Centres Científics i Tecnològics UB



The analysis of neodymium isotopes in marine sediment cores challenges the origin of the Antarctic Circumpolar Current (ACC)

The metal analysis laboratory of the CCiTUB has collaborated with researchers from the Faculty of Earth Sciences at the University of Barcelona and other institutions, such as Imperial College London, the Observatoire Midi-Pyrenees, the IATC-CSIC, and other universities, in a study published in the journal Nature Geoscience that questions the classical view on the origin of the Antarctic Circumpolar Current (ACC), which plays a critical role in regulating the planet's climate

This study has been primarily based on the high-precision analysis of neodymium isotopic ratios in marine sediment samples from cores in the southwestern Pacific Ocean and the southern Indian Ocean covering the last 31 million years. The study of neodymium isotopes in marine sediments allows the reconstruction of past oceanic circulation changes and requires high-precision techniques such as multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS).

A significant portion of these analyses has been conducted at UB, thanks to the dual infrastructure of LIRA-Panthalassa. The LIRA laboratory at the Faculty of Earth Sciences is a metal-free laboratory with ISO 5 certified air quality, which allows for the purification of neodymium and other elements at ultra-trace levels. Subsequently, the samples are analyzed using the Panthalassa MC-ICPMS spectrometer at CCiTUB. With these two infrastructures, it has been possible to carry out this analysis on samples containing a few nanograms of neodymium with precisions around 10 ppm, which are required to detect changes in oceanic circulation.

In this way, it has been demonstrated that, contrary to what was previously thought, the ACC did not acquire its current characteristics around 30 million years ago but more recently around 10 million years ago, questioning the theory of how the Antarctic ice sheet formed.

This study, which also involved collaboration with the CCiTUB-Geo3Bcn paleomagnetism laboratory, opens up new perspectives on understanding the interaction between the ACC and the Antarctic ice sheet. Furthering our understanding of this system is crucial for better understanding past oceanic dynamics and the potential effects of current climate change.

Link to the paper: [+]

More information about the equipment: [+]