We investigate the response of calcareous nannoplankton to the middle-late Eocene transition in the SW Neo-Tethys and compare our data to published results from X-ray diffraction (XRD) analysis, element content from X-ray fluorescence (XRF) and the abundance of microfossils in the coarse fractions of the sediment. The nannofossil assemblage is mainly composed of Reticulofenestra spp. (avg. 44%), Sphenolithus spp. (avg. 20%), Discoaster spp. (avg. 18%) and Pontosphaera spp. (avg. 10%). The Relative abundance of Zygrhablithus bijugatus and the Chiasmolithus ratio are used with the visual assessment to evaluate the preservation. The Sphenolithus-Reticulofenestra turnover occurred before the MECO at the Lutetian-Bartonian boundary. Besides the significant influence of an evolutionary gradient caused by the disappearance of numerous species of Sphenoliths, Discoasterids, and Coccolithaceae, and the first appearance of multiple species of reticulofenestrids, paleoenvironmental conditions imposed a significant impact on the calcareous nannofossil assemblages. The abundance of ostracods and the planktic/benthic foraminifera ratio depict relative sea-level changes. The microfossil assemblages and the lithological composition of the sediments track paleoclimatic and paleoenvironmental changes across the Lutetian to Priabonian. Dry conditions marked the middle Lutetian, followed by increased variability in hydrolyzing conditions during the late Lutetian and early Bartonian. An eutrophic and restricted ecosystem with high fine-grained material input is suggested for the Priabonian.

我们研究了西南新特提斯洋钙质微浮游生物对始新世中晚期转变的响应，并将我们的数据与已发表的 X 射线衍射 (XRD) 分析结果、X 射线荧光 (XRF) 元素含量和丰度进行比较沉积物粗粒部分中的微化石。超微化石组合主要由网状网孔化石组成。（平均 44%），Sphenolithus spp。（平均 20%），Discoaster r spp。（平均 18%）和Pontosphaera spp。（平均 10%）。通过目视评估Zygrhablithus bijugatus的相对丰度和Chiasmolithus比率来评估保存情况。Sphenithus - Reticulofenestra转换发生在 MECO 之前的卢特阶-巴顿边界。除了由于许多Spheniths、Discoasterids 和Coccolithaceae 物种的消失以及多种网状网孔雀属物种的首次出现所造成的进化梯度的显着影响之外，古环境条件对钙质超微化石组合也产生了显着影响。介形类的丰度和浮游/底栖有孔虫的比例描述了相对海平面的变化。沉积物的微化石组合和岩性成分追踪了从卢特阶到普里亚波阶的古气候和古环境变化。卢特阶中期为干燥条件，随后卢特阶晚期和巴通阶早期水解条件的变异性增加。建议为普里亚波尼阶提供富营养化且受限制的生态系统，并提供高细粒物质输入。