New Data on the Upper Quaternary Stratigraphy of the North Caspian Seaстатья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 11 мая 2021 г.
Аннотация:The sedimentary sequence over 80 m thick recovered by drilling through the Shirotnaya struc-ture in the northern Caspian Sea may be considered as the upper Pleistocene stratotype sec-tion for the entire basin. It represents a continuous succession of the Upper Khazarian, Atelian, Khvalynian, Mangyshlakian, and Novocaspian stratigraphic horizons composed of marine and terrestrial facies with boundaries between them readily distinguishable in seismoacoustic records. Each of these units is characterized by different molluscan assem-blages with guide and characteristic species. The composition of these assemblages differs from that in their coeval counterparts in the onshore Caspian sections by the presence of deepwater species. The stratigraphic subhorizons contain molluscan fossils,which represent an element of faunal assemblages characteristic of horizons and exhibit features in common with them. The section of Upper Quaternary sediments recovered by offshore boreholes inclu-des stratigraphic units still unknown in onshore sections: the Girkanian Subhorizon and lower part of the Lower Khvalynian Subhorizon. This allows the geological history of the Caspian basin in the late Quaternary Period to be reconstructed in more detail. The radio-carbon investigations revealed that sedimentation of the Novocaspian Horizon commenced about 8, Mangyshlakian Horizon about 11, Upper Khvalynian Subhorizon, and about 20 ka, and Lower Khvalynian Subhorizon prior to 30 ka ago.