Abstract—

The results of palynological study of the mid-upper Eocene sediments of the Aktumsuk key-section (Ustyurt Plateau, Uzbekistan), calibrated with nannoplankton data, are presented. Dinocyst stratigraphical distribution permitted to recognize five Dinoflagellate Zones from the Peri-Tethys zonation: Costacysta bucina, Enneadocysta pectiniformis, Rhombodinium draco, Rhombodinium perforatum, and Thalassiphora reticulata. First-order calibration with nannoplankton zones permitted to precise the lowermost occurrences of the key dinocyst species. Based on the dinocyst and nannoplankton data, two important stratigraphic hiatuses, corresponding to the upper Ypresian and upper Bartonian-lower Priabonian, were recognized. Analysis of quantitative fluctuations of different groups of palynomorphs through the section indicates paleoenvironmental changes in this part of the Peri-Tethys during the Lutetian-Priabonian: the beginning of significant transgressive phase in the early Lutetian, relative deepening in the mid Lutetian; after the break in sedimentation at the end of Bartianian-beginning of Priabonian the sedimentation continues again in the open-marine (outer neritic) environement.

中文翻译：

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阿克图姆苏克剖面（乌兹别克斯坦乌斯秋尔特高原）的中晚期始新世恐龙囊：生物地层学和古环境

摘要—

提出了用纳米浮游生物数据校准的Aktumsuk关键剖面（乌兹别克斯坦乌斯秋特高原）中新世上中部沉积物的花粉学研究结果。恐龙囊的地层分布可以识别来自Peri-Tethys地带的五个恐龙鞭毛区：肋藻（Costacysta bucina），果蝇（Enneadocysta pectiniformis），菱角龙（Rhoombodinium draco），穿孔菱角（Rhoombodinium perforatum）和网状拟南藻。纳米浮游生物区的一阶标定允许精确定位关键藻类物种的最低发生率。基于恐龙囊和纳米浮游生物的数据，识别出了两个重要的地层裂隙，分别对应于上伊普尔圈和上巴托尼阶-下普里亚邦阶。通过该剖面对不同类型的古脊椎动物形态的定量波动分析表明，在Lutetian-Priabonian时期，这部分Peri-Tethys的古环境发生了变化：在Lutetian早期进入显着海侵阶段，在Lutetian中部相对加深。在Priabonian的Bartianian开头的沉积中断之后，沉积在海底（外部灰岩）环境中再次继续。