The Shape of Our Forests - A Geology Walk


A glimpse into the fascinating past of Washington Forests

Written by Erica Simek Sloniker, Conservation Information Manager
Photographed by Tomas Corsini, Northwest Photographer

Big data is all buzz in the news today, but what exactly is it?

Big data is a broad term used for data sets so large or complex that is difficult to process using traditional techniques. Geologic time is a lot like big data. The Earth’s history starts 4.5 billion years ago, but what does that really mean to our lives today? With a history so vast, how can we begin to comprehend our place in time?

I gave a geology talk to Nature Conservancy staff at a staff field trip on our newly acquired forest preserve in Central Washington, near Cle Elum. Surrounded by the Cascade mountains, the Stuart Range within the Alpine Lakes Wilderness, and on the western edge of the Columbia Pleateau, I attempted to help staff better understand Washington’s geologic history within the vast context of geologic time.

“I need 6 volunteers”, I told the group. Six people walked forward to help hold a 4.5 meter (about 15 feet) string that, when stretched out, marked a few of earth’s major geologic milestones. Each meter on the string represented 1 billion years, each millimeter 1 million years.

Washington is known for its beautiful mountain peaks, meandering coastlines, and its arid landscapes. Due to geologic forces, the Washington we know today gives us a glimpse into its fascinating and complex geologic past. The oldest rocks in Washington are dated to be around 1 billion years old. Just west of present day Spokane and Pullman, the ancient coastline of North America once boasted an abundance of life. Volcanic island arcs from far off places, collided and welded themselves to our ancient coastline, slowly adding more land mass to our state.

It wasn’t until 55 million years ago, that the Pacific Northwest had begun to approximate its present geographic configuration. Since this time, volcanic events dominated northwest geologic history including the building of the Cascade mountain range and fissuring that caused the Columbia River lava flows. More recently, 2 million years ago, a large ice sheet covered the northern portion of our state carving out deep basins like the Puget Sound and depositing vast amounts of sediment. In eastern Washington, just 15,000 years ago, enormous floods from melting ice, holding the water capacity similar of Lake Erie and Ontario, repeatedly thundered across the landscape from the Columbia Plateau to the Pacific Ocean.

“Everyone, take a look at the present day on the geologic time string”, I said. A billion years, Washington’s early beginnings, is less than 1/5th of this string. The early beginning of human kind is only a thumbnail long. Our species, homo sapians, around for just 200,000 years, is but a tiny fraction of a millimeter, unrecognizable to us on this long string.

Our lives in the present day are just a spec in geologic time, yet our actions are vital to the future condition of the ancient landscape around us and all of us who depend on it. A million years goes by fast. What will our legacy be?

G. Tomas Corsini Sr. is a freelance Northwest based photographer working on projects in Digital Media to include: Photography, Video Productions, Video Editing, Web Content Management, Motion Graphics, Graphics Illustration, and more. Learn more about his work here.