Linking True Polar Wander, the Origin of the Hawaiian-Emperor Bend, the Paleolatitude of Ellesmere Island, and Cenozoic Climate Change
Abstract
Does the Emperor seamount chain record northward motion of the Pacific plate relative to the deep mantle? Did Ellesmere Island lie in the High Arctic, without sunlight for several months a year, while lush rainforest flora and fauna thrived (Eberle & Greenwood, 2012)?
We claim that these questions are linked, and that neither can be understood properly without recognizing that the Earth reoriented relative to its spin axis during the Early to Middle Eocene by a process known as true polar wander. This hypothesis follows from investigations of the apparent polar wander of the Pacific Plate during the Cenozoic and Late Cretaceous (e.g. Acton & Gordon, 1991; Petronotis et al., 1994; Horner-Johnson & Gordon, 2010; Koivisto et al., 2011; Zheng et al., 2018; Woodworth & Gordon, 2018; Seidman et al., 2019). In contrast to some currently popular views, we show that the Hawaiian hotspot was approximately fixed in latitude during the formation of the Emperor Chain, but at a latitude different from today. The hotspot was also approximately fixed in latitude during the formation of the Hawaiian Chain, but at a latitude different from both its present latitude and its latitude during Emperor time. These intervals of constant latitude are termed true polar stillstands, in which the Earth remained stationary relative to its spin axis, and that between them, around the time of the formation of the Hawaiian-Emperor Bend, the entire solid Earth reoriented relative to the spin axis by 10°±3°. This caused Ellesmere Island to move from its location near the Arctic Circle to the High Arctic, not far from its present latitude. Greenland and western Europe were also shifted to higher latitudes, while Antarctica became better centered within the Antarctic Circle. Our latest work shows that the shift did not begin until after chron 24r (54-57 Ma), which includes the Paleocene-Eocene Thermal Maximum and precedes the Early Eocene Climatic Optimum. The shift appears to have been largely completed by chron 21n (46-47 Ma). The timing suggests, but by no means proves, that the shift may have been a factor in initiating the transition from greenhouse to icehouse Earth.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.U21B..02W
- Keywords:
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- 0810 Post-secondary education;
- EDUCATION;
- 0815 Informal education;
- EDUCATION