The Real Landscapes of the Great Flood Myths

I came to Tibet in the spring of 2002 to investigate a geologic mystery: How had the mighty Tsangpo River cut through the rising Himalaya to carve the deepest gorge in the world? Origin questions like this one fascinate me. I’m a geomorphologist—I study landforms and construct scientific narratives to explain the evolutionary processes that created and molded them. For years, I believed that my stories stood apart from myth in that they were forged in the topography of real landscapes—in the shape of hills to the lay of valleys. But that was before I visited the Tsangpo.

From the airport in Lhasa, my colleagues and I drove southeast, up and over an icy pass that descended into a tributary. As we wound our way toward the main river, I was surprised to see a series of flat surfaces perched, like a giant’s banquet tables, above the bottom of the valley. Known as terraces, these enormous piles of loose sediment commonly form when a river slices into its bed, leaving older, higher floodplains behind. But many of the terraces I now beheld were capped in alternating layers of silt and clay. Such fine, orderly strata would never settle out in a turbulent mountain river like the one beside us. What were these quiet-water deposits doing in an alpine valley at the top