On the problem of methodology of palynological zone determination
At present time palynological analysis is one of the most popular methods of biostratigraphic studies. However, the question about the criteria of classification of stratigraphic units by palynological data raised back in 1970s is still topical. The term ''''palynological zone'''' was first introduced by Muller, a Holland palynologist. In 1968 he singled out typical biostratigraphic zones during his research of Paleogene-Neogene deposits in South America. The main methodological aspects for determining palynological zones in ex-USSR were developed in 1970-80s by E.P. Boytsova, M.V. Oshurkova and others. The criteria and principles of allocating and naming of palynological zones were developed for pre-Quaternary sediments. Later the term ''''palynozone'''' was used in researching Pleistocene and Holocene sediments. In works of modern authors studying Holocene sediments palynological zone are singled out that match by rank to palynological complexes. Some researchers use these terms as synonyms. The small volume of all the Holocene does not allow to determine zones, which correspond to stratigraphic units (suites or stages). As a result, a palynological zone has become not a stratigraphic unit, but a formal one. Palynological zones are allocated in each specific section without tracking their lateral distribution borders. In spite of broad use of the term, there are still no clear, unified rules for determining palynological zones. The differences between the principles of determining palynological zones in sediments of different age contradicts the provisions of the Stratigraphic Code about the unified use of terminology. This prevents a wide range of experts from understanding and application of palynological data. Using different interpretive schemes reduces the capability of regional correlations and detailed dissection of sediments. That is why there is a question about the relevance of using the term palynological zone for the Holocene. The author of the paper finds using this term acceptable only by the rules set in the Stratigraphic Code for determining biostratigraphic units with allowance for the volume of the studied sediments. Palynological zones must be determined on the basis of palynological complexes characterized by the same stages of development of vegetation provided that they can be traced in a series of continuous lateral cuts. In case of no possibility of tracing lateral zone borders at least in one lithofacial district, one should determine palynological complexes.