Nº 12 (2020)

Arsenates and phosphates are rare although challenging minerals of the mixite group. Their general formula is ACu6(TO4)3–x(TO3OH)x(OH)6·3H2O, where A = REE, Ca, Pb, Bi3+, Al; T = As5+, P5+; x = 0–1, hexagonal cell parameters a ≈ 13.5 Å, c ≈ 6 Å, V ≈ 900 Å3, and space group P63/m or P63. There are two subgroups in accordance with chemical composition in T-sites: mixite (T = As) and petersite (T = P). Agardit-(Ce) CeCu6(AsO4)3(OH)6·3H2O from Clara Mine, Schwarzwald, Germany, has been investigated. Unit-cell parameters of agaradite-(Ce) are: a = 13.598(6) Å, c = 5.954(3) Å; V = 953.5(2) Å3; space group P63/m. The structure has been specified and refined to final R = 3.87% for 786 I > 3σ(I). For the first time in the structure of minerals of mixite group hydrogen atoms have been localized and hydrogen bonding has been characterized.

The Karangat Sea is an ancient basin located within the Azov–Black Sea region during the last interglacial epoch (about 130–90 thousand years ago). Its level was 5–10 m higher than the current one, and the salinity was close to the Mediterranean one (about 28–30‰). Traces of its existence can be observed in the natural coastal outcrops of Bulgaria, Eastern Crimea, Taman, the Caucasus, Turkey, and even in the sediments of the western and central parts of the Manych depression, where Karangat waters formed a deep ingressive bay. There is still no common opinion on the number of the Karangat regression stages, its age and rates of development. Until recently, in geography there was no reliable method of absolute dating that would allow determining the age of deposits older than 40 thousand years. Only the introduction of a new approach — the method of optically stimulated luminescence (OSL) — made possible a fairly accurate dating of deposits up to 250–500 thousand years old. In order to clear up the controversial issues in the history of the region, in August 2020, researchers from the Lomonosov Moscow State University and the Institute of Geography (RAS) organized an expedition to the coasts of the Kerch Strait and the southern coast of Crimea.

For the second year in a row, the most prestigious Nobel Prize in physics has been awarded for theoretical research in gravity and cosmology and high-class astronomical observations. In 2019 it was awarded to J.Peebles for theoretical discoveries in physical cosmology and to astronomers M.Mayor and D.Queloz for the discovery of an exoplanet orbiting a solar-type star. In 2020 the Prize is awarded to mathematician R.Penrose “for the discovery that black hole formation is a robust prediction of the general theory of relativity” and to the astronomers R.Genzel and A.Ghez “for the discovery of a super-massive compact object at the center of our galaxy”.

The Nobel Prize in Physiology or Medicine 2020 was awarded jointly to three scientists: Harvey J.Alter, Michael Houghton, and Charles M.Rice “for the discovery of Hepatitis C virus”. This decision highlighted the importance of the discovery and research of a dangerous and widespread human pathogen, which led to the creation of highly effective drugs.