Evidence for ephemeral middle Eocene to early Oligocene Greenland glacial ice and pan-Arctic sea ice

Online Access: Get full text
doi: 10.1038/s41467-018-03180-5
Author(s): Tripati, Aradhna; Darby, Dennis
Author Affiliation(s): Primary:
University of California Los Angeles, Department of Earth, Planetary, and Space Sciences, Los Angeles, CA, United States
Other:
Old Dominion University, United States
Source: Nature Communications, 9( Article 1038), 11p. Publisher: Nature Publishing Group, London, United Kingdom. ISSN: 2041-1723
Note: In English. 70 refs.
Summary: Earth's modern climate is defined by the presence of ice at both poles, but that ice is now disappearing. Therefore understanding the origin and causes of polar ice stability is more critical than ever. Here we provide novel geochemical data that constrain past dynamics of glacial ice on Greenland and Arctic sea ice. Based on accurate source determinations of individual ice-rafted Fe-oxide grains, we find evidence for episodic glaciation of distinct source regions on Greenland as far-ranging as ∼68°N and ∼80°N synchronous with ice-rafting from circum-Arctic sources, beginning in the middle Eocene. Glacial intervals broadly coincide with reduced CO2, with a potential threshold for glacial ice stability near ∼500 p.p.m.v. The middle Eocene represents the Cenozoic onset of a dynamic cryosphere, with ice in both hemispheres during transient glacials and substantial regional climate heterogeneity. A more stable cryosphere developed at the Eocene-Oligocene transition, and is now threatened by anthropogenic emissions.
Year of Publication: 2018
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Antarctica; Arctic Ocean; Arctic region; Benthic taxa; C-13/C-12; Carbon; Cenozoic; Climate change; Climate effects; Deep-water environment; Eocene; Foraminifera; Geochemistry; Glacial geology; Greenland; Greenland ice sheet; Human activity; Ice; Ice cover; Ice sheets; Iron oxides; Isotope ratios; Isotopes; Leg 151; Lower Oligocene; Microfossils; Middle Eocene; Modern analogs; Norwegian Sea; O-18/O-16; ODP Site 913; Ocean Drilling Program; Oligocene; Oxides; Oxygen; Paleo-oceanography; Paleoclimatology; Paleoecology; Paleogene; Paleogeography; Polar regions; Sea ice; Sea water; Southern Ocean; Stable isotopes; Subantarctic regions; Subarctic regions; Tertiary
Coordinates: N752921 N752921 W0065648 W0065648
Record ID: 2019048003
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute.