Arctic vegetation, temperature, and hydrology during Early Eocene transient global warming events
Willard, D.A.; Donders, T.H.; Reichgelt; Greenwood, D.R.; Sangiorgi, F.; Peterse, F.; Nierop, K.G.J.; Frieling, J.; Schouten, S.; Sluijs, A. (2019). Arctic vegetation, temperature, and hydrology during Early Eocene transient global warming events. Global Planet. Change 178: 139-152. https://dx.doi.org/10.1016/j.gloplacha.2019.04.012
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In: Global and Planetary Change. Elsevier: Amsterdam; New York; Oxford; Tokyo. ISSN 0921-8181; e-ISSN 1872-6364, more
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| Author keywords |
Palynology; Palynofacies; brGDGTs; Bioclimatic reconstructions; Paleocene-Eocene; Thermal Maximum; ETM2; Arctic; Paleoclimate |
| Authors | | Top |
- Willard, D.A.
- Donders, T.H.
- Reichgelt, T.
- Greenwood, D.R.
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- Sangiorgi, F.
- Peterse, F.
- Nierop, K.G.J.
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- Frieling, J.
- Schouten, S., more
- Sluijs, A.
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| Abstract |
Early Eocene global climate was warmer than much of the Cenozoic and was punctuated by a series of transient warming events or ‘hyperthermals’ associated with carbon isotope excursions when temperature increased by 4–8 °C. The Paleocene-Eocene Thermal Maximum (PETM, ~55 Ma) and Eocene Thermal Maximum 2 (ETM2, 53.5 Ma) hyperthermals were of short duration (<200 kyr) and dramatically restructured terrestrial vegetation and mammalian faunas at mid-latitudes. Data on the character and magnitude of change in terrestrial vegetation and climate during and after the PETM and ETM2 at high northern latitudes, however, are limited to a small number of stratigraphically restricted records. The Arctic Coring Expedition (ACEX) marine sediment core from the Lomonosov Ridge in the Arctic Basin provides a stratigraphically expanded early Eocene record of Arctic terrestrial vegetation and climates. Using pollen/spore assemblages, palynofacies data, bioclimatic analyses (Nearest Living Relative, or NLR), and lipid biomarker paleothermometry, we present evidence for expansion of mesothermal (Mean Annual Temperatures 13–20 °C) forests to the Arctic during the PETM and ETM2. Our data indicate that PETM mean annual temperatures were ~2° to 3.5 °C warmer than those of the Late Paleocene. Mean winter temperatures in the PETM reached ≥5 °C (~2 °C warmer than the late Paleocene), based on pollen-based bioclimatic reconstructions and the presence of palm and Bombacoideae pollen. Increased runoff of water and nutrients to the ocean during both hyperthermals resulted in greater salinity stratification and hypoxia/anoxia, based on marked increases in concentration of massive Amorphous Organic Matter (AOM) and dominance of low-salinity dinocysts. During the PETM recovery, taxodioid Cupressaceae-dominated swamp forests were important elements of the landscape, representing intermediate climate conditions between the early Eocene hyperthermals and background conditions of the late Paleocene. |
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