On the Allocation of Regional Geological Monuments of the Main Devonian Field

Abstract

—Using the example of two particularly valuable geological objects of the Main Devonian Field (Ilmen glint and the valley of the Velikaya River in the area of the Vybuty rapids), the features of the allocation and protection of geological monuments of regional significance are considered. Ilmen glint is a complex (stratigraphic, paleontological, ore-litho-petrological, hydrogeological) geological monument of regional significance. The authors substantiate the paleogeographic value of the object, which consists in the possibility of studying various ecological complexes of the macrofauna of the Middle Frasnian Sea, reflecting both regressive and transgressive stages of its development. Also, for the Ilmen glint are recommended two new criteria: a historical criterion (reflection of information about a geological object in the classical geological literature) and (for the first time) the introduction of a new historical and geographical criterion (the relationship of geological and geographical features with the history of settlement and development of the region). As a unique geological object, Ilmen glint has been studied by outstanding Russian and foreign researchers. The sections of the glint and the near-glint region are stratotypic for a number of sub-regional and local subdivisions of the Middle Frasnian of the Main Devonian Field. The features of the geological structure (close occurrence to the surface of carbonate rocks of the Upper Devonian), proximity to Novgorod and convenient communication with it by water influenced the fact that this area became one of the areas of ancient mining back in the days of Veliky Novgorod. Due to the location at the crossroads of important roads, the surroundings of glint often turned out to be the scene of important historical events, so in the village of Korostyn, located at the western tip of glint, the famous Korostyn Peace was concluded. The Vybuty Rapids tract is not a protected area, although it also has a clear scientific value from the paleogeographic (interesting complexes of ichnofossils are observed in the outcrop and extremely valuable in the reconstruction of paleogeographic conditions of the hardground facies) and historical and geographical points of view (a large ford was the strategic place in the Middle Ages for Pskov). The article considers the influence of natural and anthropogenic hazards on the condition of the described geological objects. In the described unique outcrops, there is an active manifestation of landslide processes and weathering processes. At the same time, the terrain features (the presence of local plicative and disjunctive structures that contribute to the formation of zones of increased fracturing) are aggravated by the active traffic load in the areas adjacent to the coastal cliffs.