Southern Hemisphere initiation of the mid-Pleistocene transition.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41779841.
- Also identified by DOI 10.1126/sciadv.aea6811 and PMC identifier 12959411.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
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.