WIND TECTONICS

An Yin taught an approach. First, geometry. Map what you see. Then kinematics. Then dynamics. Pursue your ideas, even if others think they are ridiculous. Follow your curiosity. Think big. This approach has led me down many unanticipated paths, and I highlight the most stimulating here. Dare I combine wind with tectonics. Wind has blown kilometers of rock from the crests of actively growing anticlines in the western Qaidam Basin during the past three million years. Qaidam anticlines are preferentially propagating in the windward direction and notably accelerated in growth concomitant with wind erosion. These observations raise the possibility that spatially variable removal of mass by wind influenced the rates and kinematics of rock deformation. To the east of the Qaidam Basin is the Chinese Loess Plateau—the largest terrestrial accumulation of Neogene – Quaternary dust on Earth. Wind processes not only built the Loess Plateau but also moved its windward margin downwind at plate tectonic rates during the past few million years. An observation that requires this is the nature of the windward margin of the Loess Plateau. It is composed of a windward-facing erosional escarpment that locally rises to ~400 m in relief like a Great Wall of Dust with fortifications of the Great Wall built along it. The process at the million-year timescale is analogous to using an atmospheric leaf blower to generate an expanding region of bedrock erosion (Mu Us Desert to the north and west of the Loess Plateau), a windward-retreating escarpment made of dust (the Great Wall of Dust), and a growing pile of wind-transported dust downwind (Loess Plateau). The escarpment is retreating in the windward direction faster than Loess Plateau rivers are incising headward. The Loess Plateau exists because here the wind is mightier than the rivers. With An Yin’s inspiration, let us continue to explore and map the Earth, from the core to the clouds, and beyond into space, and go where curiosity leads us.