Range chart of calcareous nannofossils from ODP Hole 188-1165B (Table 1)

Bio- and magnetostratigraphic age data and nannofossil assemblage analysis from ODP Site 1165 evidence an anomalous warming event of the surface waters in and around Prydz Bay during the Early Pleistocene, approximately 1 Ma. This results from an increase in the abundance of nannofossils at Site 1165, that occurred at 1 Ma. Detailed high-resolution sampling permits a new bio-magnetostratigraphic interpretation for ODP Site 1165. A decrease in delta18O values at Sites 1165 and 1167 also occurs at this time, supporting the presence of warming conditions in the Prydz Bay area. A return to colder surface waters, indicated by the absence or rare occurrence of nannofossils in the upper cores from Site 1165, suggests that more stable glacial conditions existed in the Prydz Bay basin, for the last 900 ka.
The biogenic carbonate sequence identified at Site 1167 is similar to the carbonate shales recovered from the Cape Roberts Project 1. Both have been dated at about 1 Ma, supporting the idea that a significant surface waters warming occurred during the Pleistocene. These data and the presence of calcareous nannofossils from locations around the Antarctic continent also suggest that the warming event was not limited to the analysed basin, but it extended around the East Antarctic continent. These new evidence call for a re-evaluation of the notion that the East Antarctic Ice-Sheet has experienced stable conditions similar to today since the late Neogene.

来自大洋钻探计划（Ocean Drilling Program, ODP）1165站位的生物地层与磁地层年代数据，以及超微化石（nannofossil）组合分析结果显示，早更新世时期（约1 Ma），普里兹湾及其周边海域的表层海水出现异常升温事件。该升温事件以1 Ma时1165站位超微化石丰度显著升高为直接表征。通过高分辨率详细采样工作，我们得以对ODP 1165站位提出全新的生物-磁地层解译方案。与此同时，1165与1167站位的δ¹⁸O值均出现同步下降，这一结果进一步佐证了普里兹湾区域存在升温环境。而1165站位上部岩芯中超微化石缺失或罕见的特征，则指示表层海水重新转为冷态，表明过去900 ka以来普里兹湾盆地始终处于相对稳定的冰期环境。
1167站位识别出的生物碳酸盐序列，与罗伯茨角计划（Cape Roberts Project, CRP）1号作业所获取的碳酸盐页岩具有高度相似性，二者的形成年代均约为1 Ma，这一发现支持了"更新世期间表层海水曾发生显著升温"的学术观点。结合本次研究获取的数据，以及南极大陆周边海域产出的钙质超微化石（calcareous nannofossils）证据，进一步表明此次升温事件并非局限于本次研究的盆地范围，而是波及了整个东南极大陆周边海域。上述全新证据亟需我们重新审视"新近纪晚期以来东南极冰盖一直处于与现代类似的稳定状态"这一传统认知。