Lithological-magneto-palynological characteristics of the Upper Miocene, Pliocene and Gelasian deposits of the Cenozoic reference section of the Dnieper-Donetsk depression (Ukraine)

Abstract

Well 11 is located near the village of Velika Lanna, Krasnograd District, Kharkiv Region, and at the current stage of research is the most representative section of the continental Upper Cenozoic deposits of the Dnieper-Donets depression. For the first time, a comprehensive description of the Upper Miocene, Pliocene, and Pleistocene deposits obtained from the results of paleopedological, palynological, and paleomagnetic studies is presented for the research region. Characteristic features of 13 climatolites (pedocomplexes and intersoil clays) including five upper Miocene, three lower Pliocene, two upper Pliocene and two climatolites correlated with the Gelasian of the International Stratigraphic Scale were determined. According to the results of miner- alogical studies, three mineralogical strata such as montmorillonite-kaolinite, hydromica-montmorillonite, and hydromica were traced for the deposits of the section. The mineralogical boundaries are confined to the levels of the Salgir–Liubimivka and Siversk–Beregove climatoliths. The spore-pollen complexes of all studied deposits are described. It was established that the complexes characterizing each studied climatolith differ in taxonomic composition, the ratio of the pollen of the main groups of plants, and the presence of characteristic taxa. Changes in the composition of spore-pollen spectra characterizing all soils of pedocomplexes as well as intersoil clays and embryonic soils formed during short-term warming at the time of the cool stages of the Miocene, Pliocene, and Gelasian periods were traced. The described spore-pollen complexes and spectra were compared with those from the deposits of the same age in adjacent regions, which allowed identifying the general and regional features of the compared complexes. A detailed record of changes in the geomagnetic field during the formation of the Upper Miocene-Pleistocene deposits was obtained, which enables to construct a paleomagnetic section reflecting the areas with normal, reverse and anomalous polarity. According to the nature of distribution of such areas, the section is tied to the Cox scale. All these materials allowed carrying out the stratigraphic dissection of the Miocene-Gelasian deposits of the studied section, as well as to substantiate the feasibility of defining it as a reference for the Miocene-Pleistocene deposits of the Dnieper-Donets depression.