Accurate estimates of paleolatitude are critical to large-scale tectonic problems involving plate reconstructions and paleovelocities, and, thus, mantle dynamics. Traditionally, paleomagnetism is used to address these problems, but there still exist classic debates where paleomagnetic studies produce varied results leading to significantly different tectonic interpretations. Paleoclimatic and biogeographic zonation are the only other techniques that can provide direct quantitative estimates of paleolatitude. They rely on the first-order correlation between latitude and land-surface temperature. Using the relationship between the physiognomy of fossil angiosperm leaves and climate, Dr. Miller developed a quantitative paleobotanical method for estimating paleolatitude. This method has been successfully applied to problems of terrane transport in the Western Cordillera of North America—the mid-Cretaceous Baja BC hypothesis and the paleolatitude of the Early Cenozoic Yakutat block in Alaska. He has shown, in both cases, that flora-derived estimates of paleolatitude corroborate paleomagnetic results supporting low paleolatitude origins for these terranes.
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