Paleobotanical proxies for early Eocene climates and ecosystems in northern North America from middle to high latitudes
| Autor: | Christopher K. West, Janelle M. Vachon, David R. Greenwood, James F. Basinger, Tammo Reichgelt, Alexander J. Lowe |
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| Rok vydání: | 2020 |
| Předmět: |
lcsh:GE1-350
Global and Planetary Change 010504 meteorology & atmospheric sciences lcsh:Environmental protection Stratigraphy Biome Holocene climatic optimum Paleontology 15. Life on land 010502 geochemistry & geophysics 01 natural sciences lcsh:Environmental pollution Arctic 13. Climate action Upland and lowland lcsh:TD172-193.5 Forest ecology Temperate climate lcsh:TD169-171.8 Climate model Physical geography Water cycle lcsh:Environmental sciences Geology 0105 earth and related environmental sciences |
| Zdroj: | Climate of the Past, Vol 16, Pp 1387-1410 (2020) |
| ISSN: | 1814-9332 |
| DOI: | 10.5194/cp-16-1387-2020 |
| Popis: | Early Eocene climates were globally warm, with ice-free conditions at both poles. Early Eocene polar landmasses supported extensive forest ecosystems of a primarily temperate biota but also with abundant thermophilic elements, such as crocodilians, and mesothermic taxodioid conifers and angiosperms. The globally warm early Eocene was punctuated by geologically brief hyperthermals such as the Paleocene–Eocene Thermal Maximum (PETM), culminating in the Early Eocene Climatic Optimum (EECO), during which the range of thermophilic plants such as palms extended into the Arctic. Climate models have struggled to reproduce early Eocene Arctic warm winters and high precipitation, with models invoking a variety of mechanisms, from atmospheric CO2 levels that are unsupported by proxy evidence to the role of an enhanced hydrological cycle, to reproduce winters that experienced no direct solar energy input yet remained wet and above freezing. Here, we provide new estimates of climate and compile existing paleobotanical proxy data for upland and lowland midlatitude sites in British Columbia, Canada, and northern Washington, USA, and from high-latitude lowland sites in Alaska and the Canadian Arctic to compare climatic regimes between the middle and high latitudes of the early Eocene – spanning the PETM to the EECO – in the northern half of North America. In addition, these data are used to reevaluate the latitudinal temperature gradient in North America during the early Eocene and to provide refined biome interpretations of these ancient forests based on climate and physiognomic data. |
| Databáze: | OpenAIRE |
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