دورية
Decadal warming events extended into central North America during the last glacial period
| العنوان: | Decadal warming events extended into central North America during the last glacial period |
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| المؤلفون: | Batchelor, C. J., Marcott, S. A., Orland, I. J., He, F., Edwards, R. L. |
| المصدر: | Nature Geoscience; March 2023, Vol. 16 Issue: 3 p257-261, 5p |
| مستخلص: | The connection between abrupt high-latitude warming during the last glacial period—Dansgaard–Oeschger (DO) events—and rapid climate changes at lower latitudes has revealed inter-hemispheric teleconnections in the ocean–atmosphere system. Links between DO events and climate variability in mid-latitude, mid-continent settings remain, however, poorly understood, especially in North America where climate archives with sufficient time resolution are scarce. Here we examine a speleothem that grew from ~70–50 thousand years ago (ka) in Wisconsin (United States) and combine fluorescent imaging of its growth banding with an annual-resolution oxygen isotope (δ18O) record. Eight large (2.0–3.0‰) negative δ18O excursions, each with an onset in <10 annual growth bands, occur between 61–55 ka, when DO events 17–14 are recorded in the ice core of the North Greenland Ice Core Project. Although the age model does not allow these δ18O excursions to be matched to specific DO events, their magnitude and rapid onset support a credible link. Isotope-enabled climate simulations suggest that abrupt DO warming would increase the δ18O of annual precipitation in the study area and corroborate that warming of >10 °C in <10 years is thus required to produce the observed negative δ18O excursions. Our findings of expansive abrupt DO warming in central North America has implications for environmental, climate and ice sheet dynamics. |
| قاعدة البيانات: | Supplemental Index |
| تدمد: | 17520894 17520908 |
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| DOI: | 10.1038/s41561-023-01132-3 |