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We present astronomically tuned high resolution (∼3–4 Kyr) 15.8-Myr long benthic foraminiferal δ 18 O and δ 13 C records from IODP Site U1337 in the east equatorial Pacific, which provide a reference standard for stratigraphic correlation of deep sea sediments. A long-term glaciation history over the past 15.8 Myr has been recorded in the δ 18 O. Two of the most significant glaciation events include the East Antarctic Ice Sheet expansion (EAIE) at 13.8 Ma and the final onset of the Northern Hemisphere Glaciation (NHG) in 3.3–2.5 Ma. A series of Miocene and Pliocene glaciation events exist between the EAIE and NHG, which are important glaciation attempts before the Earth finally entered the full “icehouse” world in the late Pleistocene. A long-term ocean carbon isotope decrease over the past 15.8 Myr has been recorded in the δ 13 C. Ocean circulation change was the major cause of the ocean carbon isotope decrease in 9.4–8.1 Ma and 4–0 Ma, whereas strengthened continental chemical weathering controlled the long-term ocean carbon isotope decrease in most of the time of the past 15.8 Myr. The divergence in benthic foraminiferal δ 13 C and ε Nd provides strong evidence of significant ocean circulation change between 12.1 and 9.2 Ma which was probably related to the formation of the Isthmus of Panama. The internal feedbacks such as continental weathering and sea surface temperature change have great potential for modulating the weak 100 and 400 Kyr signals in astronomical forcing into strong 100 and 400 Kyr signals in global ice volume and carbon cycle. [ABSTRACT FROM AUTHOR]

East Antarctic ice sheet expansion (EAIE) at ∼13.9 Ma in the middle Miocene represents a major climatic event during the long-term Cenozoic cooling, but ocean circulation and carbon cycle changes during this event remain unclear. Here, we present new fish teeth isotope ( ε Nd) and benthic foraminiferal B/Ca records from the South China Sea (SCS), newly integrated meridional Pacific benthic foraminiferal δ 18 O and δ 13 C records and simulated results from a biogeochemical box model to explore the responses of deep Pacific Ocean circulation and carbon cycle across EAIE. The ε Nd and meridional benthic δ 13 C records reveal a more isolated Pacific Deep Water (PDW) and a sluggish Pacific meridional overturning circulation during the post-EAIE with respect to the pre-EAIE owing to weakened southern-sourced deep water formation. The deep-water [CO 2 − 3 ] and calcium carbonate mass accumulation rate in the SCS display markedly similar increases followed by recoveries to the pre-EAIE level during EAIE, which were probably caused by a shelf–basin shift of CaCO 3 deposition and strengthened weathering due to a sea level fall within EAIE. The model results show that the ∼1‰ positive δ 13 C excursion during EAIE could be attributed to increased weathering of high- δ 13 C shelf carbonates and a terrestrial carbon reservoir expansion. The drawdown of atmospheric CO 2 over the middle Miocene were probably caused by combined effects of increased shelf carbonate weathering, expanded land biosphere carbon storage and a sluggish deep Pacific meridional overturning circulation. [ABSTRACT FROM AUTHOR]