Abstract In addressing the controversial issues of the Late Pleistocene paleogeography of the Caspian basin, an important role is given to the results of the spore-pollen analysis and based on them reconstructions of climate and vegetation changes in the Northern Caspian region during the development of the Early Khvalynian transgression. In this paper we present the main results of the palynological study of deposits (chocolate clays and the overlying and underlying layers from the Srednyaya Akhtuba section) of maximum stage of the Early Khvalynian transgression; the materials are illustrated by pollen diagram with the data of spore-pollen analysis and the detailed list of palynoflora recovered from the studied Lower Khvalynian sequences, and complemented with photographs of pollen belonging to the principal autochtonous taxa and, for comparison, to some redeposited palynomorphs. Palynological materials indicate subaqual (brackish marine and freshwater) sedimentation of the sediments studied in periglacial landscapes and, for the most part, under very harsh climatic conditions. The performed climate-stratigraphic reconstructions do not contradict the data of absolute dating on the accumulation of the studied deposits during the Late Valdai (Ostashkov) late Glacial period. During this interval in the territory of the study area, plant communities of the glacial climate — tundra-steppe, periglacial forest-steppe, periglacial steppe, periglacial parklands and periglacial forests — were developed. The widespread occurrence in the composition of the periglacial vegetation cover of the studied region of the yernik formations from Betula nana and shrub communities from Betula fruticosa, B. nana, Alnaster fruticosus, Juniperus, etc. testifies to the severe climatic conditions and, possibly, the existence of sporadic permafrost in the cold stages (stadials) of the Ostashkov Late Glacial period.

中文翻译：

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里海演化的早期 Khvalynian 阶段：花粉记录、孢粉植物群和古环境重建

摘要 在解决里海盆地晚更新世古地理有争议的问题时，孢粉分析结果具有重要作用，并以此为基础重建里海盆地发展过程中北里海地区的气候和植被变化。早期 Khvalynian 海侵。在本文中，我们介绍了早期 Khvalynian 海侵最大阶段的沉积物（巧克力粘土和 Srednyaya Akhtuba 剖面的上覆和下伏层）的孢粉学研究的主要结果；材料用花粉图说明，包括孢粉分析数据和从研究的下赫瓦利尼阶序列中回收的孢粉菌群的详细清单，并辅以属于主要本土分类群的花粉照片，作为比较，到一些重新沉积的孢粉体。孢粉学材料表明，在冰缘景观中研究的沉积物的水下（咸水海洋和淡水）沉积，并且大多数情况下，在非常恶劣的气候条件下。进行的气候地层重建与晚瓦尔代 (Ostashkov) 晚冰期期间所研究沉积物积累的绝对年代测定数据并不矛盾。在研究区的这一区间内，发展了冰川气候的植物群落——苔原草原、冰缘森林草原、冰缘草原、冰缘公园和冰缘森林。来自桦木的 yernik 地层和来自 Betula fruticosa, B. nana 的灌木群落的研究区域的冰缘植被覆盖的组成中广泛存在，