LITMIR.BIZ

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the array of sedimentary rocks, the most promising ones include mudstones, representing offshore seafloors, and sandstones, representing nearshore ones. Thanks to uplift, the only way to find fossils in the Atacama involves rolling across washes and mesas by foot or truck, finding these rocks, and keeping an eye out for a glint of bone. Whale bones tend to be relatively big, after all.

      Since Darwin’s time, many thousands of bits of bone and teeth have been collected from the Caldera Basin, some ending up in natural history museums such as the one in Santiago, founded by Darwin’s correspondents. Fossil collections from Caldera consist almost entirely of fragments of skulls, limb bones, and teeth—never complete skeletons. But the little they show suggests that the Humboldt Current of the past was different: familiar species such as whales, sharks, and sea turtles lived alongside bizarre extinct ones, including nightmarish bony-toothed seabirds, long-snouted aquatic sloths, and school bus–size predatory sharks. When I started to contemplate working in the Atacama, the problem was that we didn’t have precise ages on all of these fossils in hand—we needed one complete chronicle of rocks in the Caldera Basin. Minimally we needed to identify the correct succession of layers these fossils came from, identifying oldest to youngest; at best, we hoped to pin down the ages of each fossil-bearing layer with numerical geologic dates. Once that context was arranged, we would be able to chart the rise and fall of each species over millions of years, against the backdrop of broader changes to ocean temperature, sea level, and circulation. Wear a geologist’s hat, find whale bones, and figure out the story of how the Humboldt Current’s ecosystem came to be.

      After years of planning, correspondence, and false starts, I found myself sweating in the glare of the Atacama sun. I paused from scanning a geologic map of the Caldera Basin, spread across the hood of the Toyota pickup, and squinted, hoping to catch a glimpse of people summiting the flat top of a mesa in the distance. The harshness of the white light pinched my vision, split between the patchwork of colors on the map before me and the pale-blue dome above my head. I was frustrated, my mind elsewhere. We were late. The students on the field team hadn’t reconvened at the agreed-to time and we needed to keep moving.

      We had followed the whale bone trail in the Atacama, and the trail led us straight into fault lines—many of them. Finding fossils wasn’t exactly our problem. Instead, it was their context. We were having a difficult time piecing together the succession of rock layers in which we were finding them. As tectonic processes uplifted ancient seafloors, they also broke them up, like a layer cake dropped on the floor. Consequently, deciphering the specific old-to-young sequence of layer upon layer of rock was complicated by long, vertical fractures that displaced the layers up and down relative to one another. We tend to think of geologic faults as stretching across hundreds of miles, and that’s certainly true for some of them. But they also manifest locally, in a rock outcrop that may be no broader than the side of a house. In the Caldera Basin, faulting sometimes created a jumbled layer of rock rather than a neat stack.

      With boots on the ground, building a single chronology of rocks meant finding specific places where we could measure the thickness of the rock layer in a repeatable way, using a simple geologic tool called a Jacob’s staff. We would also note the composition, color, and texture of each rock layer. Occasionally we would also hammer out a sample of the most promising rocks—usually the ashes—in the hope of finding tiny volcanic grains that would yield precise geologic dates back in a laboratory. Through this slow, exacting work of measuring, describing, and sampling, we hoped to pin down actual dates in geologic time for enough layers in the sequence to understand the succession of different extinct species, whales and otherwise, that once lived in the Humboldt Current.

      Back at the truck, however, I wasn’t thinking about geologic maps or envisioning layers of fossil whales captured through time. Instead, I was thinking about hours wasted, miles away from the air-conditioned convenience and sprawling desk work within my museum’s walls. I thought about all of the effort and time—coordinating airfares and truck rentals, pushing permits along, accounting for family and professional commitments. As the students crested the mesa, I waved at them. What I really wanted to do was slam on the truck’s horn until it was out of air.

      Carolina Gutstein, my friend and colleague, then finishing her doctoral degree, stood with me at the truck. “You know, you can’t just rush people,” she leveled, without hesitation, sizing up my agitation like a sibling. “Trying to make things go faster here is only going to make them go a lot slower.” I laughed ever so slightly but stopped when I turned to look at her. Caro’s face was dispassionately still, her mountaineering sunglasses reflecting a stereo double of my own weary glance. I looked down in frustration, back toward the map on the hood, and exhaled. When I glanced her way again, she smiled, breaking the tension. “Why don’t we go see all those whales at Cerro Ballena?” she offered. “I’ll call Tuareg to show us around. He and Jim are over there now. You’re not going to believe it.”

      Actually, I thought that I had good reason not to believe it, especially if it involved the man who calls himself Tuareg. His real name is Mario Suárez, and he is probably the single best fossil finder I have ever known. He demurs when asked, but Mario’s self-appointed nickname is clearly meant to evoke the stoic Berber people of the Sahara—an image he routinely betrays by losing his cell phone (he has lost more than a dozen) and completely going AWOL when needed (usually found at the nearest bakery). But at the time, we were strictly in his domain, working under his collecting permit, which he held as curator at the local paleontology museum in the town of Caldera.

      Tuareg had e-mailed me earlier that year about a place he started to call Cerro Ballena, where he said complete whale skeletons had been found, but I’d had a hard time discerning much from afar. I remembered having seen the site on a past visit, a sloping road cut of the Pan-American Highway that trenched through a layer cake of orange and tan marine rocks. The only fossils I had noted were a smattering of skull bones from a large whale, likely a baleen one. Locals had tried tunneling out the bones, unsuccessfully, next to graffiti carved in the soft sandstone. None too auspicious. Fossil whale skulls are sometimes a jumble of broken bones that hardly make sense at the rock outcrop and require care and study back at a laboratory. Also, they almost always involve heavy logistics that simply outstripped our time, our resources, and, to be frank, my motivation.

      Caro’s suggestion reminded me of that whale skull we had seen together by the side of the road, although I was only burdened by the recollection to a point. If we had more time, maybe we could collect it, but we had to make hard decisions on the use of our time. We were in the Atacama to understand the evolution of the Humboldt Current ecosystem, as read from layers of fossils from dozens of species across time—doing so offered the chance to find out much more than a single broken-up baleen whale skull could ever tell us. Constructing a single stratigraphic column from the stacks of rocks across miles of fractured desert terrain was something reasonable and feasible to achieve during a single field season, if not particularly sexy. I was also on the hook to deliver publications out of our work, as a foundation for future collaborations. As it turned out, I had no clue how wrong I was about the importance of that broken-up skull at the side of the road, nor a hint about the scope of what it represented.

      If I was ambivalent about seeing Tuareg, at least I was buoyed by the thought of reuniting with Jim Parham. Jim is a like-minded scientist, a friend, and a terrific sounding board. His finely tuned bullshit detector always checked my field decisions about logistics. Earlier that day, we had split the field team in two to maximize our time: Caro and I took the students to the south, while Jim and Tuareg went north to Cerro Ballena. “I really don’t think we both should be in the same truck as Tuareg,” I said to Jim at breakfast. “Oh—just as a matter of sanity,” he assented.

      When Jim, Caro, and I had visited Cerro Ballena with Tuareg several years earlier, we’d referred to its location as “that road cut next to Playa del Pulpos,” taken from the nearest highway sign. By late 2010, it had become Cerro Ballena—literally “whale hill” in Spanish—if only because of global geopolitics, in this dusty Скачать книгу