GSA Annual Meeting in Phoenix, Arizona, USA - 2019

Paper No. 59-4
Presentation Time: 2:20 PM


GORDON, Richard G.1, WOODWORTH, Daniel T.1, GAASTRA, Kevin1 and SEIDMAN, Lily E.2, (1)Earth, Environmental, and Planetary Sciences, Rice University, MS 126 6100 Main St., Houston, TX 77005, (2)Earth Science--MS 126, Rice Univ, PO Box 1892, Houston, TX 77251-1892

Does the Emperor seamount chain record the northward motion of the Pacific plate relative to the deep mantle? Did Ellesmere Island lie in the High Arctic, with no sunlight for several months a year, while a lush rain-forest flora and warm-weather fauna thrived? We claim that these two questions are linked and that neither can be understood properly without recognizing that the Earth moved substantially and rapidly relative to its spin axis in early to middle Eocene time by a process known as true polar wander. These results and hypotheses follow from our investigations of the apparent polar wander of the Pacific plate over Cenozoic and Late Cretaceous time. In contrast to 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 today and its latitude during Emperor time. Around the time of the formation of the Hawaiian-Emperor Bend, we propose that the entire solid Earth moved relative to the spin axis by about 900 ± 200 km. This caused Ellesmere Island to move from near the edge of 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. The shift did not begin until after chron 24r (54-57 Ma), which includes the Paleocene Thermal Maximum and part of the Early Eocene Climate Optimum. The shift appears to have been completed by ~50 Ma. The timing suggests, but by no means proves, that the shift may have been a factor in initiating the transition from greenhouse to ice house Earth.