Taman loess-paleosol sequence: structure, age, genesis

Loess deposits are widely spread all over Eastern Europe, extending as far south as the the Sea of Azov andthe northern Black Sea. For many decades these regions have been noted for series of key sections.However, despite prolonged investigations, a lack of absolute dating and detailed lithological data has leftmany unresolved problems in the correlation of the regional stratigraphic schemes. In this study, integratedstudies were undertaken on the loess-paleosol sequence exposed on the northern coast of the TamanPeninsula, separating the Sea of Azov from the Black Sea. The southern coast of the Sea of Azov, in thenorth of the Taman Peninsula, is another region with well-developed series of LPS. Among the earliestcomprehensive studies were works headed by A.A. Velichko in the early ۱۹۷۰s (Velichko et al., ۱۹۷۳b).Four paleosols were identified near Cape Pekla, and first paleomagnetic measurements andmacromorphological descriptions performed. Our studies focused on a plot ۳ km west of Kuchugurysettlement on Cape Pekla (۴۵° ۲۵'۵۶.۱" N, ۳۶° ۵۵'۱۲.۰" E). The section is located on a high marine terrace(Fig. ۱) forming a residual hill ۳۳۷ m high confined between two gullies, near the side of a circulardepression with stepped slopes. Several gullies have formed in the depression slope. The coastal scarp wascleaned of the outer dry and fissured layer ۰.۵ to ۱.۵ m thick. The macromorphology of the exposedsequence was described in detail, and samples taken for a complex of analyses at every ۶ cm. Here weconsider the results concerning the sediment lithology and age, namely grain size data, loss on ignition(LOI), magnetic susceptibility (MS), and optically stimulated luminescence (OSL). The data lead us toconclude that that the formation of continental series exposed in the Pekla section started at the beginningof the Middle Pleistocene. There are five well pronounced buried soil complexes (PS ۱-۵) exposed in thesequence, covering sedimentation from the Middle Pleistocene to the present day. We attribute two lowerpaleosols (PS ۴ and PS ۵) to two main warm intervals of the Middle Pleistocene – MIS ۹ and MIS ۱۳, andthe Kamenka interglacial palaeosol, correlated with MIS ۷ from other parts of the Azov loess area, isrepresented in the Pekla section by a sand layer formed at the time of the marine transgression dated tointerval ۲۲۰-۲۸۰ ka (MIS ۷). The upper soil horizons (PS۱, PS۲ and PS۳) developed between ۲۰ and ۲۲۰ ka.The Pekla section contains a considerable proportion of sand fraction – presumably, due to active eolianprocesses that developed in immediate vicinities of sources of the material. The paleosol characteristics andthe structure of loess horizons in the Pekla subaerial series differ considerably from the well describedloess-paleosol series of the Northern Azov Sea coasts. In all probability, this region of the Taman Peninsulabelongs to a specific province located south of the North Azov loess-soil province (Timireva et al, ۲۰۲۱).The loess-soil series of the Taman Peninsula appear to have considerable promise for tracing climate andenvironment changes through the Pleistocene. Future work should be centred on the dating of deposits,particularly those of the upper part of the sequence (paleosols PS۱, PS۲ and PS۳); OSL and AMS datingstudies of small mammals represents a promising possibility for the creation of a reliablechronostratigraphic chart of the Taman loess region. Research was supported by Russian Foundation forBasic Research (project ۱۸-۵۵-۹۱۰۱۰).

Keywords:

Taman loess region , Loess , Paleosol , Pleistocene , OSL-dating , South East European plain