Library Notes
Rebecca Hyde – July 30, 2010


Geologists study features ranging from microscopic crystals to satellite views, from glimpses of Earth’s origins to present Earth-building events. How can these different perspectives of time and scale be combined and viewed in a larger context? Take to the air. As author Michael Collier writes in “Over the Mountains”: “On the ground, like mites on an elephant, you don’t know if you’re sitting on the elephant’s tooth or its toenail. But a view from the sky adds another dimension. Rise above and you can see the earth from trunk to tail.”

Information and entertainment, extraordinary images with text that instructs the “unschooled” --- Michael Collier’s “aerial views of geology” are picture books for adults. For people curious about geological processes (mountain-building, erosive rivers), or people who like to travel, these photographs offer access to areas accessible only to birds and pilots.

Collier is a geologist, science writer, photographer, and pilot. And using his Cessna 180 “like a tripod,” he brings into focus and records geologic features that illuminate the theories by which scientists understand our earth. He also wants to impart “a sense of wonder, a tangible sense of the earth that springs from an intimate knowledge of the land.”

In “Over the Mountains,” the map of the United States is overlaid with boundaries marking geologic “provinces,” each having its own particular geologic history. A photograph of the North Cascades (Columbia Plateau Province) shows a remarkably jumbled range of mountains. These mountains are still being created by the spreading ocean floor meeting the edge of the continent, with accumulations of silt and sand being scraped off like “peanut butter smeared from a knife onto a piece of bread.”

Again, In “Over the Rivers,” a map helps us re-imagine the landscape. State lines are overlaid by rivers, their basins, and divides, which draw the line between water flowing toward one or another river (the great Continental Divide, for example). A river’s “job description” calls for moving water and sediment from the mountains to the sea. And that means maintaining a “fastidious equilibrium” between water and sediment.

A spectacular alluvial fan is pictured within Alaska’s Glacier Bay National Park, where coarse sand and gravel is dumped when the stream runs high and hard. In contrast, as the gradient flattens, a river meanders, like a “string of wobbly railroad cars rolling down an uneven track.” Its current bears against one bank and deflects against the other, creating bends, all the way to the sea. The Green River is a “writhing snake” as it moves toward Bronx, Wyoming, leaving bright sand on the inside of bends and erosion on the outside.

Collier’s books offer us a view of a dynamic earth, a work in progress.