Earliest Oligocene Climate Transition and the Dynamics of Continental Ice Sheet Evolution: Constraints from High Resolution (10 4 Yr) Deep-Sea Foraminifera

PI将研究南大西洋的两个始新世/渐新世序列(DSDP柱状物522)和南印度洋的一个柱状物(DSDP柱状物748)的浮游和底栖有孔虫中稳定的碳和氧同位素含量的变化，以确定南极早渐新世冰盖是否表现出与新近纪相同的消长。如果是，信号在幅度/频率上是相同的还是不同的；即，最早的渐新世记录是否显示了米兰科维奇的胸腔？这项研究得益于古近纪地层学，特别是化学地层学和磁学地层学的改进。

The PI's will study the variation of stable carbon and oxygen isotope contents in planktonic and benthic foraminifera from two Eocene/Oligocene sequences (DSDP core 522) in the South Atlantic and one core (DSDP core 748) in the southern Indian Ocean to determine if early Oligocene ice-sheets on Antarctica displayed the same waxing and waning as seen during the Neogene. If so, was the signal the same or different in amplitude/frequency; i.e. does tyhe earliest Oligocene record display Milankovitch rhthyms? This study is facilitated by the improvement in Paleogene stratigraphy, particularly chemo-and- magneto-stratigraphies.