No Stone Unturned

Peter Haff Devotes 25 Years to Studying Nature's Desert Pavement p.3

  Suspecting that animals were involved in this “dance,” he set up an experiment that placed large desert beetles in an aquarium together with color-coded pebbles of different sizes. To this menagerie of biology and mineralogy he sprinkled in daily doses of fresh desert sand.

  He found that the beetles moved the smaller pebbles more frequently and over longer distances than the bigger ones. The smaller pebbles were also more frequently tipped sideways, and in a way that allowed the sand to sift underneath them. The results over time were that smaller pebbles got uplifted above the sand. Meanwhile, larger pebbles tended to get buried. He labeled this beetle instigated process “biolevitation.”

  The results of this biolevitation mimicked what Haff and other scientists had observed in the field—that the stones seemed to be able to keep on top of the accumulating layer of dust. The sideways random motion also seemed to explain how pavements could heal themselves. For example, desert pavements tend to self-repair damage from 18th century wagon tracks with nearby fresh stones that are smaller (and thus more easily moved) than the pavement stones outside those tracks.

  Meanwhile, Haff left Caltech to become a postdoctoral fellow at the Niels Bohr Institute in Copenhagen, “nominally doing nuclear physics but actually doing planetary science that was kind of geological,” he recalls. Then he moved to Yale for more research in nuclear physics. “But every chance I had I went out west,” he says. “I was a senior research associate at Caltech for many years with no responsibilities,” he adds. “But after a while you get a family and a mortgage and your costs go up. So I thought, ‘I’ve got to get a real job.’”

  That was when a job opened up at Duke’s department of civil engineering. While Haff jumped at the opportunity, he soon persuaded academic leaders to let him switch to geology, completing a career shift that had begun years before. “What that means is you have some strange gaps in your knowledge,” he jokes. “Like: ‘Does Triassic come before or after Jurassic?’”

  Now a professor of geology as well as division chair, Haff’s continuing forays into the desert have become somewhat legendary.

  Tales that he once attracted the attention of a concerned backcountry deputy after crawling under a vehicle to escape the heat are only half-truths, he insists. What really occasionally happened was that a sheriff’s office would notify his wife, Suzanne, that his car had been spotted unoccupied in the desert. “I’d just go off and leave it for a few days,” he recalls, noting that he made sure his wife knew where he and the car were supposed to be.

  Nicholas School Dean William Schlesinger, himself a veteran of Mojave research, recalls sharing a lunch of canned beans warmed (as if heat was necessary) on the engine block of Haff’s four-wheel-drive Ford Bronco. Haff said before buying his SUV he actually managed to drive into the badlands in an old two-wheel-drive Dodge Dart. Looking back, he’s not sure how he did it.

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