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- Title
A tipping point in stable isotope composition of Antarctic meteoric waters during Cenozoic glaciation.
- Authors
Dallai, Luigi; Sharp, Zachary D.
- Abstract
Triple oxygen isotopes of Cenozoic intrusive rocks emplaced along the Ross Sea coastline in Antarctica, reveal that meteoric-hydrothermal waters imprinted their stable isotope composition on mineral phases, leaving a clear record of oxygen and hydrogen isotope variations during the establishment of the polar cap. Calculated O- and H-isotope compositions of meteoric waters vary from −9 ± 2‰ and −92 ± 5‰ at 40 ± 0.6 Ma, to −30 and −234 ± 5‰ at 34 ± 1.9 Ma, and intersect the modern Global Meteoric Water Line. These isotopic variations likely depict the combined variations in temperature, humidity, and moisture source regions, resulting from rearrangement of oceanic currents and atmospheric cooling during the onset of continental ice cap. Here, we report a paleo-climatic proxy based on triple oxygen geochemistry of crystalline rocks that reveals changes in the hydrological cycle. We discuss the magnitude of temperature changes at high latitudes during the Eocene-Oligocene climatic transition. Variations in the oxygen and hydrogen isotope composition of meteoric waters are reconstructed using hydrothermally altered granitoids. These variations show major rearrangements in the Antarctic hydrological cycle during Cenozoic glaciation.
- Subjects
ANTARCTICA; STABLE isotopes; HYDROLOGIC cycle; CENOZOIC Era; OXYGEN isotopes; HYDROGEN isotopes
- Publication
Nature Communications, 2024, Vol 15, Issue 1, p1
- ISSN
2041-1723
- Publication type
Article
- DOI
10.1038/s41467-024-48811-2