Nº 6 (2023)

The history of the formation, evolution, and disappearance of the inland giant Paratethys sea is considered from the time of its formation in the middle of the Cenozoic (34 million years ago) to the final separation of its waters into the Black and Caspian seas at the end of the Miocene epoch (5.6 Ma). The history of Paratethys and the organisms inhabiting it was mainly determined by its connections with oceans. Their expansion led to the uprising of the Paratethys water level to that of the World Ocean, and subsequently, its colonization by marine organisms. The drying of the straits turned Paratethys into a huge lake. The level and salinity of its waters depended on the ratio of river runoff and evaporation: with a positive water balance, the basin began to expand and desalinate, with a negative one, it regressed, saline bays and lagoons appeared in it. Obviuosly, marine biota had died in such conditions and only some organisms were able to tolerate abrupt changes in salinity, ion and oxygen regimes promoted development of specific brackish-water groups of fauna. The existing ideas about the paleogeography of this basin well reflect the intervals of high sea water levels, but do not address the results of rather signifi cant drops in sea level during its trapped episodes. Until recently, paleogeography had no appropriate methods to reconstruct such stages. Only now, with the development of seismostratigraphy, it has become possible to assess the scale and spatial patterns of paleogeographic changes with signifi cant basin reductions during regression periods.

The article presents the results of the studies on Mongolian volcanic structures: data on toponymy and interpretation of images, visual assessment of objects, research on morphometric indicators, cartographic operations, and preparation of thematic illustrations. We consider the most representative sites with volcanic landforms and various volcanic edifi ces of diff erent degrees of preservation and present a list of the 25 most illustrative areas from more than 160 volcanic structures located in seven regions of Mongolia. The fi rst version of the catalog of objects with important information for the geotourism development has been created. Volcanoes, volcanic landscapes, and outcrops of igneous rocks of Mongolia are essential objects for science and education, and may be of interest for thematic tourism.

One of the most chemical and structural complicated mineral, zircon-silicate eudialyte, was discovered 200 years ago, however it is still an object of studies. This article reports about the Special Issue of the journal Minerals, which includes 13 articles on eudialyte crystal chemistry, mineralogy, and petrography. Moreover, recently the eudialyte group has been completed by a new mineral, the 31st member, selsurtite. Very substantial reports consider the eudialyte synthesis and new methods of mineral decomposition for extraction of some useful elements from its structure.

The nature of knowledge, elucidation of the relationship between the essence of phenomena and our sensory perception, science, and art are considered on an example of water. Water makes up most of the Earth’s surface, and its percentage in the human body is high. It pleases the eye, serves as a subject of study for various sciences, and is a source of creative inspiration.