to the river Ural and northwestern Kazakhstan. The mountain range forms part of the conventional boundary between the continents of Europe and Asia. Vaygach Island and the islands of Novaya Zemlya form a further continuation of the chain to the north into the Arctic Ocean. The average altitudes of the Urals are around , the highest point being Mount Narodnaya, which reaches a height of .
Nuclear weapons testingNuclear weapons tests are experiments carried out to determine the performance, yield, and effects of nuclear weapons. Testing nuclear weapons offers practical information about how the weapons function, how detonations are affected by different conditions, and how personnel, structures, and equipment are affected when subjected to nuclear explosions. However, nuclear testing has often been used as an indicator of scientific and military strength.
ArcticThe Arctic (ˈɑrtɪk or ˈɑrktɪk) is a polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenland), northern Finland (Northern Ostrobothnia, Kainuu and Lappi), Iceland, northern Norway (Nordland, Troms, Finnmark, Svalbard and Jan Mayen), Russia (Murmansk, Siberia, Nenets Okrug, Novaya Zemlya), northernmost Sweden (Västerbotten, Norrbotten and Lappland) and the United States (Alaska).
