- Rostov Oblast (Wikipedia)
Rostov Oblast (Russian: Росто́вская о́бласть, romanized: Rostovskaya oblast’, IPA: [rɐˈstofskəjə ˈobləsʲtʲ]) is a federal subject of Russia (an oblast), located in the Southern Federal District. The oblast has an area of 100,967 square kilometers (38,984 sq mi) and a population of 4,200,729 (2021 Census), making it the sixth most populous federal subject in Russia. Its administrative center is the city of Rostov-on-Don, which also became the administrative center of the Southern Federal District in 2002.
- Basalt (Wikipedia)
Basalt (UK: /ˈbæsɔːlt, -əlt/; US: /bəˈsɔːlt, ˈbeɪsɔːlt/) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90% of all volcanic rock on Earth is basalt. Rapid-cooling, fine-grained basalt is chemically equivalent to slow-cooling, coarse-grained gabbro. The eruption of basalt lava is observed by geologists at about 20 volcanoes per year. Basalt is also an important rock type on other planetary bodies in the Solar System. For example, the bulk of the plains of Venus, which cover ~80% of the surface, are basaltic; the lunar maria are plains of flood-basaltic lava flows; and basalt is a common rock on the surface of Mars.