Sunday, November 10, 2013

There it is, take it.

Out in Los Angeles they've been celebrating the centenary of the opening of the Los Angeles Aqueduct, the audacious engineering project that drained the Owens Valley and transformed the San Fernando Valley from a landscape of orchards into a landscape of tract homes and gas stations.

It just so happens that this week I've also been plowing through the final chapters of John McPhee's Annals of the Former World, his consolidated narrative of a lifetime's worth of writing on North American geology. So far, my favorite part of that book has been the section on Wyoming, in which McPhee tails USGS geologist John Love on field excursions across the state. The chapters weave the sixty-million-year history of the Rocky Mountains with the hundred-year timescale of Love's family, from his mother's arrival, via stagecoach, in a gunslinging Old West of the early twentieth century to Love's atomic age discovery of uranium in the Rocky Mountain foothills.
"Love said that a part of his job was to find anything from oil to agates, and then, in effect, say 'Fly at it, folks,' to the people of the United States."
The geologic history of Wyoming spans relatively little time in the grand scheme of Earth's history. In the last sixty million years or so, roughly one percent of Earth's lifetime, the Rocky Mountains rose up, then sank under accumulations of sand and volcanic debris tens of thousands of feet deep, then, relatively recently, rose up again and shook off the sand in freshets of new mountain streams.

And then a new geological force arrives. Ranchers arrive in Wyoming, and their sons help open up its landscapes to strip mines and oil wells. The state digs beneath the ranchers'  thin Holocene topsoil to get at the more lucrative geology of the Mesozoic era. Open-pit uranium mines, oil and gas wells, and mountain-eating coal draglines rearrange the Rocky Mountain landscape and usher in the new Anthropocene era.

Photo: Jim Bridger coal mine, from the Casper Star-Tribune.

"Fly at it, folks." Love was talking about the bounty of Wyoming's mineral resources, but it's exactly the same sentiment expressed by William Mulholland, chief of the Los Angeles Bureau of Water Works, when he opened the sluice gates of the new Aqueduct a hundred years ago and famously said, "there it is. Take it."

In the same momentous twentieth century of human history that rearranged Wyoming, Mulholland's power broker friends find cheap oil under Venice and the Baldwin Hills, and then they give the growing city a reason to burn it by moving the Owens River over mountains and irrigating the massive suburbs of the San Fernando Valley. Gravel erosion from the Santa Monica Mountains, which had washed out into the Pacific for millennia and built the vast coastal plain of the Los Angeles basin, suddenly gets trapped behind foothill dams and begins to bury the mountain canyons. The basin itself acquires new sedimentary layers of asphalt and concrete. The sooty remnants of Carboniferous swamps fly into the troposphere through millions of exhaust pipes.

Geologic time and human history converge here, in the spectacular landscapes of the American west. But remember: geologic history is full of cataclysms.