2026-06-25 デラウェア大学（UD）
＜関連情報＞
- https://www.udel.edu/udaily/2026/june/glaciers-climate-ocean-circulation-seafloor-research/
- https://www.science.org/doi/10.1126/sciadv.aea6811
南半球における中期更新世移行の開始 Southern Hemisphere initiation of the mid-Pleistocene transition
Chandranath Basak, A. K. Isuri U. Kapuge, Jesse R. Farmer, Emily Symes, […] , and Anna P. S. Cruz
Science Advances Published:4 Mar 2026
DOI:https://doi.org/10.1126/sciadv.aea6811
Abstract
The mid-Pleistocene transition [MPT; between ~1.25 and 0.7 million years ago (Ma)] marks when Earth’s glacial pacing switched from 41,000- to 100,000-year cyclicity. Here, we present a South Pacific hydrogenous neodymium isotope record tracking changes in deep ocean circulation spanning 1.5 to 0.5 Ma. This record indicates that the MPT was not triggered by Northern Hemisphere (NH) processes. Instead, the growth of Antarctic ice sheets to a critical size (~1.8 Ma) primed the climate system for the MPT, with iceberg release and melting transferring buoyancy out of the Southern Ocean. This iceberg-associated buoyancy redistribution ultimately reduced deep water formation in the NH, an observation supported by our data. Once the MPT was initiated in the Southern Hemisphere, its subsequent climatic changes were dominated by NH processes.
