СТРАТИГРАФІЧНА СХЕМА НЕОГЕНОВИХ ВІДКЛАДІВ КРИМСЬКОГО ПІВОСТРОВА

Abstract

A new modernized stratigraphic scheme of the Crimean Peninsula is introduced in this study. The scheme is supported by new and previously published data on the distribution of lithological types of the Neogene deposits and their detailed biostratigraphic analysis. This stratigraphic scheme is the final which was created on results of personal researches (2009-2015) on the topic “Modernization of local stratigraphic schemes of the Neogene deposits of the Southern Ukraine”. As a result, local stratigraphic units that unite the Neogene deposits of the Northern Black Sea region, the Crimean and the Kerch Peninsula were allocated; a unified stratigraphic model of the Neogene of the Southern Ukraine was created and has been presented in corresponding stratigraphic schemes (see also Vernyhorova, 2014, 2015b). The Neogene deposits are presented on the whole Crimean Peninsula. Marine deposits consist from all the Neogene sequence. Continental deposits were accumulated in the late Maeotian, the Pontian, the Kimmerian and the Kuialnykian times. During the Neogene time, the most part of the Crimean Peninsula and the Southern-Eastern part of the Nothern Black Sea region (the area between Melitopol city and the Crimean mountains) were a single marine basin. It was called the Tauride Strait by V.P. Kolesnikov (Stratigraphy USSR, 1940). This Strait had similar lithofacies and paleontological peculiarities. It was the most impressively in the Chokrakian-Kuialnykian time. However, the Eastern part of the Crimean Peninsula and the Western part of the Kerch Peninsula were the Western part of the Indol Gulf (by Muratov, 1960) in the Neogene time. This area had also special environmental conditions and facies which were different from the surrounding areas. It was the most impressively in the late Sarmatian-Kuialnykian time. Such peculiarities were described in numerous publications about the Neogene Basin of the Crimean Peninsula (Stratigraphy USSR, 1940; Muratov, 1960; Molyavko, 1960; Geology USSR, 1969; Belokrys, 1976; Chekunov et al., 1976) and also were investigated by author of this article. There are currently three stratigraphic schemes (1993, 1995, 1996) and the stratigraphic basis of the State geological maps (2004, 2006-2008) are utilised for stratigraphic subdivision of the Neogene deposits of the Crimean Peninsula. These schemes (1993, 1995) are mainly based on biostratigraphic (molluscs, foraminifers, ostracods) studies. Therefore local stratigraphic subdivisions utilized in these schemes (according to the Stratigraphic Code of Ukraine, 1997, 2012) are essentially biostratigraphic units, namely «beds with fauna». The stratigraphic schemes (1996) and Legends of the State geological maps (2004, 2006-2008) consists of the combination of biostratigraphic and lithostratigraphic subdivisions which are often allocated simultaneously in the coeval deposits. These facts impedes using these stratigraphic schemes as a basis for developing of legends for large-scale and medium-scale geological maps. In addition, the Neogene deposits of the Crimean Peninsula was characterized separately from the coeval deposits of the Northern Black Sea and the Kerch Peninsula in stratigraphical schemes (1993, 1995, 1996) and the State geological maps (2004, 2006-2008). As result, a large number of coeval local stratigraphic subdivisions, which have similar lithological, paleontological characteristics and also have dif ferent names, was allocated in these border areas. The scheme (as other new stratigraphical schemes of the Southern Ukraine – see Vernyhorova, 2014, 2015b) includes regional stratigraphic units – «horizons» that are subordinate to regional stages. Horizons are characterized by mollusc assemblages or other paleontological groups which should be typical for different coeval facies in the greatest number structural-facies zones of the Southern Ukraine. During the creation of this scheme, the volume of local stratigraphic subdivisions in previous stratigraphic schemes (1993, 1995, 1996) and the State geological map (2004, 2006-2008) has been revised; their stratigraphic status and names have been emended; controversial issues of stratigraphic subdivision of the Neogene deposits are discussed in the text; stratigraphic conclusions had substantiated by actual data about litho- and biostratigraphical features of the Neogene deposits of the study area.